# Question
Title: Why do people try to make themselves feel better by treating others poorly?
I'm looking for an explanation for why people will try to make themselves feel better by treating others poorly.

For example, imagine a group of girls are sitting in a cafe. Within that group are two girls in particular, Sally and Anne. Sally is beautiful, intelligent, and popular. Sally knows she's blessed, but she doesn't like to highlight that fact. She shies from attention and deflects most compliments. Anne on the other hand, is normal, at least she thinks of herself as normal. Anne doesn't often receive compliments like Sally does. As the group of girls sit in the cafe sipping latte's and chatting, the conversation makes its way to Sally's recent success at school. Sally scored top of the class in the last bout of exams. This angers Anne, she herself didn't do so well on her exams. She feels ashamed. Suddenly she blurts "Oh Sally its great that you did well on your exams, I'm surprised you had so much time to study, I thought you'd be too busy with Jack?". Jack was Sally's fiance, they recently split up when Sally caught Jack with another woman. At this, Sally cowers like a wounded animal. She quickly mumbles something and excuses herself from the table. The conversation falls flat. Everyone at the table knew what happened between Sally and Jack. The other girls stare awkwardly at their mugs, shooting furtive looks at Anne. Anne knows what she did was wrong, evil even. But hurting Sally felt good, real good.

To rephrase the question in the context of the scene: Is there a name for Anne's behaviour at the cafe?

I'm not just looking for a word that would describe Anne's behaviour. Depending on how you interpret the story, Anne's behaviour can be described with many words (bullying, jealousy, spitefulness etc.). What I'm looking for is an explanation of Anne's behaviour in terms of psychoanalytic theory.

# Answer
```
What I'm looking for is an explanation of Anne's behaviour in terms of
psychoanalytic theory.

```

In Freudian psychology this is called Displacement:

> ... an unconscious defense mechanism whereby the mind substitutes either a new aim or a new object for goals felt in their original form to be dangerous or unacceptable.

For example:

> ... a college student may snap at his or her roommate when upset about an exam grade.

Note that psychoanalytic theory is outdated, and for the most part considered pseudoscience. The concept of defence mechanisms in general has largely been superseded by cognitive dissonance theory.

Not related, but you may also be interested in Schadenfreude.
> 5 votes

# Answer
**When a person feels inferior to another,** then the only way they can replace that feeling of inferiority is to find a way to control that person's emotions from displacing their own. Their visible dominant emotion becomes jealously - in extreme cases this can manifest itself as anger and violence.

**Some people particularly men** can becomes jealous of a woman's beauty and see rape as a punishment rather than a pleasure. This in their mind justifies the rape. They see the rape as a release from the torment they have had to endure by not feeling equal to the attractiveness in the exchange of emotions with others

**Any method of dealing with rapists** will only succeed if the feeling of low emotional worth is dealt with.

**They are jealous of the lack of control** of the situation they are in, and that the other person is able to use that control to direct interaction and actions.

**Example of free-exchange.** I make a joke that Obama'a revenge on America for not awarding him President of all Time Award is Donald Trump. You laugh. We have entered into free exchange of emotion. Nothing is asked of each other other than free-exchange. I gave you my opinion in the form of a joke and you rewarded me with your laughter.

After the exchange we both feel equal to each other and have the 'feel good' emotion.

**We can then carry on our interaction on equal terms.**

Those who wish to hurt need to use their emotions in the form of power in order to that. The visible display of the success of that change of emotional superiority is for that person to see the hurt they have casued with their power.

Trolls are a good example.Some are highly organised groups of people who take pleasure in exerting emotional control over others with verbal abuse.

The simplest way to combat this is to make sure you publicly display them and their comments and of course use the law to prosecute them.

**Your question is a topical one.** As from it I have explained how interaction is formed by the free exchange of emotion and how that free exchange can becomes in teh ownership of one person by hurting the other.

**Of course in a face to face conversation you can identify the speaker - it is a question to ask should the Internet do the same?**
> 2 votes

# Answer
It can be devaluation principle in narcisstic personality disorder.

http://en.wikipedia.org/wiki/Narcissistic\_personality\_disorder
> 0 votes

# Answer
Spitefulness: having or showing a desire to harm, anger, or defeat someone.
> 0 votes

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Tags: social-psychology
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# Question
Title: If the color black reflects no light, how are we able to see it?
If color as we perceive it is dependent on the wave lengths that are reflected by an object, with white reflecting all hues and black absorbing all, how do we detect a black object?

I do understand there is no such thing as a perfect black. Is it this physical imperfection of black surfaces that provides the visual system with a cue about its shading?

# Answer
> 7 votes
Objects are visually perceived when they reflect light. A black object does not reflect any light. In other words, no photons are reflected to be detected by the photoreceptors in the retina. A black shape on a colored background appears black because its brightness approaches zero relative to its surroundings.

Black, as any other perceived hue, is a relative perception. The visual system, as any other sensory system, detects physical stimuli in a relative way. For example, under bright daylight (photopic conditions) a camera flash might appear as a weak source of light. That same flash viewed under dark (scoptopic) conditions may appear as a blinding flash. When the visual system is **light-adapted**, it needs a lot of photons to be able to respond to a visual stimulus. Under this condition, dark colored objects may **appear black**, simply because the photoreceptor's thresholds are too high. Conversely, that same dark object may appear as gray under scotopic conditions when the retina is **dark-adapted** (colors are not perceived under scotopic conditions - note here that **black and white are *not colors***, but the two extremes on the perceived gray-scale).

An important thing to realize is that colors are perceptions and subject to neurophysiological processing imperfections. For example, blind people **rarely perceive the world as black**, despite the fact that their visual system cannot detect photons. Instead, they may perceive the world as a grayish hue, they often experience illusionary spontaneous flashes of light (phosphenes), or even entire visual scenes (Charles Bonnet syndrome). Hence, while a *black object* is physically defined as *an object that emits/reflects no photons*, it does not mean that the corresponding area in the neural representation of the visual field is silent. Perhaps on the contrary.

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Tags: perception, vision, sensation, neurophysiology
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# Question
Title: Environmental cleanliness: what is cognitively fresh?
The concept of freshness has developed over the last century to involve a range of sensations and responses to tastes, smells and feelings associated with foods, the environment and cleaning products. But what is it that contributes or tells us that something is fresh from a neurocognitive perspective? It seems unlikely that freshness be merely the absence of negative stimuli that promote a disgust response, as freshness is often associated as a positive response.

I know this is a wide ranging question, however there is surprisingly little research on a concept that advertisers use daily, to promote cleaning products. Its unusual that such a important perception and its associated behaviour has so little academic research. Funny how merely watching the adverts between TV shows can make you curious!

**EDIT:**

The exact questions are...

1. What are the cognitive factors that make humans or animals perceive something to be fresh/clean?
2. What are the neurocognitve mechanisms underlying these processes?

# Answer
> 1 votes
Freshness is a term which is widely used to identify odors. The olfactive stimuli which is trigerred by fragrant materials like citruses, aromatics( lavender, rosemary), peppermints or green materials (like leafs or grass) these are more volatile groups they are light molecules and usually refer to freshness. But the cool or fresh sensation not just come from the olfactive perception or identification it is because of the trigeminal nerve fibers which are responsible of sensing temperature and irritating substances. It is both temperature and the identification why there is a common freshness perception.

EDIT: All the cleansing products which are perfumed, tested durig the wet and dry stages to examine power and hedonic scales. So perfumes inside the product need to be percieved during wet and dry stages and fragrant materials need to diffuse quickly to create a first impression: here something is about to be all clean. These kind of diffusion only obtained with the volatilest chemicals which are mostly triggered trigeminal nerves and creating a fresh or cool sensation.

Doty RL. Intranasal trigeminal detection of chemical vapors by humans.

Interactions between Olfaction and the Trigeminal System: What Can Be Learned from Olfactory Loss

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Tags: motivation, cognition
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# Question
Title: Why do people have different personalities when speaking different languages?
Edit: This study is much more relevant in terms of the question.

This study suggests (according to article linked below) that a multilingual person can have multiple personalities, each tied to one of the languages that he or she speaks.

Here's an article about the study.

One personality may be active when the person is interacting in one language, another when interacting in another language, etc.

I have seen this phenomena very distinctly in myself.

Why does this happen?

# Answer
> 6 votes
That is a really interesting question. There are some studies that found that the emotional response is strong in one's native language compared to languages that are acquired later. For instance, a study by Harris and colleagues found that physiological arousal was stronger to swear words or childhood reprimands in the first language of the participants compared to a fluent second language \[1\]. For bilinguals, the response was similar for both languages.

Coming back to your question, this could indicate that people might display different personalities, because they judge the emotional content of language differently in their non-native language. This could have to do with the context in which the language was learned, i.e. in infancy versus classroom learning. Alternatively, differences in exposure might make a difference, because hearing words and phrases in many different context provides a better understanding of their connotations.

\[1\] Harris, C. L., Aycicegi, A., & Gleason, J. B. (2003). Taboo words and reprimands elicit greater autonomic reactivity in a first language than in a second language. Applied Psycholinguistics, 24(04), 561–579. http://doi.org/10.1017/S0142716403000286

# Answer
> 9 votes
This is a typical example of the misrepresentation of scientific reseach in popular media.

The orignal study concludes that "language effects on cognition are context-bound and transient, revealing unprecedented levels of malleability in human cognition". The word "personality" does not appear in the original paper. Nevertheless the Daily Mail comes to the conclusion that "\[s\]peaking two languages really could give you a split personality, researchers have found". No, they haven't.

To understand what is going on here, I recommend the following video to you:

https://www.facebook.com/LastWeekTonight/videos/896755337120143/

So what *does* the study find? It finds that the different grammatical structures of different languages can influence how people perceive the world and process information. (Please note the word "can" here! It does not always happen, and only to a small extent.) This is an old hat and called the Sapir-Whorf hypothesis.

As for how this changes the "personality" of multilingual speakers: It doesn't. It changes the *information* that the speakers use to assess the situation and plan their behavior.

# Answer
> 5 votes
Both of my parents and I are multilingual. We come from Czech Republic and have learned multiple languages through our lives as we moved around.

I have noticed, even within myself that I "feel" different speaking a European language compared to English.

Not being able to go into the neurobiology of brain plasticity and change within when developing with multiple languages I can give my understanding through Psychology.

I think that language can be contextual in different parts of a persons life if it is a progression in time from one language to another as opposed to learning multiple languages at the same time. This in turn can build associations that bind the language with emotion at the time of learning the language.

For example, when I learned Czech until I was 7, which I have a different emotional connection and association with. So when I hear it and speak it I feel different. I feel calmer and my stress level decrease, I also realised I have different reactions to circumstances.

However when I deal with day to day life in English I feel more assertive and actually aggressive in my speech and reactions.

I believe that the learned associations between the language and the persons life can create a type of personality that isn't necessarily a split personality as it is the same cognitive person.

Sorry if I used the wrong expressions in trying to describe the scenarios from my own experience and introspection on the same topic.

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Tags: personality, language, psychology, cross-cultural-psychology
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# Question
Title: How do people with a split brain experience reality?
Some people with severe epileptic seizures have the connection between their two brain halves cut. How appears reality for them, and why does this procedure helps them?

# Answer
The ***corpus callosum*** is the largest of the commissural neural pathways, linking the cerebral cortex of the left and right hemisphere. The sectioning of this tract is called a *corpus callosotomy*, which disconnects the two sides of the neocortex.

A callosotomy is used in cases of intractable epilepsy, *i.e.*, epilepsy that cannot be treated sufficiently with medication.

Patients with their *corpus callosum* severed have been shown to have difficulties in tasks that require lateralized brain areas to work together. For example, the left visual field is processed in the right hemisphere in the brain (and *vice versa*), speech and language centers are primarily located in the left hemisphere (in most people) and the right hemisphere specializes in visual-spatial processing and facial recognition.

When experiments are done under laboratory conditions, the **lateralization of the brain** becomes quite evident in these patients. For instance, a compelling experiment is shown in Fig. 1. When a split-brain subject is shown a word in the right field of view, the image is processed in the left hemisphere in the brain. The case shown shows the typical case where the language centers reside in the left hemisphere too. In this case, the subject is able to say what the word was ('*face*'). However, when the same word is shown on the left, the visual image is processed in the right hemisphere, where the speech centers are less well represented, if at all. In this case ***the subject cannot verbalize what they saw, but they are able to draw it***(!). And in fact, subjects may ***say they saw nothing at all when a visual stimulus is presented on their left side, but still make a motor response to it*** (e.g., press a button when instructed to do so when a stimulus pops up).

Fig. 1. Split brain experiment. source: Nature

**Why does callosotomy help epilepsy patients**? When conventional methods fail to treat severe forms of epilepsy (intractable epilepsy), sectioning the *corpus callosum* may help to prevent the seizure from spreading from one hemisphere to the next. Generalized seizures result in loss of consciousness only when both hemispheres are affected. Often, seizures start in a hot spot, called an epileptic focus. From there it spreads over the cortex and the subject gradually loses consciousness. Once it jumps over, via the *corpus callosum*, the subject loses consciousness entirely. Hence, severing the major connection between the two hemispheres can keep seizures from evolving into full-blown generalized seizures. However, callosotomies have been really rare in the past and they are hardly performed today, due to the advances made in anti-epileptic drug development, combination therapies, micro surgery, *etc*.

**Resource**
**-** Nature News, March 2012
> 4 votes

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Tags: neuroscience, cognitive-neuroscience, neurophysiology, epilepsy
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# Question
Title: What is the purpose of non-spiking and anaxonic neurons?
What is the purpose of non-spiking neurons and anaxonic neurons in neural tissue?

# Answer
The standard textbook neuron receives input at its dendritic tree, fires action potentials and has a single, long output axon to send the message off to distant locations.

However, non-spiking, anaxonic neurons are not a rarity; in various sensory systems there are bipolar cells present that lack a clearly defined axon and are non-spiking, such as the amacrine cells and the horizontal cells in the vertebrate retina (Fig. 1.) and the granule cells in the mammalian olfactory bulb (Hisada, 1989).

Generally, non-spiking neurons work as analogue integrators. Where a spiking neuron can only transmit a spike, or no spike (binary signal), a non-spiking neuron can convey an infinitesimal number of membrane voltages instead. Hence, it is well suited to integrate the input from various other neurons. Amacrine cells and horizontal cells lack clearly defined axonic elements and are thus non-spiking anaxonic neurons. Their dendrites, however, do form synapses with other neurons, generally on their dendrites too, forming dendro-dendritic connections. The function of the bipolar cells in the vertebrate retina are unclear.

There are other non-spiking anaxonic neurons identified. A notable example are the interneurons seen in the ganglia of the motor systems of various arthropods, including crayfish, locusts and cockroaches. Here, they are coupled to neurons that convey descending output to motoneurons, and they are thought to be involved in selecting the adequate information to be gated to the motoneurons (Takahata *et al*., 1981), or to be necessary for generating oscillations in the system (Pearson & Fourtner, 1975). But again, their exact functions are unclear. One reason why may be because they are local circuit neurons. In other words, they do not send their signals far off to distant locations because they lack clear axons. For example, the role of the retinal ganglion cells becomes readily apparent when you sever their long axons that are bundled in the optic nerve (one becomes blind in that eye).

Fig. 1. Retinal circuitry showing the non-spiking, anaxonic horizontal and bipolar cells. Source: David Hubel's Eye, Brain, and Vision

**References**
**-** Hisada, *Arch Histol Cytol* (1989); **52**(Suppl): 139-46
**-** Pearson & Fourtner, *J Neurophysiol* (1975); **38**(1): 33-52
**-** Takahata *et al*., *Brain Res*; **226**: 309-14
> 2 votes

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Tags: neuroscience, neurophysiology
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# Question
Title: Is there a link between intelligence and mental disturbances?
Is there a link between high intelligence or creativity, measured with currently valid psychometrics, such as IQ tests or tests of creativity and mental disorders like depression, anxiety, or bipolarity?

# Answer
> -1 votes
I like Mr Smitherson's consideration, which is indeed in the realm of possibilities. I haven't read a definitive study yet, I will search and return soon.

However, for further consideration to the question from a psychological/cognitive perception I posit the following:

Persons with abnormal, on the high scale of intelligence, would perhaps have more varied considerations when presented with a situation or when presented with a problem.

People with a higher IQ would normally think deeper into a problem. This would activate more brain cells, and drain the brain of the chemicals it uses to function. This would lead to imbalance.

The second consideration is that people who are more intelligent, would think about things further. To expand on that idea, since I am not the best at explaining stuff, I'll give an example: a person, of high IQ, is presented with information on global warming, a normal (for the sake of argument) person would take in the information and perhaps think "this isn't good" and leave it there. The person of higher IQ would thinking further about the implications, perhaps research and may find the situation hopeless.

Constant barrage of these situations may lead to lower moods and the elevated hopeless thinking lead to depression fueled by anxiety for the future.

This is what I would consider to be the cause behind any correlation between intelligence and mental illness in the form or depression/anxiety (these two conditions feed each other into a spiral)

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Tags: intelligence, creativity
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# Question
Title: Is touch sensitivity higher for females?
I read a long time ago that in a study of two-week old infants response to touch, the female babies were far and away more sensitive. In most gender comparisons, there are the familiar "two humps" in the distribution of responses, but in this case, **the male and female response ranges did not even overlap**: the most sensitive male infant was less sensitive than the least sensitive female.

Has this sort of difference been shown in more recent research and with other age groups? It seems to me that it would have to be innate, because two weeks is not a long time to be affected by cultural differences. I would think that this difference would persist with age, and would explain a lot of the difference in how men and women function during sex, or any sort of intimate touch.

# Answer
> 2 votes
**Short answer**
Females are more sensitive to some, but not all somatosensory stimuli. Males are either less sensitive, or as sensitive as females.

**Background**
A normative study by Blankenburg *et al*. (2010) determined reference values for a battery of somatosensory tests including cold detection threshold (CDT); warm detection threshold (WDT); thermal sensory limen (TSL); cold pain threshold (CPT); hot pain threshold (HPT); pressure pain threshold (blunt pressure, PPT); mechanical pain threshold (pinprick, MPT); mechanical pain sensitivity (pinprick, MPS); wind-up ratio (WUR); mechanical detection threshold (MDT); vibration detection threshold (VDT) in male and female subjects in the age range of 6 - 16 years.

**Girls were significantly more sensitive to CDT, WDT, TSL, CPT, HPT and PPT.**

**No significant difference was found for MPT, MPS, WUR, MDT or VDT.**

However, the authors note that some of their findings did not match that of other studies. For example, better thermal detection in female than in males as found in their study matches the data in adults of previous studies, but did not match other studies that also used kids. The lack of sex-dependency of mechanical pain sensitivity contrasted other studies in children and adults.

I would suggest reading Blankenburg *et al*. (2010) for more details.

Another study showed female infants to have lower electro-tactile thresholds (are more 'sensitive') than age-matched males (Lipsitt, 1959).

<sub>**References**
**-** Blankenburg *et al*. *Pain* (2010); **149**: 76–88
**-** Lipsitt, *Child Development* (1959); **30**(4): 547-54</sub>

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Tags: neuroscience, perception, sensation, sex-differences, touch
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# Question
Title: How to think about things when it's the right time?
Is there a good way to train that?

To be able to pause thinking about something that you can't change right now, until it's actually time. That might be one day, one week or one month later.

# Answer
What you refer to is probably 'controlling' your mind, which is a common practice called 'mindfulness training', i.e., learning to observe thoughts without interacting with them.
> 3 votes

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Tags: wandering-mind
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# Question
Title: Is this expected to happen while asleep?
I always knew that, while asleep, stuff like processing words and/or reading texts could not be done by the brain. I'm not even a student in the area, so by *knew* you could understand as *vulgar knowledge*.

What I noticed many times is that in my dreams I read and pay attention to words, and the most recent case was right today, when I composed a verse making fun of an existent melody (to put in context, is when you want to mock a song in some way). While the context of the verse and dream was given to my subconscious by my recent obsession about missing playing poker with my friends, what seemed unusual to me is that I did that in a vivid way to the point I remember it letter by letter (and laugh about).

The reason I ask about this is: Is this an expected thing that happens while asleep or could be a sign of a health problem? (don't know: stress, insomnia, or even something I should worry about)

An appropriate answer should be backed by a meaningful and reputed research result.

# Answer
> 2 votes
The appropriate answer is that dreams are generally not in any way diagnostic of a health issue. Being able to read while dreaming is absolutely not diagnostic. I can't imagine that any reputable research has been done on this topic.

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Tags: sleep
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# Question
Title: Brain-computer interface with EEG: how to name imaginary movement of a non-self object?
I am working on Brain-Computer interfaces. In my project we try to control the movement of a robot in three directions, namely forward, right and left.

We have done an EEG experiment where we have asked subjects to *imagine* the movement of this robot to the wanted direction. For example, if the subject wanted to move the robot forward, he needed to imagine the robot was moving forward.

Is this type a **motor imagery** experiment? If not, what would the scientific word be that describes this type of experiment?

# Answer
As far as I know, brain-computer interfaces based on EEG use motor-cortex responses by asking the subject to imagine body movements. *E.g.*, a left-arm movement imagination would translate to moving the robot to the left *etc*. In other words, imagining the robot going left will probably result in a diffuse, poor-defined brain response, while imagined motor movements are more useful. See a slide presentation here on this topic.
> 4 votes

# Answer
I agree with Christiaan. Similar movements are stored nearby and are thus difficult to distinguish (see How are movements stored in the brain? ), even more so with the spatial resolution of EEG. What I would like to add is that for imagery to be motor imagery, you have to imagine the movement in first person perspective. Imaging someone else to execute a movement will not show in the motor cortex. This is a nice paper showing result of novices using a new BCI.

BCIs go further than steering a Robot or a pointer on the screen (which can be achieved in a similar fashion). BCIs are also used for disabled peopled who cannot speak for instance. For this they have developed a P300 speller: a matrix of letters which one by one flicker at a high speed. Whenever the letter that you were thinking of highlights in the screen, a strong P300 can be recognized in an ERP. In this paper, multiple algorithms are compared for its accuracy.

A final way of BCI makes use of the frequency spectrum (see this paper for example). By focussing more or less, relaxing more or less etc, the power in the different frequency bands will vary. At our university we have a game called mind-ball, a very simple one-vs-one game where you have relax as much as possible (have high alpha and theta) to move a little ball to your opponents side of the table.
> 3 votes

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Tags: terminology, eeg, brain-computer-interface
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# Question
Title: What is the maximum time difference to still associate an acoustic and visual event?
I am developing a game where the music needs to be synchronized to the actual game logic. That means that some objects in the game react to events in the music. Of course, the music will never be completely synced to the output on the screen, so I need an indication of the time difference so I can sync the music manually to the game logic.

What is the average/maximum time for a human to still associate a visual event on the screen with an auditory musical event?

# Answer
**Short answer**
In the case of simple stimuli, visual and auditory stimuli can be offset between **25 and 50 ms** and still be perceived as coming from one and the same same event.

**Background**
The question can be re-phrased as *what is the **window of integration** of **intersensory asynchrony** in case of visual and auditory stimuli*?

A well-known example where these two stimulus modalities are perceived as separate, while they are in fact coming from the same event, is a thunder heard *after* lightning. This is caused by the fact that sound travels at a speed much slower than light, and hence a thunder can lag lightning by seconds.

source: NASA

In many instances, however, a multimodal perception is actually perceived as being synchronous, while they are in fact offset in time due to differences in physical characteristics of the stimuli. Take the storm as an example - when it is far away, the thunder is perceptually dissociated from the lightning, because the sound lags the light by seconds. But when the thunderstorm is close enough, the auditory crack and visual lightning are perceived as synchronous, while in fact they are still offset because of the sound travelling so much slower than light.

So the question becomes, as you rightfully ask, what are the *margins* in which stimuli across modalities can be asynchronous while perceived as one event? In other words, what is the *window of integration*?

Vroomen and Keetels (2010) conclude in their review on this topic that a stimulus asynchrony in the case of auditory beeps and visual flashes can be between **25 and 50 ms** and still be perceived as coming from the same event.

The window of integration between more complex stimuli can be much greater. For example, the window for **speech and visual information** can be as large as **203 ms**. Such large windows of integration point toward higher processes playing a role in the brain. Only temporal lags **below 20 msec** are expected to go **unnoticed because of hard-wired limitations** on the resolution power of the individual senses.

Hence, Vroomen and Keetels (2010) argue there must be **higher processes** at work in the brain that actively synchronize percepts that are offset in time, but seem to belong to one and the same event. One such mechanism is referred to as *temporal ventriloquism*, which means that a *perceptual modality is **actively shifted in time** to match it with another modality*. This effect is most pronounced in visual stimuli, in that a visual percept is actively adjusted in time to match a sound or tactile stimulus. Likely visual percepts are shifted preferably by the brain, because the visual system is the slowest of all the senses.

**Reference**
Vroomen & Keetels, *Att Percept Psychophys* 2010; **72**(4): 871-84
> 3 votes

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Tags: perception, vision, hearing
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# Question
Title: Can humans keep track of two unrelated rhythms?
Let's do an experiment. With your left hand start tapping out a regular (evenly-spaced) beat - say, 2 beats per second. With your right hand attempt to tap our a different regular beat, but tap at a rate that is "as unrelated as possible" to the first beat - something like 3.14159 beats per second. (Here "as unrelated as possible" is weakly defined. Basically, I mean to keep two rhythms that are both regular but will never be in sync.)

My question is this: **Is it possible for a human to actually keep accurate track of both rhythms? Or will they interfere with one another so that the rhythm of one or both hands is lost?**

My own (admittedly unjustified) model of neuronal behavior is that rhythmic action of the left hand must correspond to rhythmic patterns of neural activity in the brain with the same frequency. And similarly, rhythmic action of the right hand must correspond to rhythmic patterns with that frequency. Since, I suspect, the task of tapping out a rhythm requires coordination across several areas of the brain, then it seems that the a-periodic neuronal firing would likely interefere and cause one rhythm or the other to become dominant - or both rhythms to be lost entirely.

(Oh... and for the sake of this question, assume the corpus callosum is intact. Missing CC is cheating here.)

# Answer
I never thought that my Bachelor Thesis would ever come in handy. Thank you for this question!

**Short answer**
No, you cannot keep up two unrelated rhythms in a stable coordinated fashion when tapping for your finger for instance.

**Long Answer**
Let us start with (and skip over) the oldest paper that I have about it. Haken, Kelso and Bunz (1985) described in a mathematical model how you would coordinate two rhythmic movements (tapping fingers) and how you change phases. In-phase means you tap at the same time, whereas anti-phase means you tap with one whilst going up with the other and vice versa. I will not describe these formula, but now you know they exist.

From now on, I will refer to "two agents" instead of fingers. I do this, because the coupling and rhythm is not limited to body parts. Even different people start to get synchronized during rhythmic movements. Richardson (2007) showed that people, without explicit instructions, started to synchronize their movements in a rocking chair. However, also during walking/running, people start to synchronize (Nessler, 2012).

What research over the years has shown that (stability of) rhythmic movements rely on three factors to be coordinated.

* First, you need to be coupled, i.e. you must be able to see/feel the other agent's rhythm. When you don't perceive a rhythm, their is nothing to adapt to (See also Richardson, 2007; Nessler, 2012; Meerhof & De Poel, 2014).
* Second, the phase of the movements: Moving in-phase is very easy and you can do that from low frequencies up to very high frequencies. Moving in anti-phase is a little more difficult. The agents will be stably coordinated at low frequencies, however, as you increase the frequency it will be more and more difficult to keep it up, ultimately leading to a synchronization period, after which you'll move in an in-phase pattern (try it out; Meerhof & De Poel, 2014).
* Third, as I already said just now: The frequency of movements. At low frequencies movements are easier to coordinate in a stable fashion than higher frequencies (Konvalinka, 2011)

In this last study, two participants in different rooms listened to a beat (of either 96, 120, 150 Hz, which could differ between participant) for eight seconds, after which they had to continue that beat by tapping their index-finger. Following, depending on the condition, they (1) kept hearing the computer-generated beat, (2) listened to their own generated beat, (3) listened to the beat of the other subject while the other heard his own generated beat, or (4) the two participants hear the beats generated by the second participant. There were many many results given all these conditions. What it all came down to was that the participants' own beat-frequency moved toward the other's, and that the rhythm became less stable, when they listened to the beat of the other participant. When the participants heard each other, the frequencies moved to each other and ultimately produced a very stable beat (they synchronized).

This paper thus showed that, whenever you are coupled (which fingers always are, it's called proprioception) you tend to synchronize. It is thus impossible to keep rhythm when you perceive a completely unrelated beat.
> 6 votes

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Tags: perception, cognitive-neuroscience, motor, synchronization, coordination
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# Question
Title: Neuronal differences of linguistic statements
Assuming that the brain (structure) is only constructed using neurons and synapses, then what is the difference between the following linguistic statements from a 'mechanical point of view'?

* Bob is a builder.
* Bob should be a builder.
* Bob must be a builder.

In each statement, there are the same "neurons" involved: "Bob" and "builder". I am trying to understand how both neurons could be connected/modelled in each statement in order to differentiate between the semantics.

# Answer
> 1 votes
Your question reduces to "what are the neural mechanisms behind language?", which is very much a work in progress.

The only neural model of language that I currently know of is the Semantic Pointer Architecture (SPA), which is largely theoretical and only has some super basic examples.

Basically, the SPA represents language as vector manipulation. The vectors are represented in neurons using the Neural Engineering Framework.

For more details on how this is done, check out "How to Build a Brain" by Chris Eliasmith and the work by Peter Blouw who is trying to solve part of this problem with his PhD thesis.

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Tags: theoretical-neuroscience, cognitive-modeling, brain-development, linguistics
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# Question
Title: What is the relationship between visual attention network and visual stream (Two-streams hypothesis)?
There are two visual attention networks proposed by Maurizio Corbetta and Gordon L. Shulman (2002). These are top-down and bottom-up attention networks.

> One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected.

There are also two ventral streams proposed by Melvyn A. Goodale and A. David Milner (1992). These are ventral stream and dorsal stream.

> We propose that the ventral stream of projections from the striate cortex to the inferotemporal cortex plays the major role in the perceptual identification of objects, while the dorsal stream projecting from the striate cortex to the posterior parietal region mediates the required sensorimotor transformations for visually guided actions directed at such objects.

My question: **What is the relationship between these two proposed networks?** As in do they affect each other, or is one a preliminary network that occurs before the other? There have been studies on this but I am having difficulty making sense of them.

Example: Visual streams and shifting attention (Brown 2009) http://www.sciencedirect.com/science/article/pii/S0079612309176045

> To gain insight into the relationship between M/dorsal and P/ventral activity and deploying visual attention, we used a covert cuing paradigm to manipulate attention while bottom-up and top-down perceptual stimulus variables created M/dorsal and P/ventral-biased conditions. One study examined the object advantage, where responses are faster for within-relative to equidistant between-object shifts of attention. Visual stream contributions to object- and spaced-based attention were revealed using psychophysically equiluminant conditions expected to reduce M/dorsal activity. Other studies investigating visual stream contributions to location-based inhibition of return (IOR) used IOR magnitude as an indicator of the ease or difficulty of deploying spatial attention. Greater IOR was found under P/ventral-biased conditions. Less IOR was found under M/dorsal-biased conditions.

# Answer
> 3 votes
My short answer would be that there is no clear relationship between these two models about how visual information processing works in the brain. However, the terminology and evidence overlaps considerably which makes this confusing.

One way to think about this is that the two models are explaining different stages of processing. The two visual streams is somewhat more general and it is very much founded on brain anatomy (lesion studies in animals and neuropsychology). It is to do with what happens to the visual information that comes into the brain, and the theory is that while some of it is processed to consciously recognise stuff (ventral), a separate pathway is involved with supplying visual information for action.

None of this is explicitly about "Attention". Corbetta and others are trying to relate brain structures to experiments in typical observers where processing changes even though stimuli are perceptually available. Although their two networks are sometimes called "dorsal and ventral", because of the involvement of superior/inferior brain regions, this does *not* imply that they map on to Milner and Goodale's visual streams. There are several other differences in anatomy.

It seems likely that *both* top-down and bottom-up attention can modulate perceptual processing in *both* visual streams (and they interact too!). It might help to think of some examples...

* If you are more likely to act on something when it is more salient (e.g., avoiding a colourful obstacle without thinking about it) then this suggests the "bottom-up" system has detected the obstacle and prioritised it's processing for action (dorsal stream).
* If you are voluntarily told to pay attention to something, and you are quicker to act on this, it suggests that "top down" attention has enhanced the dorsal stream.
* If you are voluntarily told to pay attention to something and you are quicker to recognise it, then this would be an effect on conscious
recognition, thought to be part of the ventral stream.
* If your attention is captured "bottom-up" by something, this is also going to make you better at consciously recognising it with your
ventral stream.

Here, and here are a couple of recent neuroscience papers on the attentional systems involved, and here is a classic paper showing attention is coupled in both perception and action streams.

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Tags: neuroscience, vision, neural-network, attention
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# Question
Title: Can cognitive science improve psychology?
I was wondering what your guys thoughts were about cognitive science making unique contributions to improve the methodological and theoretical foundations of psychology?

Can it make unique contributions? Will it ever be able to replace psychology? What about the replication crisis of psychology? Does this have an impact on the reputation of cognitive science?

Looking forward to hearing your thoughts.

# Answer
> 5 votes
Answering this question is very difficult without first agreeing what "cognitive science" is (a problem for this very site!). Unlike another answer here, to me, cognitive science is not necessarily about neuroscience methods (that would be cognitive **neuro**science). Instead, cognitive science is an interdisciplinary hodgepodge of people doing empirical psychology, computer science, linguistics and philosophy of mind. And I say this as a member of the Cognitive Science Society. Although neuroscience is often involved, cognitive science is much older and historically linked to computing, AI and the cognitive revolution.

It certainly has made, and will continue to make, unique contributions to psychology. One can argue about the overlap between cognitive psychology and cognitive science (to me it is considerable), but theories of information processing from computing, computational models, linguistic theory and many other examples can make more precise predictions which people can verify with empirical data (these people are normally psychologists). This improves psychology which has sometimes suffered from being too vague ("boxology").

Because I see CS as an umbrella including psychology, I don't think it makes sense to think of it "replacing" psychology.

Because CS has often included people doing empirical experiments on human behaviour, the replication crisis certainly has implications (though it may be buffered by it's emphasis on theory). Cognitive psychologists are certainly guilty sometimes, though much of the soul-searching on replications, p-hacking etc comes from experimental social psychology.

# Answer
> 2 votes
Most likely cognitive science and psychology fields will come together into one field of study, but only with technical improvements to be made. This trend has already begun, with more psychology departments conducting experiments that involve neuroimaging or EEG.

Cognitive science, while attempting to be a scientific field with empirical methods, has its theoretical backgrounds in psychology (such as attention, working-memory, consciousness, and so on). This provides a limited credibility to the current findings of cognitive science. We only know certain areas are activated during a task, but vague localization of brain area to a task is not enough for the understanding of brain mechanisms that is desired for practical applications. Only when experimental methods become higher resolution (enough to fully explain brain activities and behaviors with activations of certain neurons) will cognitive science become a full-fledged science.

On the other hand, psychology theories have been based on observations of behaviors and assumptions made by psychologists. With more concrete information from cognitive science, psychologists would be able to update their theories that are better backed by experimental evidence.

For replication crisis, well it comes from a lack of emphasis on replication studies by the research funding system in place as well as a lack of understanding of statistics (incorrect use of p-values). There is indeed a cross-effect of psychology replication crisis affecting cognitive science reputation because the term cognitive psychology is used often and interchangeably with cognitive science recently. That's not the only issue for cognitive science, though. Cognitive science has its own study "validity" crisis in that cognitive scientist may find some significant activation in some area and relate it to some other characteristic just because of some correlation. One outstanding example is the study that found significant differences in brain activation between Republicans and Democrats (really?).

**References**

Nice book about limitations of cognitive science in current state: http://www.amazon.com/Brain-Imaging-Cannot-About-Consciousness/dp/0199838720

Republican-Democrat brain study: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0052970

Republican-Democrat brain study debunked: http://www.science20.com/science\_20/republican\_and\_democratic\_brains\_debunked\_hopefully\_last\_time-119666

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Tags: psychology
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title: Why do we like expected surprises?

text:
# Question
Title: Why do we like expected surprises?
The ambiguity effect says that we try to avoid uncertain outcomes. Still, many products are selling well excactly because they give uncertain outcomes. One example is Kinder Eggs, and many similar candies\toys. Some shops also get rid og their spare products by selling them in 'surprise bags'.

**Why do people like buying products with uncertain outcomes, if the ambiguity effect is true?**

# Answer
> 2 votes
There is no ambiguity as such with respect to expectations in those examples. When you buy a Kinder Egg, you know up front you won't know what's in there. In other words, it's perfectly unambiguous that you don't know what to expect from a Kinder Egg.

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Tags: consumer-psychology
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# Question
Title: Any documented applications of engineering psychology?
Do you know about any documented application of engineering psychology?

If you know about something, please provide your answer with a reference.

# Answer
> 1 votes
After some brief research, it seems that most mechanical forms that are designed with human use in mind are examples of engineering psychology. Engineering psychologists specialize in the relationship between humans and the products we use every day.

Tufts University, MA, offers a major in engineering psychology called "Bachelor of Science in Human Factors Engineering (Engineering Psychology)" which seems to support this idea.

So any tool that has been designed specifically to improve the relationship between humans and their working environment is an applied example. Take, for example, this hilarious hamster wheel desk. Probably not the greatest example of engineering psychology, but an interesting example anyway.

Perhaps a more practical example, taken from a text-book:

> Research by engineering psychologists has demonstrated that using cell phones while driving degrades performance by increasing driver reaction time, particularly among older drivers, and can lead to higher accident risk among drivers of all ages. These and similar research findings are instigating state regulation of cell phone use.

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Tags: cognitive-psychology
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title: can mushroom improve your memory?

text:
# Question
Title: can mushroom improve your memory?
Mushrooms have several benefits. One of these is psychological. Can mushroom improve human memory?

# Answer
> -1 votes
Mushrooms contain psilocybin, which gets converted into psilocin. These act on serotonin receptors, which may play a role in memory. (Edits coming later)

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Tags: cognitive-psychology
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title: Differential equations in psychology

text:
# Question
Title: Differential equations in psychology
I am wondering (and searching with no success) if there are any examples of differential equations in psychology?

I mean, no tutorial explaining what is differenetial equations or even partial differential equations, but a research (like in emotions or social psychology, or cognitive psychology) by psychologists that use these equations to model the data?

**\[update, 29.05.2016\]** Stack Community always reminds me that the quality of the answers depends on the question asked. Just as *a good question is half of the problem*.
I'll try to make myself clear with an example. I thought about an article in psychology, say about cognitive dissonance, emotions, coping or else, that use differential equations to decribe phenomenon *without* invoking physics or chemistry or other hard science. Article by Deboeck & Bergeman introduces pendulum model(Christiaan's comment). But I don't have to refer to physics when doing ordinary squares regression, so that's why I thought it is possible to use differential equations without explicite references to physical models.

June 2, 2016: I never suggested we could "use differential equations without explicit reference to physical models". I have always said the same: the mathematical interpretation of cellular processes has lost prominence (owing to further research). The biological processes obviously remain; the interpretation has not been able to hold. Teresa Pelka

# Answer
The Hodgkin and Huxley model of neuronal firing is based on non-linear differential equations. A significant portion of research on sensation and perception is based on such models.
> 8 votes

# Answer
A large and notable area within psychology to which differential equations are central is dynamical systems theory. It is widely applied to cognitive science. Differential equations are used to describe (model) the states on one or more dimensions that a system can take which changes over time. Dynamical systems have been widely used to model cognition.

Many applications of dynamical systems theory in psychology accordingly concern questions classically within the scope of cognitive psychology, but there are examples from other areas like social and developmental psychology.

Mind that dynamical systems theory originated within physics, specifically mechanics, and that accordingly it has been widely used to model material processes. However the use of models from physics is not uncommon in psychology (think of conceiving the circadian rhythm as a harmonic oscillator (pendulum) or Lorenz' psychohydraulic model of motivation) and the states of some modelled system can be highly abstract and ›non-physical‹.

Since dynamical systems have been discussed here to some extent, I am referring you to this and this question instead of providing more information here.

Let me however second the recommendation of Schöner's »Dynamical Systems Approaches to Cognition« in Sun (ed.): Cambridge Handbook of Computational Psychology (2008) there for a decent overview, and point out a passage on nonlinear dynamical system modeling in R.W.J. Neufeld's chapter »Mathematical and Computational Modeling in Clinical Psychology« in Busemeyer et al. (eds.): The Oxford Handbook of Computational and Mathematical Psychology (2015).
> 4 votes

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Tags: methodology, computational-modeling
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# Question
Title: Effect of variability due during motor skill training
When training fine motor skills, are identically setup practice sessions ideal or, like machine learning, does adding noise/variability to the practice session increase skill acquisition?

# Answer
According to "Motor Skills Are Strengthened through Reconsolidation" (available through SciHub) adding variability to practice sessions increases learning speed. In the paper, patients were directed to move a cursor on a screen to certain targets via pinch force. Patients who's pinch force mapping was modified during each trial ended up learning faster and performing better on the original pinch task.
> 4 votes

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Tags: cognitive-psychology, learning, motor
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# Question
Title: What's the relation between firing of dopaminergic neurons and dopamine dispersion in terms of neurophysiological processes?
**Question: How does the firing of dopaminergic neurons affect the dispersal of dopamine?**

**Evidence of my limited familiarity with dopaminergic neurons and motivation for asking the question:** Most of what I know about dopamine and dopaminergic neurons comes from reading papers on reinforcement learning and its possible neuronal implementation. I was surprised to see that (if I've understood correctly) firing of dopamininergic neurons might encode an error signal like the one propagated in simple temporal-difference learning (like in Schultz et al. 1997), while dopamine itself seems not to be involved in such basic aspects of learning but instead in higher levels of hierarchical reinforcement learning, like constructing representations of the environment found in model-based RL to be used in executive functions and generalizing and applying learnt information in novel tasks. I suspect that firing of dopamininergic neurons affects the dispersion of dopamine , but I'm not sure if my suspicion is the result of a misunderstanding.

**Hypothetical context for an answer in case the question is too broad:** I'm imagining a group of dopaminergic neurons, some with axons extending to some brain region *A* and others with axons extending to brain region *B*. Say the neurons with axons extending to brain region *A* fire more than the others. This means they will produce more dopamine, and I suspect more dopamine will be present in *A*, but I'm having trouble finding supporting evidence.

# Answer
I've mostly figured it out now, and I've a better idea of the words and phrases I need to search to get the information I was asking for.

The short answer comes from wikipedia: "The neurons' somata produce the enzymes that synthesize dopamine, and they are then transmitted via the projecting axons to their synaptic destinations, where most of the dopamine is produced." The transmission is a direct result of the firing of the neuron, so DA is dispersed, in the areas where dopaminergic axons end, proportional to the firing of the neurons.

A more complete answer would involve an understanding of the difference between tonic and phasic transmission, for which this has proved an informative and accessible source.

The above sources support the suspicion I mentioned in the hypothetical context provided in the question.
> 3 votes

# Answer
Dopaminergic neurons synthesize dopamine and release it at their synapses with target neurons (see David Sulzer's review article. The activity of a dopaminergic neuron (its instantaneous firing rate) is one of the main determinants of how much dopamine is released per unit time at its many synaptic terminals. The amount of dopamine synthesized is also important.

There are many other factors that influence the extracellular concentration of dopamine in the brain, including, but not limited to, the **number and distribution of synaptic vesicles** (which sequester the dopamine until it is released into the synaptic clefts), the **number and distribution of calcium channels** (which control how much calcium enters each synaptic terminal in order to trigger fusion of synaptic vesicles with the plasma membrane), and the **amounts and types of dopamine transporters** (that traffic dopamine from the synaptic cleft back into the presynaptic terminal and then back into synaptic vesicles).
> 2 votes

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Tags: neuroscience, neurophysiology, reinforcement-learning, dopamine
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title: EPSP/IPSP amplitude values?

text:
# Question
Title: EPSP/IPSP amplitude values?
I'm working with a Hodgkin-Huxley model that receives synaptic inputs from presynaptic neurons. If it receives a spike from an excitatory presynaptic neuron, the voltage of my HH neuron inceases by an amount $g$. If it receives a spike from an inhibitory neuron, the voltage jumps down by an amount $g \times K$ (so K is the factor controlling how much the voltage drops relative to how much it would increase from an excitatory neuron). I read in textbooks that the ratio of excitatory:inhibitory neurons is generally $4:1$. That implies that for the system to be "balanced", I should have $K=4$. If $K\<4$, then there is a net drift upwards in voltage towards the threshold values, and for $K\>4$, there is a net drift downwards away from the threshold.

I have two sub-questions:

1) Is there a typical value of $g$ (the EPSP amplitude) that is biologically plausible? I've seen anywhere from $0.1-0.5$ and above which is quite a big range. I know that there is often a big range based on stimulus and whatnot, but I'm looking for a biologically reasonable value.

2) What is a typical value of $K$? In other words, what is the size of a typical IPSP amplitude relative to the EPSP amplitude? I've seen anywhere from the amplitude being the same to the amplitude being 4x the EPSP amplitude (which of course is a mighty big range).

# Answer
> 1 votes
By definition, current-based synapses are biologically implausible. After all, biological synapses are conductance-based \[1\]. It is possible that current based synapses are sufficient to answer the question you are asking. It is also possible that they are not. Generally, biological plausibility is not a matter of the parameter values you are using but rather a matter of whether the question you are asking has biological relevance. After all, unless you have a morphologically accurate simulation including every single receptor type, etc. your model is not biologically realistic.

The question you are asking doesn't have a good answer because you are asking a biologically non-sensical question: what is the value of current based synapse magnitudes?
The only way one could possibly answer that question is if one knew why that question needs an answer. Maybe you don't even need a reasonable value for the question you are trying to answer because the phenomenon is robust. Maybe you need the answer to the fifth decimal place because your model is very sensitive to that value.

Point is, biological realism is incredibly context-specific.

\[1\] Although I have heard a strange argument that the high resistance at the spine neck means that synapses are practically current sources. I don't know anyone that relies on that.

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Tags: theoretical-neuroscience, computational-modeling
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# Question
Title: What advantages does a neuron with multiple dendrites have?
What advantages does a neuron with multiple dendrites have, as opposed to one with fewer dendrites?

# Answer
More dendritic input makes a neuron more suitable as an **integrator**. The more dendrites a neuron has, however, the less faithful it will transmit a single incoming signal, as other incoming input may interfere with transmission. Hence, a neuron with a single dendrite will be better suited to faithfully **relay** incoming signals.

Among the most faithful neurons are the **cone bipolar cells** in the central part of the retina, who receive a single input and transmit a single output (Purves *et al*., 2001) via a single axon to the retinal ganglion cell who's axons make up the optic nerve, while on the other end of the spectrum there are, *e.g.*, the **Purkinje cells** in the cerebellum that can receive input from as many as 80,000 fibers (Konnerth *et. al*, 1998).

**References**
**-** Konnerth *et. al*, *PNAS* (1998); **87**: 2662-5
**-** Purves *et al*. (eds.), editors. *Neuroscience*. 2nd ed. Sunderland (MA): Sinauer Associates (2001) Functional Specialization of the Rod and Cone Systems
> 6 votes

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Tags: neurophysiology
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# Question
Title: When was cognitve dissonance discovered?
I am trying to understand when cognitive dissonance was first defined. Would mental health professionals have known about the concept of cognitive dissonance in 1972?

# Answer
Glen McGhee's "A Cultural History of Cognitive Dissonance," (2005/2014) notes that Gustav Ichheiser (1897-1969) dealt with personal dissonance and dissonance reduction in 1928 (212 Note 2). Also Kurt Lewin's tension theory, and Festinger's level of aspiration work in 1940.

Lorne L. Dawson also has an interesting chapter, "Clearing the Underbrush: Moving Beyond Festinger To A New Paradigm For The Study of Failed Prophecy" (2011) that reminds us of the seminal role that Festinger/Riecken/Schachter, "When Prophecy Fails" (1956) plays in the development of cognitive dissonance theory.

Cognitive dissonance has been a part of social psychology and experimental psychology for a long time -- but what do you mean by "mental health professionals"? How were they trained? Where did they go to school? In the 1970s, there were numerous therapies, including Gestalt, Rogerian, Reichian, Freudian, Jungian, etc. Or are you talking about social workers? MSWs?
> 3 votes

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Tags: history-of-psychology, cognitive-dissonance
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# Question
Title: Is it possible to read words a person thinking about via EEG headsets?
There are now a number of EEG headsets that can capture bran signals and give you raw EEG data from brain. EPOC Emotiv is one the famous one with I guess 14 channel. Now as the title of this post reads, my question is if it is really possible to analyze the raw data and print out what the person is trying to say without speaking? There is a difference between it's not possible and it's too hard to extract the data. From my understanding so far, the signals are different from person to person so perhaps there could be a training program so that the person can train it as to what word he or she meant and the program later can detect the meaning of that particular signal. Is this really possible? If it's hard, how hard it is?

# Answer
> 2 votes
What Christiaan says true. It is sheer impossible. However, there is technology that cán "see your mental pictures". In a TED-talk by Mary-Lou Jepsen she explains how fMRI and machine learning algorithms are used to recreate viewed or imagined videos from brain activity. It is a really neat TED-talk and definitely worth watching.

What is possible using EEG is to make a Brain Computer Interface. I discussed this topic briefly in another question (Brain-computer interface with EEG: how to name imaginary movement of a non-self object?). Hopes these answers help you somehow.

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Tags: cognitive-neuroscience, eeg
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# Question
Title: What regulates the strength of motor signals?
I've seen cognitive and robot models where the input signals from the sensors are directly used as the signal for outgoing motor control.

This doesn't make much sense, because obviously we're able to do heavy work with our muscles quite independently from the strength of incoming signals from our sensor systems. However when I consulted several books on general cognition, I wasn't able to discover the source of these arbitrarily strong signals - I'd suspect the thalamus.

I wonder how you could perform a task, *e.g.* playing a piano, by applying weak or strong force. Both the plan (how to move the fingers) and the feedback (how it sounds) signal would remain the same.

So **where does the signal for motor behavior originate, and more importantly what (or who) regulates its strength? Where does the extra energy come from?**

# Answer
**Short answer**
Muscles are controlled by motor neurons in the spinal cord. The number of motor neurons that fire, as well as their individual firing rates govern the control of muscle force.

**Background**
Muscles consist of contractile elements: the **muscle fibers**. These muscle fibers are under direct control of the **motor neurons** in the spinal cord (Purves *et al.*, 2001), as shown in Fig. 1. The motor neurons in the spinal cord are under direct control of the **motor cortex** in the brain. When the motor neurons fire, they release acetylcholine, which in turn makes the muscle fibers **contract**. The force in which a muscle contracts is basically governed by how **strong a single muscle contracts**, and **the number of muscle fibers** that are recruited.

Firstly, there is the **rate code** that allow motor neurons to regulate muscle force. An increase in the rate of action potentials fired by the motor neuron causes an increase in the amount of force that the associated motor unit (*i.e.*, one or more muscle fibers) generates. When the motor neuron fires a single action potential, the muscle may only slightly twitch. If the motor neuron fires at high rates, however, the second action potential may arrive at the muscle unit before the muscle has had time to recover from the first twitch, and that second action potential will produce a greater amount of force than the first. This is due to an increase in strength of muscle contraction through **action potential summation**. This process has a limit. When the successive action potentials no longer produce a summation of muscle contraction (because the muscle is at its maximum state of contraction), the muscle is in a state called tetanus and is pushed to its limit (source: Neuroscience Online).

Secondly, there the **recruitment** of motor neurons (size principle). When a signal is sent to the motor neurons to execute a movement, motor neurons are not all recruited at the same time, or at random. The motor neuron size principle states that, with increasing strength of input onto the motor neurons from the higher brain centers, smaller motor neurons are recruited first, while the larger motor neurons are recruited only when the motor signal increases. Why does this orderly recruitment occur? Because of Ohm’s Law, a small amount of synaptic current will be sufficient to cause the membrane potential of a small motor neuron to reach firing threshold, while the large motor neuron stays below threshold. As the amount of current increases, the membrane potential of the larger motor neuron also increases, until it also reaches firing threshold. This process is called **recruitment** and results in more motor neurons to be activated when the brain signals for the need for a high contractile force. More motor neurons will recruit more muscle fibers (source: Neuroscience Online).

Fig. 1. Motor neurons from the spinal cord innervate the muscles. source: SE Veterinary Neurology

**References**
**-** Purves *et al*. (eds), *Neuroscience*, 2nd ed. Sunderland (MA): Sinauer Associates. Motor Neuron-Muscle Relationships
**-** University of Texas, Houston Health Science Center. Neuroscience Online
> 5 votes

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Tags: neuroscience, sensation, physiology, motor, neurophysiology
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title: Does oxytocin reduce brain activity?

text:
# Question
Title: Does oxytocin reduce brain activity?
In the book "Psychologie" by Richard J. Gerrig, Philip Zimbardo I read there are studies claiming that:

> "die gegenwärtige Forschung legt nahe, dass das Hormon eine facettenreiche Rolle bei persönlichen und sozialen Prozessen spielt" (IsHak et al., 2011)

*Translation*: Recent studies suggest that the hormone plays a diverse role in personal and social processes

Another study was carried out in order to examine the effects of oxytocin on trust. In this study, half of subjects where given a dose of oxytocin, and the other half not. Furthermore, they carried out fMRT scans to examine the areas on which the oxytocin had an effect on. The study showed that:

> die Scans ergaben, dass Oxytozin-Teilnehmer weniger Aktivität in GehirnRegionen aufwiesen, die wie Amygdala mit Furchtreaktionen in Zusammenhang stehen. (Baumgartner et al., 2008)

*Translation*: The scans suggested that participants who were given a dose of oxytocin showed less brain activity in regions which are, like the amygdala, associated with fear.

Unfortunately, I do not have access to the paper where this seems to be described (Baumgartner et al. 2008).

**To what extent does oxytocin reduce brain activity and in which regions?**

Baumgartner, T., Heinrichs, M., Vonlanthen, A., Fischbacher, U., & Fehr, E. (2008, May 22). Oxytocin Shapes the Neural Circuitry of Trust and Trust Adaptation in Humans.

# Answer
**Short answer**
The dreaded *it depends*.

**Background**
This question was discussed behind the scenes in chat and we concluded with the consensus on explaining why this question is hard to answer.

Basically, you are asking on the suppressive effects of oxytocin on the brain.

First, it depends highly on the brain area under investigation. Many, and perhaps all imaging studies focus on a few promising structures in the brain. Those promising structures (**regions of interest**) need to be identified by prior research. The effect on amygdala and other fear centers has already been answered in the question (suppression). So to answer this question, one has to review all the existing literature to find any brain structure that is suppressed. This community is not here to conduct literature reviews, or write review papers. We're here to concisely answer focused questions, as outlined in the help center. As written there, the *why* and *how* questions are great. The *what*, *where* and *how much* questions like this are questionable questions.

Second, suppression is relative. If you investigate a subject in a certain state (e.g., terrified, when experiencing feelings of love or hatred) and test a drug such as the love hormone oxytocin, it may, or may not have totally different effects. The physiological state is very important. Suppressive actions can become evident in a hyperactive system, but have the opposite effect on a neural system that is relative inactive. It is all not so black-and-white. Hence - again - questions need focus and be outlined such that borders exist that emphasize, and most importantly limit the scope of the question.

In all, my answer is that it depends on the brain area under investigation and on the physiological state of that brain area.

Note. We do appreciate all your background research, your efforts in improving the question and I seriously do love neuroscience. It's my job, it's my passion, it's my hobby. Please feel more than free to further refine your interesting question and please also feel more than encouraged to continue to enrich this site with your contributions.
> 1 votes

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Tags: neuroscience, fear, oxytocin
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# Question
Title: Where can I find good references about the neuronal connections in various areas in the cortex?
As an example, I would like to know which Brodmann areas innervate the layer IV of area 10 in the brain.

To which degree are these connections known? What are good books or other kinds of resources that provide information about this, perhaps in a tabular form?

# Answer
**Diffusion tensor imaging** (DTI for short) may be the technique you are after. It is able to record nerve fibers in MRI images. I couldn't find the specifics you were after, and the subdivision into layers may outrun the resolution of MRI, but it may be a good start. Two references that may get you going on tensor imaging are cited below. Additional, targeted **electrophysiological** papers on your area of interest may provide layer-specific connections.

<sub>**References**
**-** Aggarwal *et al*., *Neuroimage* (2015); **105**: 198–207
**-** Christoph *et al*., *Cereb Cortex* (2014); **24**(2): 328–39</sub>
> 2 votes

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Tags: neuroscience, neuroimaging, neurophysiology
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title: Why does marijuana cause anxiety?

text:
# Question
Title: Why does marijuana cause anxiety?
Marijuana is getting increasingly used in medical settings. However, one of its disadvantages is anxiety. Does anyone know the reason behind the anxiety? Is it from the marijuana itself, or does it result secondarily due the effects of the marijuana, because, *e.g.* the user is not comfortable with the effects?

# Answer
Cannabis can cause an acute and short-lasting episode of anxiety, which often resembles a state of panic. When taken in high doses these effects can be intense and turn into attacks of panic and phobia. About 20–30% of users show brief acute anxiety reactions after smoking the drug. These symptoms tend to occur more in drug-naive subjects and in novel or stressful environments. In contrast, long-term users typically report that cannabis reduces their anxiety (Crippa *et al*, 2009).

Anxiety is also one of the main manifestations of the cannabis withdrawal syndrome. Its onset is typically between the second and sixth day and lasts from 4 to 14 days.

The main active psychoactive ingredient in cannabis, delta-9-tetrahydrocannabinol (THC), affects serotonergic, noradrenergic, GABAergic and glutamatergic transmission, but there is relatively little known about how it exactly induces anxiety. One of the reasons being that the psychotic effects of cannabis consumption has received way more attention, likely because it is a more severe side effect than the anxiety symptoms. Cannabidiol has been associated with an anxiolytic effect, perhaps through its effects on 5HT1A receptors (Crippa *et al*, 2009).

It has been shown that the amount of anxiety also depends on the genetic make-up of the user (Otten *et al*., 2016).

Acute intoxication could also lead to anxiety secondary to impaired cognitive functioning and the clouding of consciousness (Crippa *et al*, 2009), as mentioned in the question by the OP.

**References**
**-** Crippa *et al*., *Hum Psychopharmacol Clin Exp* (2009); **24**: 515–23
**-** Otten *et al*., *Addict Biol* (2016); \[Epub ahead of print\]
> 5 votes

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Tags: psychopharmacology, anxiety
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# Question
Title: Is it possible to quantify/measure the effect of certain medication on our neurotransmitters and hormones?
Is it possible to display the effect of taking for example Prozac on level of Serotonin and other neurotransmitters/hormones in the body?

More generally speaking s is it possible to say: taking 1mg of medication A increases hormones B and C within 3 months by 2 units for the majority of people? or perhaps not this accurate but by some accuracy?

or taking food A, increases hormones C and D?

In other words is it possible to quantify the effect of any drug/food to the body?

# Answer
Yes it is possible, but it is difficult. The way it would be done currently is to insert a needle into the base of your spinal cord to measure the concentration of a metabolite of serotonin, 5-HIAA, in the fluid surrounding your brain.

It is also possible to measure levels of this metabolite in saliva, urine, or in the bloodstream, but these measures would not necessarily represent the levels of serotonin in your central nervous system (brain). This is because serotonin plays a role in other (non-brain) bodily functions, and serotonin can not cross the blood-brain barrier. In other words, only serotonin that has been produced in the brain can be used by the brain.
> 3 votes

# Answer
Yes but antidepressants are in a class of their own! We do measure the serotonin, etc in R&D and food consumption and various other lists of increasing the drug and decreases in the body and gathered during clinical trials in the FDA and then continually monitoring is part of the process of legalization and why you see some drugs suddenly pulled from the market. But the brain is still the least understood part of the body in the medical community. The most commonly prescribed antidepressants are currently SSRIs, preventing serotonin,5-HT, from being reabsorbed, as their name, selective “serotonin reuptake inhibitors”, indicates. That resulted in all black box suicide warnings via the FDA bc we just don't know nor understand enough about them and our brain to predict their unpredictable behavior.For example Brintellix,the newest version of the SSRI and It is different enough from the welter of SSRIs currently available that it’s not simply a ‘me too’ drug. By its developer’s own admission, no one knows what effects are produced by 5 of the 6 functions Brintellix was designed to cause. But we do know that the 6th function, serotonin/5-HT reuptake inhibition, ( may cause suicidal behavior in a unique class of individuals:All of the other 5 functions interfere with normal brain activity—and the manufacturer admits that no one knows what those effects will be!Studies show Inexplicable violence, turned both inward and outward,( is the result of SSRIs causing a single change to brain function. )Brintellix causes several changes. These changes involve the handling of glutamate, which is a critical amino acid that’s required for brain function and cellular metabolism. Glutamate is necessary—at proper levels, in the right places, and at the right times—for learning, remembering, thinking, and emotions. It’s also involved in energy production throughout the body. Glutamate excites neural function. Too much glutamate can burn nerves out and too little keeps them from functioning properly. Not only does Brintellix manipulate 5-HT (serotonin), like all other SSRIs, it also manipulates 5-HT1A: Agonist,5-HT1B: Partial Agonist5-HT3: Antagonist 5-HT1D: Antagonist 5-HT7: Antagonist. An agonist triggers a response from a cell. An antagonist does the opposite. It blocks a cell’s response.No one knows what relationship exists between any of these neural receptors and Brintellix’s effect. No one knows what these manipulations of the brain will do to the body, intelligence, emotional state, sexuality, criminality, empathy, or anything in the future.So while it is available, it is not much help past the R&D process.
> -1 votes

# Answer
It sounds like you are interested in the "Quantified self" movement, which deals with self knowledge about one's body function. While this is not a comprehensive answer, there are a few things to consider:

1) Many hormone levels follow **diurnal (24hr) cyclical patterns**, and vary throughout the day. Sleep schedule (wake/bedtime) affects these cycles. This taking single measurements at different times of the day would give you very different results.

An example of sleep pattern (black bar is sleep relative to 24 hr time), wake up times would affect hormone levels at different times.

2) There are **seasonal variations** in hormone levels (for example these control white/brown fur color in animals living around arctic circle). As such, your 3 month study needs to account for the change in seasons, and may be heavily influenced by natural changes.

3)There were a number of startups trying to sell **hormone testing kits** like this one to general public, however these are expensive and "not intended to treat, diagnose, etc". In short, without your own lab, it's really hard for an average person to get this kind of info. A doctor can prescribe a single time test, but those can easily cost hundreds of dollars and are not very descriptive, as the "normal" ranges they give are ridiculously broad (for example testosterone is at range 270 to 1070ng/dl)

4) While it's common to hear popular science refer to "serotonin or dopamine flooding the brain" - ask yourself, where is this flooding occurs? As such, **where do you actually measure these changes**? I still can't find a clear answer to these questions.

My personal research into sleep makes me hypothesize that one can get an impression that something is changing in the serotonin/dopamine/testosterone system by looking at the duration, clarity and content of one's dreams.
> -1 votes

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Tags: cognitive-neuroscience, medication
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# Question
Title: Way to influence readers subconscious to memorize technical data?
I'm writing a technical book. Is there any studies/books on how can I influence the readers subconscious to help them memorize the technical data easier? Preferably ways that do not involve images, styles, etc.. as such techniques are not suitable for technical books.

# Answer
Priming involves the perception of similar elements between information. The similarity between information influences the memory as it has already been primed by previous memory traces.

I do know of a study that suggests that when simple contours of an image are primed before complex versions of those contours, those contours are rated more positively (Reber *et al*., 2004).

The study relates to the theory of processing fluency, which proposes that the visual information is more liked because the information is more compatible than it would be otherwise (if the complex contour was shown without the simple one) that's only one part of the theory. The article is called:

The most simple answer is to relate the information with previously memorized information as it may be more likely to be recalled because it is connected to other memories.

**Reference**
Reber *et al*., Processing fluency and aesthetic pleasure: Is beauty in the perceiver's processing experience? *Personality and Social Psychology Review* ( 2004); **8**(4): 364–382
> 2 votes

# Answer
You can use priming but that assumes that the reader is already familiar with the subject or has read about connected topics. Priming has various aspects but with your requirements you just eliminated the most important ones: images, styles etc. Read more about priming, I am not an expert, there might be more than the above
> -1 votes

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Tags: memory, consciousness
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title: Are mentally ill people more violent?

text:
# Question
Title: Are mentally ill people more violent?
A lot of people are afraid of people with mental illnesses because they think they're more violent but is that true?

I think it's wrong even though I don't really understand the pages I found on google. I found this article from University of Washington which states among other things that "the vast majority of people with mental illness are not violent". I understand this article but it is really short.

# Answer
> 8 votes
'Mental Illness' covers such a broad range of illnesses that it would be very difficult to answer your question. However, general consensus is that: people who are receiving an effective treatment for a mental illness are no more violent or dangerous than neurotypical/ 'healthy' people. People with a mental illness are more likely to harm themselves or to be harmed. There is a weak association between violence and mental illness, especially when alcohol or drug misuse is involved. Early treatment of mental illness is the key to preventing violence. This article covers the topic fairly thoroughly:

Link, B. G., & Stueve, A. (1995). Evidence bearing on mental illness as a possible cause of violent behavior. Epidemiologic Reviews, 17(1), 172-181.

This is from their conclusion on mental illness and public safety:

> People with mental illness pose no greater threat to public safety than do such other "high risk" groups as men or young adults or people with less than a high school education.

# Answer
> 7 votes
There are certain illnesses which are associated with violence, or have aggression as a symptom (which will not always result in physical violence). Especially the Cluster B personality disorders come to mind, with narcissistic rage and crimes perpetrated by people with antisocial personality disorder. Oppositional defiant disorder in children also includes aggression, as well as some addictions like alcoholism.

But these are only a few of the existing mental conditions. Basically, any single system in a human's brain can be messed up, including the ones responsible for aggression. The handful of conditions in which this happens is only a small percentage of all possible conditions. It is not that different from non-mental illness: there are hundreds of diagnoses, but only a small part of them are connected to a specific organ, say, the liver. Most people who suffer from a physical condition do not have a messed up liver; similarly, most people who suffer from a mental condition don't have a messed up aggression control.

If you are concerned with public safety, then it is quite possible that better methods for diagnosing and treating the aggression related mental conditions will result in a society with less violent crime. For example, this study found that 35% of a random sample of prison inmates has antisocial personality disorder, and goes on to mention that it is especially common in violent offenders, while I've seen numbers for the general population estimated at between 1 and 5% (sorry, no citation on that currently present, maybe somebody has better data). So if we knew how to heal people with APD, we could expect less violence in society, as they contribute so much to it.

But if you are concerned with your own personal safety, I would not recommend avoiding people who appear to have a mental illness. The conditions which have the most visible symptoms - the Down child with a creepy smile, the autistic boy who repeatedly jerks his head - are not the ones which are usually connected to aggression. The (potentially aggressive) people with cluster B disorders I mentioned above are hard to diagnose even for specialists, and appear outwardly normal at first. If you are dealing with somebody who has them, you are likely to notice a proneness to aggression which strikes you as unusually high long before you have even thought that this person could have a mental illness. And with some of them, you might not be aware of their condition even after spending years in a close familial relationship with them. So, you cannot use their condition as a heuristic to avoid them, because you are not aware of it at all. If you are on the street and see somebody who reminds you of a caricatural media portrayal of "mentally ill", the risk that he is prone to aggression is not that much higher than that of the normally looking passerbys.

If an acquaintance shares with you that they have a mental illness diagnosis, there is no reason to panic either. Research the specific illness they have so you can better understand it and support them in living with it, for most mental conditions you are not taking any risk for yourself in doing so. And if it is one of the few conditions where they can be violent, the research should easily uncover that, so you can make an informed decision.

# Answer
> 5 votes
Part of the very basic components of abnormal psychology suggests that any behaviour that could be dangerous to oneself or another individual could qualify for a diagnosis for mental illness. But, this is only when other factors are taken into account, for example the presence of dysfunctional behaviour that hinders appropriate functioning in society. (Comer, 2005)

Someone who is mentally ill may be more dangerous than someone who is not. However, you should note that only a small select few mental illnesses involve violence in their diagnosis, antisocial personality, etc.

Most mentally ill people are not violent.

**Reference**

Comer, R. J. (2011). Fundamentals of abnormal psychology. New York: Worth.

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Neurodiverse people may still have the tools to manipulate people just fine. In fact both attention deficit disorder (ADD) and antisocial personalities are theorized to be characterized by propensities of stimulus hunger, as in low arousal theory. (Hare, 1970) This could suggest that ADD and Antisocial personality disorders may share fundamental characteristics.

Note also that Neurodiverse individuals may have issues with executive functioning that may impair social interaction, but also note that between Autism and Attention-Deficit disorder these impairments occur for different reasons. An individual with ADD may have trouble reading social cues because of working memory deficits and inattention. But with Autism it is shown to possibly be due to a difference of semantic processing strategy. (Moseley, 2013), a local processing bias (with global processing not in tact) (Drake, 2010) , as well as working memory deficits.

Neurodiversity covers a wide range of neurological disorders. Autism being one of the most prominent

**Reference**

Hare, Robert D. Psychopathy: Theory and Research: Theory and Research. New York \<\<\[u.a.: Wiley, 1970. Print.

Moseley, Rachel L. et al. “Brain Routes for Reading in Adults with and without Autism: EMEG Evidence.” Journal of Autism and Developmental Disorders 44.1 (2014): 137–153. PMC. Web. 8 June 2016.

Drake, Jennifer E. et al. “\`Autistic’ Local Processing Bias Also Found in Children Gifted in Realistic Drawing.” Journal of Autism and Developmental Disorders 40.6 (2010): 762–773. Web.

# Answer
> -3 votes
I love the way this question is structured. It naturally implies a prejudice and a hatred for those who're mentally disabled, which seems to imply that neurotypical people tend to be more violent.

And that's actually true. There's a history of neurotypicality resulting in greater violence and psychopathy than neurodiversity. The thing is? A neurodiverse person has a hard time being a sociopath because they don't have the tools necessary to manipulate people. So when you think of that person who snaps and goes around killing people? That's a neurotypical extravert.

Look up Ted Bundy and you'll see what I mean. Neurotypicals are far likely to snap and become serial killers. Not just that, but numerous studies have shown that neurodiverse people are far less prone to the kind of prejudices and bigotries that neurotyipcal people can have a proclivity for. Prejudices are especially common in neurotypical extraverts a they prefer to have 'their own kind' surrounding them.

So, no. Not really. If anything, the opposite is true. I feel safer being around neurodiverse people, because I know they won't snap and murder me in the most depraved way.

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Tags: abnormal-psychology, personality
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# Question
Title: Perfectionism, and approval addiction: how are these two generated from a trauma?
Depression and anxiety most of the time stem from a past trauma, but it is actually not the events, but the thoughts that create the symptoms of depression and anxiety.

Out of those thoughts, perfectionism and approval addiction are prominent, and I, myself, am an example of it. So how does a traumatic event tend to generate the cognition of perfectionism and approval addiction, or does it even tend to generate it or is it, itself a result of it(depression and anxiety)?

# Answer
I want to say that this kind of issue is environmental. Behaviours of perfectionism are developed because of certain factors that may stem from early childhood (as in how the parents treat the child). If self esteem is measured based on the standards that the authority sets, but the child cannot reach them, they may come to know themselves as inadequate. Freud talks about this in his theory of psychoanalysis and in the psychodynamic theory.

I don't think it's specifically one case of trauma, but a series of evaluations that causes the development of low self esteem.

Before the child has a complete theory of mind he may not seperate himself from his environment and in turn mirror or internalize the negative image of how his parents treat him. Some evidence suggests that perception becomes more global with age (which may reflect the development of a pragmatic perceptive system that allows faster identification of objects in the environment. ) (Akshoomoff et al., 1995).

Its possible that this global perceptive system may become tied to negative emotional trauma. Which makes negative behaviours more easily developable. Predictions of outcomes of events have also been tied to perception, as perception as been shown to be constructive (in the sense that it builds on itself from past experiences, even emotional ones) (Sinke, et al., 2012)

Individuals who experience abuse may unconsciously recall the outcomes of that abuse during similar situations, causing distress.

Also, some Self theorists may also see the traumatic experiences as negatively affecting the sense of self. Approval addiction may be seen as an act taken to strengthen self identity, as the authority figure did not properly bolster the self esteem during development, so the individual may try to compensate for that by seeking approval.

**Reference**

Developmental trends in visuospatial analysis and planning: I. Copying a complex figure. Akshoomoff, Natacha A.; Stiles, Joan Neuropsychology, Vol 9(3), Jul 1995, 364-377

Sinke, Charlotte B. A. et al. “The Constructive Nature of Affective Vision: Seeing Fearful Scenes Activates Extrastriate Body Area.” PLoS ONE 7.6 (2012): e38118. Web.
> 2 votes

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Tags: cognitive-psychology, depression, anxiety, cognitive-dissonance
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# Question
Title: Is there evidence to suggest that music can trigger release of a particular kind of neurotransmitter?
I've recently listened to a podcast, "The music in your brain", in which Dr. Daniel Levitin suggests that:

* Soothing music can trigger release of oxytocin
* Sad music triggers release of prolactin
* An unknown kind of music triggers release of dopamine.

This may be related to my previous question about "psychoactive music"

**Is there evidence to support the claim that music can trigger the release of specific neurotransmitters in the brain?**

# Answer
> 5 votes
Music is known as a form of an abstract stimulus, which can arouse feelings of euphoria, similar to tangible rewards that involve the striatal (corpus striatum) dopamine system.

In a study, published in nature neuroscience, researchers used the neurochemical specificity of 11C Raclopride positron emission tomography scanning, combined with psychophysiological measures of autonomic nervous system activity, to find endogenous dopamine release in the striatum at peak emotional arousal during music listening. To examine the time course of dopamine release, they used functional magnetic resonance imaging with the same stimuli and listeners, and found a functional dissociation: the caudate was more involved during the anticipation and the nucleus accumbens was more involved during the experience of peak emotional responses to music. These results indicate that intense pleasure in response to music can lead to dopamine release in the striatal system. Notably, the anticipation of an abstract reward can result in dopamine release in an anatomical pathway distinct from that associated with the peak pleasure itself.

Music characterized by genres and musical elements evoke distinct patterns of messenger production.Music of Johann Strauss caused rises in atrial filling fraction and atrial natriuretic peptide and falls in cortisol and tissue-type plasminogen activator (t-PA). Prolactin, cortisol, noradrenaline, and t-PA concentrations decreased after listening to the music of H.W. Henze. Ravi Shankar’s music resulted in lowered concentrations of cortisol, noradrenaline, and t-PA.Listening to techno music was found to alter levels of b-endorphin, adrenocorticotropic hormone (ACTH), norepinephrine , growth hormone, prolactin, and cortisol in healthy people.Critically ill patients who listened to Mozart’s slow piano sonatas had increased growth hormone and decreased interleukin (IL)6 levels.

From the neurochemistry of music by Mona Lisa Chanda and Daniel J. Levitin, Department of Psychology, McGill University, Montreal, Quebec, QC H3A 1B1, Canada

**Disclaimer**: I will keep editing my answer, this is just a start!

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References:

* Krumhansl, C.L. An exploratory study of musical emotions and psychophysiology. Can. J. Exp. Psychol. 51, 336–353 (1997).
* Egerton, A. et al. The dopaminergic basis of human behaviors: a review of molecular imaging studies. Neurosci. Biobehav. Rev. 33, 1109–1132 (2009).
* Dube, L. & Lebel, J. The content and structure of laypeople’s concept of pleasure. Cogn. Emot. 17, 263–295 (2003).
* Sloboda, J. & Juslin, P.N. Psychological perspectives on music and emotion. in Music and Emotion: Theory and Research (ed. Sloboda, J.) 71–104 (Oxford University Press, Oxford, 2001).
* Möckel M, Röcker L, Stoörk T. Immediate physiological responses of healthy volunteers to different types of music: cardiovascular,hormonal and mental changes. Eur J Appl Physiol. 1994;68(6):451-459.
* Gerra G, Zaimovic A, Franchini D, et al. Neuroendocrine Responses of healthy volunteers to ‘techno-music’: relationships with personality traits and emotional state. Int J Psychophysiol.1998;28(1):99-111.

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Tags: cognitive-neuroscience, music
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