# Question
Title: Is a neuron's information processing more complex than a perceptron?
I've been researching the relationship between brain neurons and nodes in neural networks. Repeatedly it is claimed neurons can do complex information processing that vastly exceeds that of a simple activation function in a neural network.

The resources I've read so far suggest nothing fancy is happening with a neuron. The neuron sums the incoming signals from synapses, and then fires when the sum passes a threshold. This is identical to the simple perceptron, the precursor to today's fancy neural networks. If there is more to a neuron's operation that this, I am missing it due to lack of familiarity with the neuroscience terminology. I've also perused this stack exchange, and haven't found anything.

If someone could point to a detailed resource that explains the different complex ways a neuron processes the incoming information, in particular what makes a neuron a more sophisticated information processor than a perceptron, I would be grateful.

# Answer
Even if you fully accept the analogy, a cortical pyramidal neuron's function is best described as that of a multi-layer perceptron, with each dendrite or part of it independently integrating information (Poirazi 2003). In addition, but also because of that fact, the location of connections on the cell plays a crucial role in determining their importance. It just so happens that cortical neural circuits are constructed in a way that exploits this principle (Larkum 2013). Simply put, a real neuron integrates information in time and space, in a way adapted through biological evolution. It does not just lump all inputs together. However, the true marvel --and most of the differences with artificial neural networks-- appears when you look beyond the level of the single neuron: how the neural system specializes and interacts with the rest of the body and the rest of the world, including with other neural systems, actively. Just as food for thought (sic), energy management is of primary importance for neural function and the nervous system is designed around this factor.

---

Response to other answers:

I see many examples in the other answers where people rightly point to phenomena such as neuromodulation and physiological state changes, the topology of the networks, and different learning rates for different neurons. These are to me all valid differences between networks of real neurons and networks of perceptrons. However, I consider it relatively straightforward to adjust the architecture of connectivity or make the learning rate or bias differ between perceptrons to emulate real neural networks. The small adjustments required do not alter a single perceptron's principle of operation. These are some differences that we can observe when looking at networks of many neurons and are beyond the question's scope as I understand it.

The asynchronous updating of weights that @luke-griffiths contributed still concerns the level of many neurons but the adjustment required for perceptrons to incorporate it is a radical move.

I have hinted that there are even more fundamental differences when you look at a level of description beyond the single neuron such as the coupling between neurons and the vasculature, the digestive system, the neuroglia, and the muscles that cannot be copied by networks of perceptrons, simply because they are not attached to a body.

@bonaca listed the existence of electrical synapses which can be considered a characteristic of a single neuron. However, electrical synapses have very specific functionality and are not the main way of information processing in the brain --certainly not in the brain's cortex which I have studied.

It now occurs to me, though, that I and everyone else so far failed to mention another difference between real neurons and perceptrons. Real neurons exhibit metaplasticity due to memory carried by resource allocation (e.g. receptors, structural molecules such as actin, mRNA) or heterosynaptic plasticity (Abraham 2008). To adjust a perceptron to emulate metaplasticity you would have to either make the bias or the learning rate a function of time and/or make each input's weight a function of other inputs' weights. I consider such changes as a major departure from the operating principle of a perceptron, even more so than the spatial sampling I initially mentioned.
> 14 votes

# Answer
Just a couple examples:

## Spatial integration

This is the basis of @vkehayas's answer. More generally, despite integration at the soma being fairly linear up to a point, dendrites are highly non-linear as active conductances (i.e., voltage-gated channels) are necessary in addition to passive ones (i.e., neurotransmitter receptors or experimental current injections). This makes the spatial arrangement of input very important, not just the global sum over all input like a perceptron. See for example:

*London, M., & Hausser, M. (2005). Dendritic computation. Annual review of neuroscience, 28(1), 503-532.*

These spatial arrangements are also critical for distinct forms of inhibitory control of neurotransmission, particularly when people talk about "shunting inhibition" occurring with inhibition out on distal dendrites.

## Short-term plasticity

Synapses are not memoryless; short-term plasticity occurs primarily presynaptically through calcium concentrations. "Weak" synapses (=those with low release probability) tend to show facilitation, as single action potentials do not allow sufficient calcium entry into the presynaptic bouton for release, but over multiple summed action potentials in quick succession the calcium concentration rises and release probability increases.

"Strong" synapses (=those with high release probability) tend to show the opposite, short-term depression, because initial release of vesicles depletes those available to release.

See for example:

*Abbott, L. F., & Regehr, W. G. (2004). Synaptic computation. Nature, 431(7010), 796-803.*

(I'd also recommend Abbott's book with Peter Dayan, "Theoretical Neuroscience" as a good intermediate-level textbook on neural computation; it should be especially accessible if you are familiar with artificial networks)

## Neuromodulation and diverse neurotransmitter actions

While one might take glutamatergic transmission and GABAergic transmission in the CNS and simplify these to a + and - sign, this greatly simplifies things even for just those two neurotransmitters. GABA, for example, will diffuse out of highly active synapses and activate different classes of highly sensitive GABA receptors located far from synapses. Glutamate doesn't just open excitatory channels, but also triggers G-protein receptors on both pre- and post-synaptic cells and can modulate synaptic strength over intermediate time scales.

There's enough complexity with just those two "typical" neurotransmitters before we start to think of other neuromodulators. You could fill library shelves with all the diverse ways that neuromodulators can change the behavior of a circuit. Some of the most remarkable examples are found in what are misleadingly thought of as "simple" nervous systems such as in invertebrates, but similar mechanisms also occur in mammalian nervous systems. Subtle neuromodulation at the level of a single-cell can have massive consequences when viewed at the scope of whole networks; the difference between wake and sleep, for example.

A couple reviews to start with:

*Fellous, J. M., & Linster, C. (1998). Computational models of neuromodulation. Neural computation, 10(4), 771-805.*

*Marder, E., & Thirumalai, V. (2002). Cellular, synaptic and network effects of neuromodulation. Neural Networks, 15(4-6), 479-493.*
> 10 votes

# Answer
I don't know enough about neural networks to properly define the difference between a perceptron and a neuron, I don't know how much machine learning definitions can be expanded or generalized to more fully mimic a biological neuron. But I want to clarify why your assertion that "The neuron sums incoming signals from synapses, and then fires when the sum passes the threshold." is not entirely correct, and certainly not the full picture.

# Neurons integrate information differently

See vkehayas' excellent answer.

# Neurons receive different types of 'input'

1. **A single sensory neuron can sometimes sense multiple types of external stimuli** (e.g. light and mechanical stimuli) and integrate the information (Revilla-i-Domingo et al., 2021)
2. **Chemical synapses** with classical neurotransmitters (e.g. serotonin, dopamine, adrenaline...) - this is what people most commonly think of as 'input', also matches your description I quoted. Even these neurotransmitters can have different functions, like excitation or inhibition.
3. **Electrical synapses**, or gap junctions, where cells are directly electrically coupled.

# Neurons change their behavior depending on physiological state and presence of various molecules

These could arguably be considered another type of input. They can change firing patterns and activation thresholds of neurons.

1. **Neuromodulators** act more slowly, often have a long lasting effect and change how neurons respond to synaptic signals. They are often not released at synapses and often travel long distances. **Neuropeptides** are a very big and interesting category of neuromodulators (e.g. Nussbaum and Blitz). There are at least 65 neuropeptide families (Wang et al., 2015).
2. **Physiological state** modulates neuronal activity (Shetty et al. 2012)

# Activation threshold is variable in biology

Each neuron can have a different threshold potential, and it can change quickly, depending on cell type, physiological state, presence or absence of various neurotransmitters and other molecules.

# Neurons can output different types of information

They may secrete different classical neurotransmitters, neuromodulators, etc. Each type of neuron has the potential to only secrete specific types of neurotransmitters and/or neuromodulators and/or other molecules. If a neuron is activated, it might secrete all types of molecules it has stored, or only one type. It can even release different molecules at different locations (Ghijsen and Leenders, 2005)

# Information transmission between neurons is not straightforward

As explained above, the amount, location and type of 'signal' a pre-synaptic neuron 'outputs' can vary. Conversely, the type, location and amount of 'signal' a post-synaptic neuron receives can also vary. The amount of neurotransmitter present, the distance it has to travel, and how many receptors for that molecule the post-synaptic neuron has will all affect the amount of synaptic 'input' a neuron receives.

# Topology of the network

1. **Every neuron can also send information in the opposite direction, i.e. the postsynaptic neuron sends signals to the presynaptic one** with retrograde neurotransmitters like nitric oxide.
2. **Each neuron is unique**. They receive different types of inputs, they have different axon length, topology and myelination (which changes the amount of time to transmit information), has different types and amounts of receptors for neurotransmitters, external stimuli, etc., they secrete different types and amounts of signalling and other molecules...
3. **Neurons only connect to specific other neurons, and create an incredibly complex network.** To my limited knowledge, in artificial neural networks all nodes in one layer are connected to all nodes in the next layer. There are no such cases in biology.
2.1. Individual neurons can synapse to any number of other neurons (but keep in mind that synaptic transmission is not all there is!). The number of synaptic partners strongly depends on the type of neuron. This is equally true for broad neuron categories like inter- or motoneuron, and for narrower ones like subtypes of Kenyon cells.
2.2. The animal nervous system is incredibly complex, and can't be subdivided into fully separate units. Even the loose arbitrarily defined signalling "subnetworks" (e.g. taste and pain perception pathways) interact with each other in many different ways and many different levels.

Another interesting feature of biological systems are **central pattern generators**.

Finally, as I was searching for some of the references, I stumbled upon this article by Lui et al., which I haven't read fully, but seems to explain how features of biological systems can help improve artificial neural networks and at least partially answer your question.
> 5 votes

# Answer
Yes, a neuron's information processing is more complex than a perceptron's information processing. Here I describe **one** way it's more complex; I am not claiming this is the **only** way it is more complex. (One way is sufficient to answer the question).

A perceptron's "axons" are connected to every one of the perceptrons in the next network layer.

A neuron's axons are connected to many other cells, and those cells do not exist in separate "layers" at all (in some cases the physiology happens to arrange into layers; that's not universal)

Therefore a neuron's information processing is more complex than a perceptron's information processing, because the mixing of its output with that of other neurons' output happens at different "phases".

To see what I mean by phases, consider a perceptron in a neural network. As it processes input, a single input vector is processed all the way through the entire network in a single coherent "wave" of activation (one matrix multiplication performed after another in series). At no point is one perceptron doing its thing while its sibling perceptrons are inactive.

By the terminology I'm using, all of a perceptron's sibling perceptrons' outputs are sent "in phase" to the next layer. So a perceptron's output is always processed in the same "activation environment"; it's always a part of a single type of whole: the set of outputs of its whole layer.

But if two neurons are siblings, i.e. if they both send axons to the same downstream neuron(s), they may or may not send their signals at the same time. Therefore the overall "activation environment" in which its output is interpreted can vary.

An analogy would be a football player who sometimes plays on a small team of 4 players, other times plays on a team of 100 players, and other times plays football as a one-man team. The game that football player is playing is more complex than the game being played by someone who always plays in an 11v11 game.

Insofar as "a neuron's information processing" is the game that neuron is playing, a neuron's game is more complex than a perceptron's game, in the same way that variable football player's game is more complex than the constant-team-sized player's game.
> 3 votes

# Answer
Biological neurons operate with **response latency**, **refraction**, and **inhibition**. It is my understanding that perceptrons do not employ these characteristics.

**Response latency** In biological neurons, there is a delay between the arrival of a super-threshold stimulus and the generation of voltage spike (activation potential). The length of the response latency depends on the intensity, and frequency, of the stimulus. The intensity of the stimulus can my modulated by synaptic connections. Thus, it is the length of this delay that is adjusting in biological learning.

**Refraction time** After a biological neuron fires, it enters its *absolute refractory period*. During this time, it is unable to fire. Biological neurons also have a *relative refractory period*, during which the firing characteristics biological neurons are highly modified.

**Inhibition** The generation of action potentials in biological neurons can be suppressed through inhibition. When inhibited, biological neurons require a greater stimulus in order to generate an action potential.

These three characteristics, among others like bursting and variable spiking modes, distinguish biological neurons and most artificial neurons.
> 2 votes

---
Tags: neuroscience
---


# Question
Title: Choosing Standardized Reading Comprehension Tests to Generalize Results on Active Reading Techniques
We have been designing a series of experiments on comparing different active reading techniques for college students. In most of the studies we found in the literature, the passages are arbitrarily chosen based on the courses that the researchers teach or the topics related to their subject pools.

Are there standardized reading comprehension tests that are reliable and generalizable for college level students? Unfortunately, we could not find any ACT, SAT, AP, or IB reading comprehension tests that are publicly released for research purposes. Passages that cover a variety of topics like humanities, social studies, natural sciences, and literary narratives and similar in length to the ACT long passages are what we are looking for.

If such standardized tests do not exist for researchers, how do you advise we generate such reliable and generalizable reading comprehension tests?

# Answer
The Nelson-Denny reading test has a subtest containing 7 reading passages with normative data for individuals up to 24 years 11 months including 4 year college students with 36 comprehension questions.

Per the Pro Ed website: "Statistical Characteristics

Age-based normative data (N = 4,010) are provided for students ages 14 years 0 months (14-0) through 24 years 11 months (24-11) enrolled in high school, 2-year, or 4-year university programs. Grade-based normative data (N = 3,487) are provided for students of any age who are enrolled in high school, 2-year, or 4-year university programs. The normative samples were stratified to match 2017 U.S. population estimates. For both forms, average internal consistency (content sampling) reliability coefficients range from .85 to .95 (very large to nearly perfect). Average alternate-form reliability ranges from .88 to .94 (very large to nearly perfect). Average test–retest reliability ranges from .89 to .98 (very large to nearly perfect). Correlations with well-known reading measures range from .47 to .84 (moderate to very large). Diagnostic accuracy studies indicate that the NDRT is able to accurately identify students with reading difficulties (sensitivity = .73, specificity = .80, ROC/AUC = .88) with few false positives."
> 2 votes

---
Tags: test, reading, standardized
---


# Question
Title: Is the current approach to AI learning essentially behaviourism?
AI, to the level that we attempt to create it these days, involves creating neural networks that learn from stimulus (experience, data) and reinforcement. A higher score such as in a Go game, or a higher % of matched words, faces or signs seems to equate to positive reinforcement within classical conditioning. Given that behaviourism is mostly seen as somewhat outdated, if the above makes sense, could this model of learning be limiting progress in AI?

# Answer
This is an interesting proposal, but I think is not quite right when we look the definitions at the base.

To start Behaviorism *assumes that **behavior** is either a reflex evoked by the pairing of certain antecedent stimuli in the environment, or a consequence of that individual's history, including especially reinforcement and punishment contingencies, together with the individual's current motivational state and controlling stimuli.*

Form that, we could say that Behaviorism asumes that a group of people, raised on the exact same environment, perceiving the same stimuli (reinforcement and punishment) should grow showing a similar behaviour across time.

Also, *Although behaviorists generally accept the important role of heredity in determining behavior, they focus primarily on environmental events.*

This focus on "environment" per se leaves aside the idea that each individual is unique on its thinking and perception of the world as of their response on a particular event, instead, it tries to define the individual as sort of machine that could be "trained" on a certain way, to act or respond on a deterministic way to a given situation, or in retrospective, act or react in a a way determined mostly, or perhaps only by the environment and previous experiences.

If we accept that our behaviour is entirely deterministic (shaped by stimuli - reinforcement/punishment response), then we could, in theory, teach machines human behaviour quite easily, but this is in essence wrong for two different reasons:

First, I believe the idea that human behaviour is merely deterministic has been debunked many times in the past for more promising theories such as the Big five personality traits for example, which states that each individual personality, or temperament is, on the more primitive sense, determine by biology, although it could be consciously trained. On the big five theory there are a base group of "categories" if you will, that shape personality:

* openness to experience (inventive/curious vs. consistent/cautious)
* conscientiousness (efficient/organized vs. extravagant/careless)
* extraversion (outgoing/energetic vs. solitary/reserved)
* agreeableness(friendly/compassionate vs. critical/rational)
* neuroticism(sensitive/nervous vs. resilient/confident)

Each individual have some of these traits on a lesser or greater degree, and each one of these traits can change predisposition that each individual have to respond to a given situation. For instance a person with "hight" neuroticism can run and hide if notices someone else is chasing them, but a person with ver low neuroticism and maybe hight extraversion can turn around to face the aggressor.

Let's take a different example: imagine everyday on the way to work, you stop by the same bakery to get a muffin, your favourite could be chocolate, and every time the shop is open, you go in to take your chocolate muffin, then one day you see a sign that says "50% off on vanilla muffins", would you take your favourite or would you take the discount?

Who would you respond to this scenario?

Your response can be shaped by your environment, maybe by previous behaviour, or maybe by biology, like a chocolate allergy, if there is such thing, so for each individual you'll have a 50% change to take one or the other, therefor we can argue that it is, at minimum, very difficult to predict behaviour based on previous experience with a 100% accuracy and at the most, that the Behaviourist theory is flaw.

Secondly, **Artificial Intelligence** as we know it today, is not programmable through positive reward and punishment, it works basically based on positive data using a statistical approach.

This is of course an over simplification but it will give you the idea of how different AI is from actually mimicking human behaviour.

Imagine you create an AI that can identify a cat on a picture, to do so, you'll have to provide a ton of data, for example pictures of actual cats, so you'll be "training" the machine to "learn" how a cat looks like, but in fact it uses statistical models at the bottom to measure different aspects like light, shape, size, color, etc. So when presented a landscape picture with a small cat on it, instead of "ruling out" everything that is irrelevant, it will look for a "match", something that looks, on average, similar to the representation of a cat on its dataset; and the larger the sample, the more accurate the model becomes with time.

This approach is not entirely "deterministic" as proposed on the behaviourist field. When you ask to an AI machine "are you sad?", the machine is not reflecting on past experience, emotions, personality traits or anything similar, it is looking for the average response to the same (or similar question) in it's bank of data to give you as an acceptable response.

In response to your original question, yes, the more "deterministic" approach is not the best solution for the AI problem, and it is very limited, this is how most **chat bots** are built, i.e "if someone ask -name- you'll respond -boot-, if someone says jump, you say -no-".

Artificial intelligence, is not even close to "mimic" human behaviour; the machine will learn based on the data you provide to it, it is also a mistake to accept the response of an artificial machine as "human" and treat it as such.
> 1 votes

---
Tags: behaviorism, artificial-intelligence
---


# Question
Title: What's the difference between perseveration and hyperfocus?
Dr. Russell Barkley says hyperfocus goes with autism while perseveration goes with ADHD.

I read that perseveration is the same as hyperfocus or that hyperfocus goes with ADHD.

So what's the difference? Is Dr. Russell Barkley right?

# Answer
> 4 votes
I myself have never found evidence to suggest a difference between perseveration and hyperfocus *when referring to ADHD*. However, while 'hyperfocus' can be a psychiatric or non-psychiatric condition, perseveration is typically considered a psychiatric condition in all instances.

The wikipedia page for hyperfocus has an entire section dedicated to the confusion between hyperfocus and perseveration, particularly as it pertains to ADHD.

> Hyperfocus may in some cases also be symptomatic of a psychiatric condition. In these cases it is more commonly and accurately referred to as perseveration (or perseverance) - the inability to, or impairment in, switching tasks or activities ("set shifting"), or desisting from mental or physical response repetition (gestures, words, thoughts) despite absence or cessation of a stimulus, and which is not excessive in terms of quantity but are apparently both functionless and involve a narrow range of behaviours, and are not better described as stereotypy (a highly repetitive idiosyncratic behaviour).
>
> It is typical for individuals with ADHD to say they 1), can not focus on boring things and 2), can only focus on stimulating things, and that focus is often extreme. Thus it is both a concentration deficit and over-concentration, or generically: "hyperfocus.

# Answer
> 1 votes
Actually,if you saw a few of Dr. Barkley's presentations. He referred to people with autism spectrum disorder as hyperfocus because they focused immensely on fine details of their sensations and their environments. While this hyperfocus, lacks the big picture perception. For instance, the child with autism might focus on the car wheel, while not attending to the car itself.

While perseveration was well defined by the "upstairs" author.

EDIT: Scientists would agree that they have what the ADHD community defines hyperfocus, but some (not all) psychologist/psychiatrist would not appreciate the use of this term based on the definition alone. They would disagree on the word used to define it. They would agree that people with ADHD have perseveration, but not hyperfocus (based on the definition alone). There is science to backup issues related to perseveration. While positive aspects of perseveration is probably lacking in the literature (since that's harder to look for). Hyperfocus would be kept for the autistic symptoms of focusing far too much on one element or detail and not perceiving the remaining of the item for instance.

To make things more complicated, I know there is one psychiatrist who uses the term hyperfocus (although probably not in thescientific literature). His name is Edward Hallowell. He's more of a clinicians and a book writer than a scientist from what I remember.

# Answer
> -1 votes
NOTE: This response is based on my own personal experiences with these kinds of things and also on the information I've gathered online from people who claim to know about the subject (experts). I do not recall specifics, so as to be able to cite every source. Thus, your mileage may vary. :-)

I like words, especially in higher reading levels. However a lot of this quibbling over technical definitions of one condition or another seems to be missing out on what caused the question to arise in the first place.

Perseveration and hyper-focus both can FEEL similar to the casual observer on account of the effects of either symptom making a person behave similarly.

Splitting hairs about what to call it might come from a concern over clearly and consistently identifying the source of what's causing each issue.

So- If I understand correctly:

PERSEVERATION is a general difficulty regulating one's ability to persevere, either for eventually starting or in having trouble with stopping. It is affected or enhanced when the task involves a subject that is particularly stimulating in it's interactions.

It can often feel like a strong motivational inertia regarding task management. Specific stimulating interests can make it easier to start and also harder to stop. This can both work for and against timely task completion, until sufficient supports and accommodations are permitted in order to put that within the reach of the person.

But it sure makes a 12 hour video game marathon easier to do, if a person finds that sufficiently stimulating. Over all, they WANT to try to function, but they can have a tough time making themselves functional on a consistent basis.

HYPER-FOCUS is fixating on a detail or subject specifically. The subject itself is stimulating, even if the activities relating to it might not ordinarily be that engaging to other people.

It doesn't matter if the subject relates to the task at hand, it will definitely, definitely draw the person's attention in a compulsive manner. That's what they want to talk about, study and/or do. If the behavior resulting from the fixation produces something useful, such as an exceedingly niche position of employment, then great! At least they managed to find work, finally.

In extreme cases, until their subject of interest presents itself, they (like the honey-badger) just don't care.

Comorbidity between the two conditions is not entirely uncommon, (overlapping effects from both conditions). The way professional smart people try to argue that both are completely different and there can be no other way might be losing sight of this point.

TO ANSWER YOUR QUESTION: the cause of either condition may be different enough to warrant distinct labels when discussed in a professional medical setting. So I wouldn't be surprised if Dr. Russel Barkley is technically correct. When it comes to fixing a problem, it helps to classify it accurately, rather than just generalize for convenience.

There may even be some people who possess a measure of both conditions, on account of being affected by the separate causes of those conditions at the same time.

Whatever the case, the day-to-day experience is a pension for extreme focus.

Thus the casual inclination of people who are NOT Dr. Russell Barkley is to just call it "hyper-focus" and be done with it. :-)

Hopefully that helps.

---
Tags: abnormal-psychology, adhd
---


# Question
Title: Why do we understand so little about the brain?
Most of the things our brain does we have no clue how it does it. Thought, Memory storage and recall, dreaming, spatial awareness, timekeeping, emotions, pain and the big ONE- qualia. We have no clue how any of these things work and we have studied the brain profusely; scanned it and we got almost zilch. Why is this so? I get the brain is complicated and I agree that consciousness will probably never be explained (possibly ever) but much like the recent papers that a lot of psychology studies are inaccurate; does neuroscience have to be completely re-hauled and restructured if we want to learn the truth?

https://alleninstitute.org/news-press/articles/lab-notes-why-dont-we-understand-brain

# Answer
> 3 votes
"*does neuroscience have to be completely re-hauled and restructured (...)?*"

I would leave aside the (over) exaggeration that "*We have no clue how any of these things work*", and would replace the way too ambitious (and ill defined) objective of "*if we want to learn the truth*" by a more reasonable one such as "*in order to achieve critically higher levels of understanding*".

What has been pointed out by researchers in "complex systems" (which range from ecology to psychology) in the last decades is that **the "divide and conquer" approach to science** (e.g. separate the study of brains between neurology and psychology) might have been extremely useful to human societies in understanding many aspects of the universe, but **might have inherent limitations** for studying and understanding properties emerging from large complex systems (e.g. understanding how a transistor works is at a different level from understanding how a computer works), for which a more "holistic", an understanding at a higher level, might be required.

Such limitations might not just be inherent to the approach, but to the capacities of the human brains or human individuals in general: whether we reached such limits or not already, it is clear that there are limits to how much scope and depth a human individual can achieve about any specific topic in a human lifespan. Such argument has been used by science fiction authors to predict that future breakthrough in complex systems (including topics such as "*understanding how the brain works*") will be achieved by (radically) augmented humans (considering that we are already augmented) and/or artificial intelligence. (I think that this is one of the central argument of trans-humanism, but I am not an expert on the topic.)

Note also the amusing recursive component of the issue of "understanding the brain": if you have to "extend" the brain in order to understand it, your target is moving, and you might have to extend further your "old brain" in order to understand the "new brain". The issue is way more complicated and not as paradoxical as it seems, but amusing (and with a little bit of truth in it) nevertheless.

In short,

* I am convinced that neuroscience can still make serious progresses in the understanding of "how brains work" with the current technology and knowledge; but
* I have no doubts that some (far in the future) future breakthroughs will require a re-haul, a restructure, and even a breakthrough in the augmentation of humans itself. Whether such event will come sooner or later I cannot fathom.

Hope it helps!

# Answer
> 0 votes
I would just point out that after reading a piece about the future of neuroscience over next 50 years, what became apparent was that there where still a lot of various levels of study from the cellular level on up to how they grow and develop and become larger networks and then further the brain. Like they are still trying to figure out and tease apart the entire bottom up, and the. Top down model. They know a lot. One limiting factor though too is to actually build an accurate model of the brain it would require an absolute insane amount of computing power. Like nothing short of a powerful quantum computer could do this. Even then it might be a lot, especially if you add the rest of the body. Not being able to create these models does keep them from doing a sort of “guess and check” type of experimentation.That would allow us to learn at a faster rate. Also even if we could make the models, they still are trying to connect the absolute bottom level to the top in terms of development and functional integration. The article I read did none the less describe a rather exciting future in neuroscience as the field is able to close certain gaps in understanding, one after another, so progress is coming. But know this, the US invests 2/3rds the amount of money in basic research that China does. If we want to stay strong we need to invest in this type of research which has been proven in past to generate roughly $10 for every $1 invested in long run. It’s just inherently the messy type of research that you can’t require a ROI right away. Some fields take time to develop, others not as much. But the more we inch forward to learning and growing where ever it takes us, the more economic prosperity answer strength we can project as a country going forward. Like to be fair, something with a ROI of 10:1, this is by definition worth it even as deficit spending.

---
Tags: theoretical-neuroscience, experimental-neuroscience
---


# Question
Title: What disorder might be considered opposite of the Histrionic Personality Disorder?
If a person might be considered the opposite of Narcissistic or having a Histrionic Personality disorder, what might it be called?

For example, a person who feels a need to be unnoticed.

Of course, I mean "disorder" in the sense that these qualities are "disruptive" to a healthy lifestyle...

Maybe some sort of insecurity disorder? Can anti-social disorders somehow fit? What about situations perhaps stemming from PTSD?

> Don't be a target!" -Every military branch, (except maybe the Army).

# Answer
> 6 votes
Diagnosis of personality disorders in general is moving away from a categorical system (patient does or does not have the disorder), to a dimensional system (patient scores extreme on personality traits). In this system, labels such as HPD and NPD will eventually be deprecated.

The categorical system maps onto scores in the dimensional system as illustrated by this chart (based on the DSM-IV-TR, an older version of the standard diagnostic manual in North America):

To find the "opposite" (counterpart) of a personality disorder using this chart, just look for a disorder that is red (low) where the counterpart is green (high), and vice versa. For HPD, it looks like AvPD (Avoidant Personality Disorder) is a close match.

---
Tags: personality, abnormal-psychology, personality-disorder, diagnosis, dsm
---


# Question
Title: Evidence of cannabis exposure causing schizophrenia?
I've heard that cannabis exposure during teenage years increases the probability of developing schizophrenia-like symptoms later in life. What evidence is there that this is causal and not correlational?

Current references I'm reading and will try to form into an answer:

# Answer
> 2 votes
I discovered a study relating to a **longitudinal study** of a cohort of 45 570 Swedish conscripts covering a 15 year difference in between the first testing of and after. They covered the Swedish conscripts who had taken cannabis ( Who used cannabis on more than '50 occasions' ) and the others who haven't and came to the conclusion that the subjects that taken cannabis had a higher likelihood of developing schizophrenic symptoms than their counterparts. In their own words,

> "Persistence of the association after allowance for other psychiatric illness and social background indicated that cannabis is an independent risk factor for schizophrenia"

The study is here: https://www.sciencedirect.com/science/article/abs/pii/S0140673687926201

---
Tags: abnormal-psychology, psychopharmacology
---


# Question
Title: What is a formal word or term for forgetting what you were doing or saying while doing or saying it?
While running downstairs to do something important, I notice how sunny it is outside, and by the time I reach the bottom of the stairs I forgot why I ran down the stairs in the first place! Or I’m in the middle of a sentence trying to explain something, and all of a sudden forget what I’m trying to explain. I’m not asking about tip of the tongue or an inability to remember someone’s name, because the thought or names were already thought of a few seconds earlier.

I usually remember a few seconds or minutes later, and sometimes it takes much longer, or I don’t remember at all. I’m pretty sure this happens to everybody; what is the term or word that describes this? **I’m specifically trying to separate what is ordinary from what is abnormally progressing.** It’s not Lethologica or Lethonomia.

There are a lot of good suggestions to replace the term, ‘brain farts,’ like a mental lapse or senior moment, but I’m looking for a more formal term like Lethologica or Lethonomia.

Sentence example would be:

I’ve experienced \[word/term\] throughout my life on occasion, but the recent frequency has me concerned something is wrong or I need to change something in my life.

I’ve experienced a lot of \[word/term\] lately so I wonder if I need to get more sleep or it’s something more serious.

# Answer
I think "brain fart" is the best choice of word and no better one exists.

Some may call it an **executive dysfunction** rather than an STM loss.

* example 3. easily distracted.

## Anecdotal

I am 70 and have a similar experience.

1. A doorway might never be in the path or cause for memory loss, but minimal distraction with a short change in time and/or space is needed.
2. The memory is well stored, it's just you forget where you stored it, because of some distraction.
3. It is a normal progressive short-term memory aging issue. I am working on something but need to find a different tool in the garage or the basement. I rush over there and immediately forget what I was looking for. So I have to retrace my steps to the problem at hand and what special tool I needed to fix that. Then I remember.
4. But when I shop for different groceries. It is no problem. I just have to remember the number of items I need and then I know where the items are stored.

> so I wonder if I need to get more sleep or it is something more serious.

* There are many healthy ways to slow the progress, walking 5 miles a week, Vit B12, good sleep, avoid intake of harmful stuff, exercise the planning part of your brain with focus on execution
> 3 votes

---
Tags: working-memory
---


# Question
Title: Why does EOG (eye EEG) spike and fall back down when you look to one direction?
Why does EOG (eye EEG) first spike and then immediately fall back down when you look to one direction instead of staying spiked and only falling back down when your eyes go back to neutral?

From what I understand the corner (front of eye) is positive while the retina (back of eye) is negative. So if I have electrodes on each temple and I look left I would expect the EOG graph to spike (or dip depending on the electrode placement) and stay up until I move my positive cornea away from the left electrode.

**Video explaining EOG**

But instead the graph spikes and then dips back to neutral even though my positively charged cornea is still close to the left electrode since I have not returned my eye back to neutral.

To be clear this graph ***is correct*** I just don't understand ***why***.

**Ex: In the picture below I am holding my eyes left until I look right. But for some reason the graph immediately drops back to neutral even though I'm still looking left.**

**Ex 2:** Here's a video of a live EOG recording and a person moving their eyes showing the same graph behavior.

# Answer
> 3 votes
If you had an EOG signal in a perfect world, it would show constant deflections based on how far the eyes are directed left/right.

In the real world, measuring any electrical signal is quite difficult; there are lots of interfering signals.

My *best guess*, without further methodological details, is that the equipment here is using a *high-pass filter* (almost certainly a band-pass filter, but the high-pass part is the part you're asking about; the low-pass part is the reason the deflections are so smooth and slow). This removes slow drift that you expect to find when you record electrical signals and for a static signal will give you a nice, constant "0 V". However, if you hold your eyes at some deflection, that gets filtered out, too. Here's what high-pass filtering does to a square-wave signal:

The input signal, in red, steps up to 5V, but then stays constant; the high-pass filter returns this constant deflection towards 0V (blue trace). Then when the input steps back down to 0V, the output is a negative deflection, which again returns towards 0V as the input stays constant. In other words, a high-pass filter turns the circuit into a *change detector*.

This paper:

Ryu, J., Lee, M., & Kim, D. H. (2019). EOG-based eye tracking protocol using baseline drift removal algorithm for long-term eye movement detection. Expert Systems with Applications, 131, 275-287.

discusses some of the types of baseline drift you might expect (figure 2) vs. how the signal would look in an ideal world (figure 1):

They propose a particular algorithm to help deal with this, but in any event, it seems the device you're looking at is suitable for a "cool, I can detect the movement of the eyes!"-type home experiment; it's not suitable without substantial upgrades to processing the signal to actually identify the current position of the eyes.

It looks like the directions posted here recommend using a bandpass filter from 1-100 Hz. A constant signal is a "DC (direct current)" or "0 Hz" signal, so it's not in the passband and gets filtered out.

# Answer
> -1 votes
I captured the same signals in 1974 during Biomedic Engineering demonstrations during a festival at U of M.

I attributed that to **\[galvanic skin response\]\[1\]** **due to progressive differential temple pressures on the electrodes due to eye muscle tension.** Given a constant charge Q = CV in each electrode as the differential pressure changes so does the capacitance change incrementally and the voltage decreases incrementally (the absolute value does not change polarity, just the delta V). By watching girls walking left and others right, I was able to make a linear triangle waveform. Applying slight pressure had the same effect.

With a slow AC response (0.1Hz) one might be able possibly to calibrate it in vertical and horizontal directions with 4 electrodes. If there was a need one might possibly find a useful prosthetic use for quadriplegics.

Your experimental equipment must have been a faster return to 0V such as a 1Hz cutoff. A step motion 10 to 90% fall time indicates your cutoff. , Tr = 0.35/ f-3dB is an easy way to estimate bandwidth for either LPF or HPF. \[1\]: https://www.ihtbio.com/galvanic-skin-response-gsr/

---
Tags: eeg, electrophysiology
---


# Question
Title: Are there methods of evaluating the effects of psychoactive drugs that use free-form verbal reports?
If one wished to study the effects of a psychoactive drug such as LSD, what strikes me as a natural primary starting point would be to ask participants what they actually experienced. For example, they could write a page in response to a simple question about what the experience was like.

The results could then be analyzed using an approach such as natural language processing, to find common themes in reported effects. This analysis would then be open to peer-review and replication.

Is this a method of research that anyone currently practices in psychology?

# Answer
In terms of measurement methodology, research is divided into the standard quantitative, and alternative, qualitative research:

> Qualitative research relies on data obtained by the researcher from first-hand observation, interviews, questionnaires (on which participants write descriptively), focus groups, participant-observation, recordings made in natural settings, documents, case studies, and artifacts. The data are generally nonnumerical. ... Qualitative research methods have been used in sociology, anthropology, political science, psychology, social work, and educational research.

Examples of techniques within the field of qualitative psychological research that are applicable to the study of psychoactive drug experiences, include thematic analysis (TA):

> ... one of the most common forms of analysis within qualitative research. It emphasizes identifying, analysing and interpreting patterns of meaning (or "themes") within qualitative data. ... Coding is the primary process for developing themes by identifying items of analytic interest in the data and tagging these with a coding label. ... there is a long tradition of using thematic analysis in phenomenological research. A phenomenological approach emphasizes the participants' perceptions, feelings and experiences as the paramount object of study.

And interpretative phenomenological analysis (IPA):

> ... an approach to psychological qualitative research ... that ... aims to offer insights into how a given person, in a given context, makes sense of a given phenomenon. ... One might use IPA if one had a research question which aimed to understand what a given experience was like (phenomenology) and how someone made sense of it (interpretation). ... After transcribing the data, the researcher works closely and intensively with the text, ... the researcher catalogues the emerging codes, and subsequently begins to look for patterns in the codes. These patterns are called 'themes'. Themes are recurring patterns of meaning (ideas, thoughts, feelings) throughout the text.

Other common techniques that employ the analysis of free-form verbal reports include the thematic apperception test (TAT), and computer-aided text analysis (CATA). However, due to the nature of the phenomenology of psychedelics, it is also common to use a hermeneutic (interpretive) approach in that particular sub-field, rather than a thematic one.

For the example of what psychedelic experience is like, qualitative methods were more common in the early history of psychedelic research - "The Varieties of Psychedelic Experience" by Masters & Houston (1966) is a book full of free-form verbal reports collected and analyzed for this purpose. For more modern examples using qualitative methods to evaluate psychedelic experiences, see this list of papers from 2014-2019, using primarily TA and IPA (source: Breeksema et al, 2020).

I would speculate several reasons why qualitative research is less common in psychedelic research today than it was early on:

* Qualitative methods are useful in basic research for generating more specific research questions. As the effects of psychedelics on experiences are quite well-known by now, the need for such research has declined.
* As with most psychoactive drugs, psychedelic research is mostly focused on its potential therapeutic value, where quantitative methods are required for regulatory approval.
* Psychedelics remain tightly controlled substances, limiting funding for basic research on questions that do not have direct practical applications.
* Even in the relatively small sub-field of psychedelic research interested in experience (eg, to learn about how the mind works), quantitative methods are often preferred as they are less time-consuming (costly) to administer, and less challenging to validate, relative to qualitative ones.
> 1 votes

# Answer
I think to publish a subjective approach as you describe here in the scientific, peer-reviewed literature is going to be difficult. For one, people may have wildly differing subjective experiences to psychoactive compounds, and even within-subject experiences can differ on a day-to-day basis, dependent on mental well being, amount of sleep, ingestion of other active compounds, state of mind etc. Further, the legal status of psychoactive substances greatly inhibits research in the field. There is ongoing research despite regulatory restrictions, yet the main focus of these studies on psychoactive substances like MDMA are their use as treatment for mental ailments such as PTSD and depression (Griffiths & Grob, 2020).

Nonetheless, I think reporting subjective experiences to hallucinogens and related compounds is an interesting approach. It can hold scientific potential, especially when you start classifying and categorizing subjective experiences as you suggest.

A good place to start reading on documenting subjective experiences during and after the ingestion of psychoactive compounds are the works of the late **Alexander Shulgin**.

<sub>**References**
**-** Griffiths & Grob, *Sci Am* (December 2020 issue)
**-** Shulgin & Shulgin, PIHKAL: A Chemical Love Story. Transform Press (1991)
**-** Shulgin & Shulgin, TIHKAL: The Continuation. TransformPress (1997)</sub>
> 1 votes

---
Tags: measurement, methodology, experimental-psychology, psychopharmacology, drugs
---


title: Psychological effects of social nudity

text:
# Question
Title: Psychological effects of social nudity
I have been conducting extensive research over the last few years on the history of nudity in social situations, and I am looking to expand my research base now I have come across a few other interesting facts. I have found a lot of facts stating that although the wearing of clothes is the social norm in most cultures; some cultures, groups and individuals are more relaxed about nudity (for example Nudists/naturists \- **WARNING! - Link is NSFW**), however, attitudes often depend on context. It is generally agreed by naturist organisations (for example, British Naturism and International Naturist Federation) that eroticism and blatant sexuality have no place in naturism and are, in fact, directly opposed to its ideals. Reasons that have at times been given include rapport with other humans including equality and respect.

> Being nude in groups makes all feel more accepted – physically, intellectually and emotionally (Veltheim, 2010)

On the other hand, some people feel uncomfortable in the presence of any nudity, and the presence of a nude person in a public place can give rise to controversy, irrespective of the attitude of the person who is nude. You only have to look at the history of Steven Gough as an example.

Besides meeting social disapproval, in some countries and in some settings within more liberal countries, public nudity may constitute a crime of indecent exposure. Many people have strong views on nudity, which to them can involve issues and standards of modesty, decency and morality. Some people have a psychological aversion to nudity, called gymnophobia.

On the flip side, there is a form of psychotherapy I have not long come across called Nude Psychotherapy which is

> the use of non-sexual social nudity as an intentional means to improve the participant's psychological health.
>
> The field began in the 1930s with psychological studies of the effects of social nudity on the lives of naturists. It developed in the 1960s along with the encounter group movement as a way to challenge preconceptions and promote intimacy and trust, but suffered a decline in the 1980s. It is still used by some organizations that offer participatory workshops on intimacy, sex and love...
>
> ...Today The Human Awareness Institute (Global Site) (UK Site), an organization that offers participatory workshops on intimacy, sex and love continues to conduct group sessions in which the participants have the option to be naked. (Shewey, 1994)

There are a lot of historical studies on the history of clothing, social nudity, and nudity in art, ancient Greece and ancient Rome; plus there are also anthropological studies on the irony of losing fur when evolving from primates (Horizon: What's The Problem With Nudity, 2008). I am not after biblical references (I have lots of those through my research) and **I am not after personal opinions without scientific backing**. What I am wondering is **are there any referenced books, articles or scientific studies anyone is aware of, on the psychological effects of nudity - particularly social nudity**?

## References

Horizon: What's The Problem With Nudity, (2008) \[Film\] Directed by Paul King. UK: BBC. Available on YouTube

John Veltheim, (2010). *Naturism: Naked Beneath Your Clothing*

Shewey, Don (1994). *Healed With a Kiss*

# Answer
> 4 votes
Quoting from one paper, which doesn't say all that much:

> The experience of nakedness under the gaze of others is highly diverse, and important background differences will affect the relative comfort with which one might strip in front of others.

Cover, R. (2003). The naked subject: Nudity, context and sexualization in contemporary culture. Body & Society, 9(3), 53-72. DOI: 10.1177/1357034X030093004

And from one of the few studies of nudists in the US, back when this was more common over there (that is 1964):

> Among changes reported by nudists were “less concern with appearance,” “reduced anxiety,” “more benevolence,” and “less inhibition.”

Casler, L. (2010). Some Sociopsychological Observations in a Nudist Camp: A Preliminary Study, The Journal of Social Psychology, 64:2, 307-323

Fairly similar findings from a nude group therapy "marathon" (24hrs session):

> Nudity apparently facilitates group interaction in a marathon. 17 of 20 participants felt that the factor of nudity increased their ability to open up to each other emotionally and to achieve a greater degree of authenticity and transparency. The group integrated and seemed to become therapeutically functional more rapidly than clothed marathon groups

Bindrim, P. (1968). A report on a nude marathon: The effect of physical nudity upon the practice of interaction in the marathon group. Psychotherapy: Theory, Research & Practice, 5(3), 180-188

And a pretty interesting discussion contrasting the German and UK cultural differences in how sexuality relates to social nudity is found in Smith, G., & King, M. (2009). Naturism and sexuality: Broadening our approach to sexual wellbeing. Health & place, 15(2), 439-446.

# Answer
> 1 votes
There's this article which I'm unable to obtain: "The Psychology of Social Nudism", Lutzeier, Daniel Paul

https://www.base-search.net/Record/24284d994ab352ffa7c0fe41386604322d9cd0edfc2a04f7082ffbcac2beadd2/

# Answer
> 0 votes
For the psychology of small groups of people, we have for example:

The Social Psychology of Behaviour in Small Groups By Donald C. Pennington

---
Tags: cognitive-psychology, social-psychology
---


# Question
Title: How can someone enjoy something without dopamine?
In this video, Andrew Huberman says people and even animals with depleted dopamine levels can still enjoy stuff.

How does one enjoy without dopamine? Isn't it the pleasure chemical?

Can serotonin, oxytocin etc. contribute to pleasure experience like dopamine?

# Answer
> 5 votes
It is oversimplifying things that a single compound mediates complex human behavior. To nuance things a bit, there are more neurotransmitters and modulators that mediate feelings of pleasure, as you already indicate.

* **Dopamine**, indeed, is associated with feelings of pleasure, and most notably that in response to reward. It also mediates reinforcement, and unfortunately the euphoria associated with addictive dopaminergic psychoactive drugs, like heroine and cocaine.
* But there are more neurochemicals mediating pleasure, such as **serotonin**, that is increased after working out ('runner's high') and after exposure to sunlight, for instance.
* **Endorphins** are a group of protein neuromodulators with a diverse set of functions, from killing pain to the feelings of bliss after sex.
* Lastly, there is **oxytocin**, the 'love' hormone. We produce oxytocin when we’re excited by our sexual partner, and when we fall in love. So there is more to pleasure than dopamine alone.

What you are referring to, an absence of pleasure, is referred to as **anhedonia**, this is not simply due to an absence of dopamine, but is one of the possible symptoms of depression and other mental illnesses, like schizophrenia and bipolar disorder. It can even show up with Parkinson's disease, diabetes, coronary artery disease, and in substance abuse. While schizophrenia and Parkinson's are intimitely linked to dopamine, others are, apparently, not.

---
Tags: neuroscience, neurophysiology, dopamine, serotonin
---


# Question
Title: Are binary relations the same as "1-dimensional"?
Halford et al. (2010) claims discusses binary relations and that humans can process up to a *quaternary* relation. Are these equivalent to "0-dimensional," "1-dimensional" relational reasoning problems discussed elsewhere?

For example, a binary relation discussed in that paper, *taller(Bob, Tom)* involves comparing one dimension: height, so it could be a 1-dimensional problem, yet I can't find confirmation of the terminology.

# Answer
> 2 votes
**In Short:**

I am not sure what "0-dimensional" relational reasoning problems would be, but in mathematics, a binary relation is usually referred to as two-dimensional, a ternary one as tri-dimensional, etc, mostly because of their matrix representation in the same dimension.

**Longer answer:**

A binary relation associates elements from two domains ('domain' and 'co domain') via a set of ordered pairs. You can represent it as a **two dimensional array** of boolean value where one writes `True` in row $i$ and column $j$ if and only if $(i,j)$ is in the relation.

By extension, a ternary relation or any finitary relation (of which a quartenary relation would be a particular case) associates elements from $t$ domains (where $t=3$ for a ternary relation) via a set of $t$-uples, and you can represent them as $t$-dimensional arrays of boolean values

---
Tags: terminology
---


# Question
Title: In the face of sexual trauma, do sufferers tend to avoid relationships with the other sex?
People who suffer trauma tend to avoid talking about their traumatic events: I am wondering if this happens in sexual trauma.

My concern is that the brain should not evolve features leading to the avoidance of sex, because practicing sex is a primary evolutionary advantage (e.g. it is the second level in Maslow's Pyramid).

* Does the brain fail to adopt the most efficient genes replication tendency or
* is the brain's reaction in such a context an exception to the typical trauma response in other contexts?

# Answer
**SHORT ANSWER:** The fact that victims of sexual trauma would tend to avoid sex because it is associated to their trauma would *not* be contradicting evolutionary theory. Natural selection is strong, but it is not omnipotent!

**LONGER ARGUMENT:**

* Many trauma reactions are counter productive, evolutionary speaking: Take any victim of any trauma, who might be showing any kind of post traumatic disorder: the behaviors induced can be self-harming and anti-social, and are often counter productive in term of survival and reproduction, and are counter selected by natural selection.
* Saying that "X should not exist, because it is counter productive, evolutionary speaking" is akin (apologizing for the caricature here) to say that your arm should not break when you fall from a cliff, because it is not helping you to survive and/or to reproduce, so natural evolution should have selected for stronger arms in humans.
* Any feature has advantages and drawbacks, and evolution is about balancing those two sets: Having stronger bones might require more nutrients to build them and to move a heavier body. A better resilience to sexual trauma might mean less emotional sensitivity.
* And if some contexts (e.g. falling from a cliff, being abused sexually) occurs with a low enough probability, natural selection will *not* select for paying the price to better react to those contexts.
> 1 votes

---
Tags: trauma, sexual-assault
---


# Question
Title: What is the purpose of having both a ground electrode and a reference electrode in EEG setups?
In almost all electroencephalography (EEG) recording setups, there are two auxiliary electrodes in addition to the ones used to record: the ground electrode and the reference electrode.

I've so far read two explanations for this. First, the explanation provided here is that the ground electrode is used for active grounding in a driven-right-leg (DRL) setup, so as to eliminate the common mode and thus increase the common mode rejection ratio (CMRR). Second, the explanation provided here is that to measure voltage, we need a signal ground, and that an electrophysiological signal only makes sense as the difference between two sites with non-zero value.

The first explanation does make sense to me, but the second one doesn't: can't you just measure everything as the difference between the site and the ground? The two seem quite contradictory...

# Answer
> 0 votes
To record good clean EEG signals in the microvolt range, you need to eliminate as much noise as possible. Since voltages are recorded as potential differences, you need at minimum 2 electrodes to see anything at all; one reference and one signal sensor.

But you don't *need* a ground to use this data. You can very simply record EEG with only 1x signal and 1x ref, but it will be extremely noisy.

In EEG recordings with 1 each signal, ref, and ground, you make 2 subtractions.

1. REF - GND
2. SIGNAL - REF

subtraction #1 removes common mode signal. The human body is an antenna, and can pick up ambient interference. This is subtracted away from the REF signal, to provide a "cleaner" baseline.

subtraction #2 provides your biopotential signal against this clean baseline REF signal.

If you record SIGNAL - GND only, you would have a potential difference which includes microvolt - volt range noise in addition to the neural signal of interest. This means the signal-noise ratio would be very low, to the point where artifact rejection and computational correction methods would be almost useless.

PyCorder, which is python based recording software from BrainProducts, actually allows you to do authentic ground-free recordings. But nobody uses this function, because nobody needs it.

The double subtraction allows for cleaner, mostly ambient-noise-free signal to be recorded at signal channels. This is also why impedance reduction is important.

This is the reasoning behind REF + GND montages in EEG recordings.

---
Tags: neuroscience, eeg
---


# Question
Title: Doubt about zero-crossings detection in the visual system
I'm currently reading the excellent book "Vision" by David Marr. In chapter 2.2 (ZERO-CROSSINGS AND THE RAW PRIMAL SKETCH), he explains a possible model for the physiological detection of zero-crossings. As *zero-crossing* we mean the locations of the image where the laplacian is zero (that represents a sudden change in intensity, i.e. an edge)

From Marr's book:

> From a physiological point of view, zero-crossing segments are easy to detect without relying on the detection of zero values, which would be a physiologically implausible idea. The reason is that just to one side of the zero-crossing will lie a peak positive value of the filtered image ∇2G * I, and just to the other side, a peak negative value. These peaks will be roughly w2–D/ apart, where w2–D is the width of the receptive field center of the underlying filter ∇2G. Hence, just to one side, an on-center X cell will be firing strongly, and just to the other side, an off-center X cell will be firing strongly; the sum of their firings will correspond to the slope of the zero-crossing—a high-contrast intensity change producing stronger firing than a low-contrast change. The existence of a zero-crossing can therefore be detected by a mechanism that connects an on-center cell and an off-center cell to an AND gate,\* as illustrated in Figure 2–18(a).

Marr, David. Vision (pp. 93-94). MIT Press. Kindle Edition.

I'm not quite able to fully understand why this would make sense since

1. The receptive field of P (on-center ganglion cell) is stimulated even on its periphery (and this would reduce its firing)
2. The receptive field of Q (off-center ganglion cell) isn't stimulated on its periphery (and this would reduce its firing too, right?)

This is the kind of stimulus I guess it's being represented by the book:

Are these reasonable doubts or did I not fully understand Marr's model?

To note, in this video by Nancy Kanwisher from MIT, she explains a physiological model for edge detection (not necessarily zero-crossings detection) in a different way which makes way more sense to me:

# Answer
> 1 votes
> What I understand from the book and the figure (and I may be wrong) is that everything on the left of the bar is white (stimulus is present) and everything at the right of ithe bar is black (no stimulus).

Yes, I believe this interpretation is correct.

If everything left/above the bar is white, P is on, because there is light on its center and it's an on-center cell (=active with light on center). If everything right/below the bar is dark, Q is on, because there is dark on it's center and it's an off-center cell (=active with dark on center). This tells us there is an edge here.

I think you're probably overestimating the importance of the surround here, or not appreciating that neurons can have a range of activity levels, where even small changes in activity are useful and meaningful in the brain. With the edge across the receptive field of P, P is going to fire more than it would if the entire cell was illuminated; as drawn, part of P's off-surround is not getting light. Same for Q, if all of Q was dark, it would fire less than in this situation, where part of Q's on-surround is illuminated, while its center is dark.

If you have a bunch of these cells, like in (b), you can easily see the extent of the edge.

---
Tags: neuroscience, cognitive-neuroscience, vision
---


# Question
Title: Is it possible for someone to not remember something, but to remember that one used to remember it?
Is it possible for someone to forgot an incident or memory, yet still remember that one used to remember it? If so, can someone give me an example?

# Answer
> 2 votes
I don't know if this is the kind of situation you're looking for, but doesn't the classic 'walking into a room and forgetting why' qualify? You remember that you had a task you set out for, you started that task by walking into the room, but now you can't remember what the task was. It might not quite be right because you're in the middle of the task, so "remembering" might not be the right word for those specific instances, but I've had similar occurences more than once where I suddenly remember there was *something* I was supposed to do, but it can take quite some time to remember what it was if the memory comes back at all.

It reminded me of this scene https://youtu.be/9HXeRx828gM as well, so I don't think it's only me that's had that experience :D

*I can't help but chuckle at the fact I just linked a 2 and a half men clip in an answer about psychology*

---
Tags: memory
---


# Question
Title: Is there any medication which is molecularly similar to alcohol?
I have found alcohol to have beneficial and desirable effects on me, and I have been exploring the question of why alcohol is not given the same level of pharmaceutical legitimacy as other medicines and medications.

For example, is there even any research being conducted on what beneficial psychological effects the consumption of alcohol may have?

Or, more importantly, is there any medication which is a molecule similar to alcohol, with moderately similar effects?

Which medication is most molecularly similar to ethanol? It is part of the class of compounds known as "alcohols" - the only alcohol I know to be used as a medicine would be paracetamol.

# Answer
> 1 votes
As far as I know, alcohol (ethanol) is sometimes used as a medication in methanol poisoning (Jones, 2021), and of course also as a disinfectant.

While alcohol in low doses has some positive effects (for instance decreasing anxiety, reduced time to sleep and also perhaps also some cardioprotective effects though this is disputed), the side effects and negative long-term health consequences are much more prominent. In fact, more and more experts on the topic seem to hold the view that there is no safe level of alcohol consumption so with that in mind, using alcohol as a medication when there are other, much safer options, seems like a bad idea (Topiwala, 2021).

Alcohol might have "beneficial and desirable" effects on you - for now. However, there are very real risk of addiction and a multitude of physical health risks down the line.

Regarding your question about similar substances, there are a class of drugs called benzodiazepines. They are not structurally similar to alcohol, but their mechanism of action mimics the main mechanism of action of alcohol, which is increased signalling of GABA-ergic neurons in the central nervous system. In fact, alcohol and benzodiazepines are cross reactive, which means that benzodiazepines can and are used in the treatment of alcohol withdrawal. Benzodiazepines share the effects of alcohol on anxiety and sedation, and are used for anxiety and insomnia.

However, while less harmful than alcohol in many ways (Nutt et al, 2010), benzodiazepines are also highly addictive and should preferably not be used as a continuous treatment.

I hope this answer helps you.

References (as suggested by another user in the comments):

Jones AW. Clinical and forensic toxicology of methanol. Forensic Sci Rev. 2021 Jul;33(2):117-143.

Nutt DJ, King LA, Phillips LD; Independent Scientific Committee on Drugs.Drug harms in the UK: a multicriteria decision analysis. Lancet. 2010 Nov 6;376(9752):1558-65.

Topiwala A, Ebmeier KP, Maullin-Sapey T, Nichols TE. Alcohol consumption and MRI markers of brain structure and function: Cohort study of 25,378 UK Biobank participants.

---
Tags: psychopharmacology
---


# Question
Title: what is a layer in a **biological** neural network?
in this book Computational Cognitive Neuroscience and its corresponding software leabra

> The Leabra Algorithm: Leabra stands for Local, Error-driven and Associative, **Biologically Realistic** Algorithm, and it implements a balance between error-driven (backpropagation) and associative (Hebbian) learning on top of a **biologically-based** point-neuron activation function with inhibitory competition dynamics (either via inhibitory interneurons or an approximation thereof), which produce k-Winners-Take-All (kWTA) sparse distributed representations.

a **biological** neural network is composed of 3 hierarchies: neuron -\> layer -\> network

Why is it not: neuron -\> network ?

suppose you have a brain with $10$ neurons, then the neural network can be described as a $10\times 10$ connectivity matrix, and that's all, right?

Why do you need, for example, to divide the $10$ neurons into $2$ layers, and each layer has $5$ neurons, and how do you even distinguish them? (how do you know which neuron belongs to which layer?)

# Answer
> 2 votes
This is not really a question related much to biological neural networks, rather it's a concept from artificial neural networks that are arranged in layered structure.

In a layered artificial neural network, "neurons" of one layer receive input *only* from the previous layer, and give output *only* to the subsequent layer. This creates a computationally efficient feed-forward structure: there's no complicated recurrence, once you know the activities of one layer you can calculate the activities of the next layer by a single multiplication step between the weight matrix and activity vector of the previous layer, followed by a sum for each unit.

From the README of the software you link to:

> There are 3 main levels of structure: Network, Layer and Prjn (projection). The network calls methods on its Layers, and Layers iterate over both Neuron data structures (which have only a minimal set of methods) and the Prjns, to implement the relevant computations. The Prjn fully manages everything about a projection of connectivity between two layers, including the full list of Syanpse elements in the connection. ... The Layer also has a set of Pool elements, one for each level at which inhibition is computed

So, while the neurons in this network may have some biological aspects like integration over time, it seems they are arranged into layers like a classical ANN, information is shared between layers through a "Prjn" object that manages the "synapses" between two layers. Additionally, each layer seems to have its own inhibitory unit. I assume the way this is modeled is that every neuron in a layer gives input to an inhibitory unit, which then reduces the activity within that layer as sort of a gain control. Again, while they may be biologically motivated, these are all artificial constructions for a computational model chosen by the authors.

While you could conceivably still map these connections all into an NxN matrix, everything would be zero except for upper triangular matrices corresponding to each pair of layers. Nothing about hierarchical organization says you can't put it in a larger matrix, just that it doesn't necessarily make sense to do so. For example, you could put students in a classroom into a longer list by school, that doesn't mean there isn't an underlying organization of students within classroom just because you abstracted out that level.

While there are also layered structures in biological networks (like neocortex) these layers do not function like artificial neural network layers, as neurons within layers are strongly connected to each other, and while there is some evidence for a "feed-forward" pathway (roughly, layer 4 to 2/3 to 5 to 6), this is only a moderate bias in connectivity and only a minority of connections actually follow this canonical pattern.

---
Tags: neural-network
---


# Question
Title: What are the reasons for human curiosity?
Accordingly to Maslow's pyramid, a good answer, in my opinion, in order to justify our behavior of "exploration/curiosity", could be in terms of the "physiological needs" step.

But, I think there are a lot more occurring in human psychology, for instance: "why a theoretical physicist works with subjects that don't have any sorts of immediate applications?". A fair answer would be: "because they are curious". So, we are 'curious" beings, we explore and embrace risks that are simply motivated by our curiosity.

I would like recommendations of literature and so on that discuss questions like "why do we explore?", "why we are attracted to the unknown?" and so on. So could you give me some references?

# Answer
> 1 votes
I think a valuable lead for you may be the search term ***novelty seeking*** (or, perhaps, the synonymous *neophilia*) which is closely related to *curiosity* (Collins *et al*., 2004);. Although traditionally linked to impulsivity, disorderliness and risky behavior (drugs, injuries), it is recognized that novelty seeking and satisfying curiosity are closely related phenomena. The following search terms in Google Scholar yielded a stack of \[seemingly\] interesting papers: "**scholarly + curiosity + novelty + seeking**", such as:

<sub>**References**
**-** Collins *et al*., *Personality and Individual Differences* (2004); **36**(5): 1127-41
**-** Kashdan *et al*., Oxford handbook of positive psychology (2009)
**-** Kidd & Hayden, *Neuron* (2015); **88**(3): 449-60
**-** Litman *et al*., *Personality and Individual Differences* (2005); **39**(6): 1123-33</sub>

---
Tags: reference-request, terminology, behavior
---


# Question
Title: What is an example of a type of talk therapy in which the therapist acts like a teacher and the patient is viewed as a student?
There are various types of talk-therapy.

For example dialectical behavioral therapy (DBT) is the name given to one particulair style of talk-therapy.

For the type of talk therapy my question is about we can assume that there is only one patient and one therapist in each therapy session. There are no group sessions with 3 or 4 people.

What is the name for a type of talk therapy in which the therapist is viewed as a teacher and the patient is viewed as a student? Alternatively, there is a mentor-mentee relatioship?

I think that the "teacher-student" I gave above is vague, so I will try to clarify:

If a patient does not learn a new way of thinking about somthing, then the patient will continue to think about that thing in the way that they are used to thinking about it.

For example, if an anorexic person does not learn a new way to think about food or a way to think about their body-image, then the anorexic patient will continue to refuse to eat food (or only eat small portions).

This extends to behaviors as well as thoughts.. If a patient does not learn about a new way to behave, then the patient will continue to behave in the way they used to behave.

For example, a patient might always cut people off in mid sentence untill a therapist teaches a patient how to become aware, and notice, when other people have finished their sentences.

That is, if a patient does not learn any new ways of thinking or new ways of behaving, then the patient's old thoughts and behaviors will perpetuate themselves.

Please assume that the patients wants to change their own patterns of thought or change their own behavior, but the patient not know how to do so.

For example, one patient might have smashed their own cellphone in a fit of rage more than three times in the last month. Such a patient might ask their therapist, "What can I do instead of smashing my cellphone when I am angry?"

Likewise, someone afraid to go outside (an agrophobe) might tell their therapist that they want go outside. The patient wants to learn how to overcome their own fear.

A lot of types of talk-therapy in use today (e.g. DBT) are very "hands off"

I met a man with a Ph.D in psychology who told me that it is "unethical" to provide advice to patients.

I am seeking the name for a style of talk-therapy where a therapist is allowed to advise their patients (only if the patient explicity asks for advice).

For example, a patient might lock and re-lock the deadbolt on their apartment door four times everytime they come home (e.g. Jack Nicolsen in a fictional portrayal; "As Good As it Gets" 1997). I have no wish for therapists to stop a patient from locking and re-locking their door unless they ask, "how do I stop locking and re-locking my door each day?".

In what type of talk-therapy does a therapist seek to teach their patient how to replace their patterns of thought or behavior with alternative thoughts or behaviors, when the patient says that is what they want to do.

In what type of therapy is the therapists primary goal to teach the patient about some new peice of information, as if the patient was a student?

The new information would be new to the patient, but not new to the therapist or new to the field of psychology at large.

We wish to provide a patient with a strategy for managing their mental health problem which is novel to the patient, but it could be a very old technique (not ground breaking research) and it's not novel to the therapist; only novel to the patient.

Practitioners of this special type of talk therapy would likely agree with the following statement: "if a patient refuses to eat any food, then the patient will continue to refuse to eat food untill the patient learns about a new way to think about food or their self-image"

What type of talk-therapy describes a teacher-student relationship in which advice is given when it is asked for. No un-solicited advice is provided, but the the therapist will seek to change thoughts and behaviors if a patient says that they want to change their thought or behaviors.

The therapist would aim.to provide a patient with ideas,, strategies, suggestions, potential courses of action, etc... which the patient had not previously considered.

"Here is what you could differently next time"

This therapy would not be an exercise in active listening, or only providing emotional support.

The goal of this style of talk-therapy therapy would be to teach the patient how to deal with thoughts, emotions, and/or behaviors unwanted by the patient. For example, how to stop locking and re-locking the deadbolt on a door four times each time one enters a house or apartment.

# Answer
I have often heard people say that they believe counselling involves the therapist being a teacher and the client is to be taught how to deal with their situation. This is a false premise for reasons I mentioned in my answer to Why are counsellors not supposed to give advice or lead the client? Is it possible for a counsellor not to be leading?.

You mentioned Dialectical Behavioural Therapy (DBT) and there is a similar *"therapy"* called Cognitive Behaviour Therapy (CBT). Now, I have my thoughts on CBT et al. and in the main, I see them more as band-aids which are stuck over a problem to cover up the root causes so they are no longer affecting the client's behaviour. CBT, DBT, Acceptance and Commitment Therapy (ACT), Metacognitive Therapy (MCT) and similar are not counselling therapies. They are **very brief** integrative models of approach (generally 6 sessions which are rigidly structured) **teaching** alternative ways of dealing with the effects rather than dealing with the root causes.

With CBT, for example, you might be presenting worry issues so they will help separate those worries into *"practical worries"* (problems that are affecting you right now) and *"hypothetical worries"* (worries not affecting you right now) and teach you to just put the *"hypothetical worries"* aside and just deal with the *"practical worries"*. For more on this see https://www.psychologytools.com/resource/worry-decision-tree/

In the CBT model, if there are no problems affecting you now, then great! You have nothing to worry about. But...

What if you are suffering from a degenerative physical medical condition? You may be worrying about how you may deal with life situations later when you are not able to walk as much. CBT says, don't worry about them because they are not affecting you right now. But, it may be beneficial to plan for those situations so that they are more easily managed when they do come up.

## Sorry, I digressed a little, but...

What I just said demonstrates why counselling is more open, takes longer, and does not directly teach you to do anything specific.

Psychotherapeutic counselling following an ethical framework will provide you a safe and non-judgemental space to discuss and explore the issues you are facing with a person who is trained to listen and guide you through your journey toward discovering how your issues manifested themselves and how you can deal with the root causes such as grief, loss, guilt, shame...

Feelings such as guilt and shame can be so ingrained that you need to spend time with a trained counsellor to properly "unpick it" and deal with it. What made you feel guilty? When did you start feeling that? Why?... Is your feeling of guilt justified in your opinion? Why? Based on your knowledge and ability **at the time**, could you **really** have done anything differently?...

Each person is different and so you cannot put the feelings neatly in one box and say "this is what you must do to deal with this".

Going through the questions such as those I gave examples of, you are given the opportunity to safely examine your thoughts and feelings to determine their validity and correct misconceptions built up of the the period of time you have been dealing with your root causes and current situations which have arisen.

How your counsellor helps will depend on the modality (type/model of approach) of therapy they employ. There are many modalities and generally speaking, they are grouped into:

If you find that your therapist is not right for you, there may be another therapist who is a better fit.

If you are in the UK, The Counselling Directory has a searchable database of registered counsellors, but any counsellor registered with a registering body accredited by the Professional Standards Association is qualified and experienced to provide private counselling.
> 2 votes

---
Tags: abnormal-psychology, therapy
---


# Question
Title: Why are there substances that give positive psychological effects but become unhealthy addictions?
In a very general way, why is the brain a system that responds euphorically in response to certain stimulants yet over time that substance may be addictive and have negative health effects?

What is it about the brain’s in-built mechanisms as well as evolution that did not cause the brain to respond positively to that which is good for health, aversively to that which is bad?

Why is there an initial positive incentive to use addictive drugs?

# Answer
**Short answer**
The brain with its reward centers did not evolve with purified plant-based stimulants (nicotine, cocaine) or synthetic variants ((meth)amphetamine and other designer drugs) around.

**Background**
Cocaine leaves have been chewed on for ages, but the trick is that the 'high' comes gradually and it is hardly addictive at all. The reward centers may be stimulated, but mildly. It wasn't until folks started to chemically isolate and purify the active ingredients in the leaves that the trouble began. These purified compounds flush the reward centers in the brain with dopamine, resulting in nearly instant longing for more (craving) when the high is over. After a while dependence to the drug can develop and consumption may become habitual. Note that tobacco is heavily processed to ensure a 'pleasant' taste and readily release of the addictive nicotine. The same can be said for the 'downers' (opiates and synthetic relatives like fentanyl).

Ethanol (stimulant and neuro-suppressant all in one) is another example; it occurs in nature in fermented fruit (you know the funny movies); yet fermented fruit with enough alcohol in it to become intoxicated wasn't available all-year round and the conditions have to be pretty perfect for it to happen in the first place. Only when people started to brew beer and purify ethanol to increase alcohol content through distillation the trouble (addiction and development of diseases associated with chronic alcohol abuse) started.

The reward centers in the brain (responsible for addiction) haven't evolved in the presence of all these purified and synthetic compounds. It evolved in eras where sugars, fat and salt were scarce. Now things are different, and people get addicted to drugs, get overweight because of the excess carbohydrates and fat they consume (also driven by the reward centers making them feel good) and develop kidney failure because of high salt intake.
> 5 votes

---
Tags: neuroscience, psychopharmacology, evolution, addiction
---


title: 10-BFI test score compiling

text:
# Question
Title: 10-BFI test score compiling
I am a physicist and I am doing a survey about musical genre preferences and correlation with a field of study.

I want to interpret the results from this test

I don't know how to interpret the legend, and whether there are some particular details to be taken into account:

Thank you to all.

Reference
https://doi.org/10.1016/j.jrp.2006.02.001

# Answer
On this website the scoring of the Big 5 is explained a bit better I think. They refer to the original Big 5 paper that you've linked.

From what I understand there are 10 questions, and each of the 5 character traits is represented by 2 questions. One question is counted as is, while the other question in the pair is reversed-scored to describe the character trait. The reverse scoring of one of the answer pairs is necessary because that question is asked in an opposite approach.

There are 5 traits (the Big 5):

**Extraversion**: 1R, 6
**Agreeableness**: 2, 7R
**Conscientiousness**: 3R, 8
**Neuroticism**: 4R, 9
**Openness to experience**: 5R; 10

So extraversion is scored using the reverse score of question 1 and the score of question 6. Note that the question 6 (asking to rate 'extravertness') is opposite to question 1 ('introvertness').

Likewise, agreeableness is scored using the score of question 2 and the reverse score of question 7. *etctera*.

Hope this helps.
> 2 votes

---
Tags: measurement, personality, methodology, experimental-psychology, big-five
---


title: Different kinds of reaction time

text:
# Question
Title: Different kinds of reaction time
During a physics experiment at school we needed to determine the velocity of a car by using a stopwatch to measure the time it took to cross a line. We were told to calculate the uncertainty of the measurement using the ~250ms average reaction time, but is this correct?

The GIF below shows a test I did by myself to see how accurately I could stop the stopwatch pointer at the 5 seconds white line/mark. On average I got an error of about ~20ms.

In this sense, there seems to be different kinds of reaction times: one where we are able to predict or expect what will happen, and another when we have to react suddenly and without warning, which would be the commonly told 250ms time.

Are there studies on this topic that differentiate between these twos reaction times? If there is indeed a difference, does the "predictive" reaction time change depending on the context? In the stopwatch case it is possible to get an accurate result because the pointer moves at a slow and constant speed, but in the case of a more erratic movement the reaction time could be probably longer.

# Answer
> 4 votes
I wouldn't call this "reaction time" but rather a form of accuracy: you're timing your press to the advance of the stop watch.

Reaction time is latency to respond to some stimulus, but in the situation you describe you aren't responding to the bar reaching the mark, the stimulus starts long before that in the motion of the stopwatch.

# Answer
> 2 votes
I reckon the 250ms referenced is reaction to an unknown/random effect.

I watch F1 and at every start they show the reaction time of the first two drivers as even 100ms faster reaction can be very important in determining who'd be #1 after the first corner.

It's usually in the .2 - .3 range for them

Try using this to gage your reaction time instead of trying to time a stopwatch: https://f1-start.glitch.me/

The same F1 driver that needs 253ms to register it randomly turning green (similarly to a race start) https://www.youtube.com/watch?v=rWtWC3FsY5M

Only needs 0.0069s to time it to exactly 6 seconds https://www.tiktok.com/@mclaren/video/6953908004311846150?is\_from\_webapp=v1&item\_id=6953908004311846150&lang=en

Meaning, as Bryan alludes that his reaction to the timer hitting 6s seems to have started at around 5.75s-5.8s

---
Tags: unconscious, reaction-time
---