system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How hallucinogens like LSD or Psilocybin work in the brain to cause the effect they do.

I have spent years reading how these chemicals work in the brain, yet I'm not a science guy so anything technical that actually gives the answer is completely lost on me. I'm hoping one of you can help me to understand what happens in my brain to cause the craziness I perceive.
gpt
Normally, looking at, say, a red toy car will go something like this in the brain, explained very simply:

1. Light enters eye.

2. Eye translates light into impulses (little electric shocks) that the brain can interpret.

3. Brain receives impulses and translates them into little chemical packages for the "thinking" parts of the brain to interpret.

4. "Thinking" part of the brain interprets chemicals into a mental picture of a red toy car.


Now, if you didn't listen to mommy and daddy's advice and decide to take LSD, the process will become something like this:

1. Light enters eye.

2. Eye translates light into impulses.

3. Brain receives impulses, translates them into little chemical packages

4. "Thinking" part of the brain tries to interpret chemicals -- but *whoah*, there are LSD molecules in the way! Not all the chemical packages are taken in and translated as a result of this, and the mental image becomes distorted; instead of a red toy car, you see a very strange-looking pink/orange toy car with little feathers and stars dancing around its edges, and for some strange reason, you can't just *see* the car, you can *taste* its colours. You didn't even know this was possible until now and you don't have a clue how it's possible, but you can definitely taste the colours of the toy car.


So in short, psychedelics temporarily alter the way that information is organized in the brain and block some signals that would normally have been let through, and as a result, your mental image of the world is distorted into the trippy colours, shapes, sounds and sensations that people experience while on psychedelics.

(Not entirely sure if all of this is correct, but it's the best I've got.)