how is the brain able to give us images when we are imagining something?
In: Biology
So someone asked this same question about 5 years back. There was a pretty good explanation there from u/michaelhyphenpaul that I’m going to paste below. Something to note would be that 5 years is quite a long time for a field like neuroscience where we’re learning more almost every day, but nothing about their answer seems off to me. Anyways, here it is!
>Going for an explanation a 5 year old might really get:
Part of your brain (the back part) controls vision. When you see a real banana, that part of your brain responds to the light coming into your eyes, and it tells the rest of your brain about what the banana looks like. It says things like “it’s yellow,” “it’s curved,” and “it has a brown spot right in the middle.”
>When you imagine something, the visual part of your brain isn’t responding to the light coming into your eyes. Instead, it’s responding to what you’re thinking about. You remember what a banana looks like, so you can imagine it. The same kind of messages are being sent by the visual part of the brain to other parts (yellow, curved, brown spot). But when you’re imagining, the messages are less clear then when you really SEE a banana. That’s why “it’s there, but it isn’t there.”
>But, this is really a good thing. Think about this: what would happen if you COULD really see something when you imagined it? Every time you imagined a tiger, you’d see a tiger appear in the room! That would be bad; you’d probably run around screaming and being scared a lot. So your brain has evolved a way to let you imagine things without being confused whether or not you’re really seeing them.
>OK, bonus ELI-25 time: There’s a really cool study that came out recently, which looked at exactly this question. They used functional MRI to examine how responses in the visual cortex differ when people saw a set of 5 familiar paintings, versus when they imagined them. They found similar (but for the sake of simplicity, messier) response patterns during imagery versus perception, even in the lowest levels of visual cortex, suggesting that imagining a picture activates these parts of the brain in a similar way to actually seeing it.
>Here’s a link to the paper: http://www.sciencedirect.com/science/article/pii/S1053811914008428
>In the interest of full disclosure, I’m friends and colleagues with some of the authors, and I was around when they were working on this project (was finishing my PhD in neuroscience at the time), though I wasn’t directly involved in their work.
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