Question: How does the brain read the information sent from the eyes?
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Cool! Thanks for the website Emma. Its really interesting how the brain works because I think it’s really complex.
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That is really cool Emma.
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And I found out when I was on holiday in Sydney I went to a show called The Blue Man Group, and they were talking about the eyes. They said that on the eyes there are rods and cones, where the rods help you see black and white colour and the cones are three different colours that make what you see in colour. It’s really confusing!
emeralddragon101
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Good question! Emma also knows a lot about this, so be sure to ask her for details.
As you may already know, light reflects off the ‘rods’ and ‘cones’ in your eye, those then send an electrical signal through the optic nerve to several specialized brain centres. It actually builds up a picture of what you’re seeing on a field of neurons .
(Brain areas involved: superior colliculus, thalamus)
Fun fact: There is also a tiny brain center right above where the nerves from both eyes cross over. It just sits there checking whether it’s light outside and adjusts your body accordingly. It’s your biological clock!
(brain areas involved: suprachiasmatic nucleus (SCN) )
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The part of the cortex, or outer surface of the brain that receives the information from the eyes is called the Occipital Cortex.
It is at the very back of the brain, so if you ever get hit in the back of the head, you can “see stars”, just like the cartoons!
Did you know that the image of the world that the retina (at the back of the eye) sees is actually upside down? This happens because of the lens of the eye.
And, different animals can see different parts of the light spectrum-honey bees can see ultra violet light!
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The brain’s role in vision is very important – what you actually ‘see’ doesn’t get processed by your eyes, but the brain processes the information your eyes send it, to make sense of the world.
You can see this for yourself (pun somewhat intended) by doing the following exercise with this visual illusion – https://www.michaelbach.de/ot/mot_adapt/index.html
This illusion shows a moving pattern – stare at the middle of this pattern. After a while an image will appear where the pattern was. What should happen is when you see this new image after having stared at the moving pattern, the image should appear to move in the *opposite* direction to the original moving image.
Now, once you’ve done that with both eyes open, stare at the first pattern with one eye closed, and when the second picture appears, close your first eye and look at it with your OTHER eye. You should see the same illusion that you saw before – the picture should be moving in the opposite direction….even though you looked at both images with different eyes!!
This shows you that it’s not our eyes which actually process information, but our brains, because you still see the illusion when you look at the moving pattern and second image with different eyes. Pretty cool!
So the information from your eyes gets sent to your ‘Visual Cortex’ at the back of the brain, and different areas there are responsible for processing different types of visual information – some of these are really simple properties such as whether an object is light or dark, and there are more complex areas which process moving objects or shapes, right up to a really specific area which only processes faces!!
Isn’t it interesting that everything we see is actually processed and constructed into a meaningful picture by our brain, and not our eyes at all?!
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Nice answers from my fellow contestants! Working in brain stimulation as I do, you can actually stimulate the “visual cortex” at the back of the brain with magnetic or electrical fields, and it creates flashes of light (or phosphenes) in the person’s vision. It can help us understand vision by working backwards (from the brain to the experience of vision). It’s also a good party trick.
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