Psychology Stuff: Blind Sight

blind sight

coolest. thing. EVER.

Background you need to know:

The optic nerve leaves the eye and enters the brain though a hole in the back of the eye socket. In the brain it diverges. Part of it goes to the LGN (lateral geniculate nucleus) of the thalamus, and into area 17 of the striate cortex (occipital lobe). The other part goes to the superior colliculi in the mid brain. It's also known as the optic tectum. Frogs have an optic tectum, but no occipital lobe of course, so they famously have "frog vision." They can see five different things: motion, borders, and three other things I can't remember (I'll fill in these parts where I forgot if I ever remember to bring my notebook to the computer lab).

Now that you know that:

If area 17 is damaged, but your eyes and optic nerve and brain stem are still in tact, you will tell me that you cannot see. However, if I throw something at you, you'll duck out of the way. When I ask you why you did that, you have no idea.

This is because your optic tectum is still functioning, so you have frog vision, but it's completely unconscious. You have no idea that you're seeing.

The same thing can happen with hearing. Hearing goes to the MGN and then to many places but mostly the auditory cortex. It also goes to the inferior colliculi in the brain stem.

People with a damaged auditory cortex will tell you they can't hear, but they still jump if you make a loud noise, and they have no idea why. They essentially have frog hearing. They can hear, but not consciously.

How fucking cool is that?!?!!?