Naked Science Forum

On the Lighter Side => New Theories => Topic started by: Anin on 19/04/2015 12:13:17

Title: Is there evidence of optical processing in human beings?
Post by: Anin on 19/04/2015 12:13:17

I am trying to understand why there is a strong visual resemblance between:
 
(1)   a common geometric hallucination (a phosphene)
(2)   a flickering wheel illusion caused by microsaccades (which in turn are linked to neural oscillations).
(3)   a spiral phase mask.

See link for images  https://prezi.com/v1o1u0kvwwu8/what-do-we-know-about-the-visual-system/

Could it indicate multiple oscillations and period forcing are resulting a devils staircase and a devils vortex lens.

Can anyone help me with any other explanations for the resemblance.   

Title: Re: Is there evidence of optical processing in human beings?
Post by: Colin2B on 19/04/2015 23:06:22

Quote from: Anin on 19/04/2015 12:13:17

Can anyone help me with any other explanations for the resemblance.

Unfortunately your images aren't showing up on ipad, so will have to look on PC to see if that works.
The tendency of the eye to seek out edges plus the brain's natural pattern seeking, seem to be responsible for many illusions of this type. Certainly optical and auditory illusions give us interesting insights into how our perceptions can be wrong and how the brain has an amazing ability to try and fill in the gaps.
Where do you think the processing might take place?

Title: Re: Is there evidence of optical processing in human beings?
Post by: chiralSPO on 19/04/2015 23:24:21

I'm not exactly sure what you mean by "processing"

My understanding is that there is a lot of encoding/compression that occurs in the retina (http://en.wikipedia.org/wiki/Retina), before signals are sent through the optic nerve. Then the occipital lobe (http://en.wikipedia.org/wiki/Occipital_lobe) does even more with the information. A friend of mine was in a car accident several years ago, and the back of his head was injured in such a way that the imagery from his left eye appeared to be rotated 90°! Luckily it adjusted back to almost normal over the course of many months...

Then there is interpretation and association that involves many other parts of the brain.

Title: Re: Is there evidence of optical processing in human beings?
Post by: Colin2B on 19/04/2015 23:55:26

Quote from: chiralSPO on 19/04/2015 23:24:21

My understanding is that there is a lot of encoding/compression that occurs in the retina

Interesting description of how edge detection is performed in the retina, most people would guess it to be an occipital lobe function.
Also interested to see mention of Na+ channels as I'm reading a book by one of the researchers on ion channels, fascinating!