http://mindhacks.com/2004/12/10/hack-102-alter-input-with-expectations/ Neuroscience and psychology tricks to find out what's going on inside your brain. Fri, 01 Jun 2012 08:12:09 +0000 hourly 1 http://wordpress.com/ http://mindhacks.com/2004/12/10/hack-102-alter-input-with-expectations/#comment-8621 Wed, 15 Dec 2004 15:09:55 +0000 http://mindhacksblog.wordpress.com/2004/12/10/hack-102-alter-input-with-expectations/#comment-8621 A friend who read this post wrote to say to me
//start-quote
Just a quick correction on your latest post about feedback. You state:
“For example, pathways ascend from the eye to the visual cortex (via the lateral geniculate nucleus [Hack #13]), but they also descent from the visual cortex to the eye (again via the lateral geniculate nucleus)”
As far as I know, in mammals, there is no pathway from the visual cortex or LGN to the Retina. There is a pathway from the visual cortex to the LGN however.
//end-quote
This is probably correct – there is no direct feedback from visual cortex to the retina, but there is feedback from the rest of the brain down the optic nerve towards the retina (see http://webvision.med.utah.edu/fbloops.html, especially section 5 which deals with mammals). So maybe no feedback from visual cortex, but from hypothalamus and maybe other regions. Feedback connections seems generally ill-understood and less celebrated than feed-forward connections. One neuroscientist told me at a conference that to invoke feedback connections in your explanation of a phenomenon was “the last refuge of a scoundrel”

]]> http://mindhacks.com/2004/12/10/hack-102-alter-input-with-expectations/#comment-8620 Mon, 13 Dec 2004 16:27:01 +0000 http://mindhacksblog.wordpress.com/2004/12/10/hack-102-alter-input-with-expectations/#comment-8620 Robert Anton Wilson talks a lot about this phenomenon and its relationship to mysticism. The mechanism described above is the answer to the koan “Who is the master who makes the grass green?” Light reflected off a blade of grass enters our eyes, information is transferred to our brains which organize the information and produce for us an image, which is the green-ness of the grass. Our experience of the grass is not the grass alone, nor is it our nervous system alone, but a combination of the two. The word yoga comes from the same root as yolk and essentially means “to bind two things together”. Hence, our experience is the yoga of the objective world and our nervous system.

]]>