Don't Try This At Home Either: Perceptual Enhancement Among the Deaf

If febrile convulsions can confer benefits to learning and memory, then might other neurological disorders offer similar cognitive enhancement? As it turns out, an article in the newest issue of the Journal of Cognitive Neuroscience speaks to this very question, and turns up some fascinating results.

Authors Stevens and Neville first consider whether there might be some brain regions that are more plastic than others. If so, they ask, wouldn't these regions be the most likely to be disrupted by some developmental disorders, and yet also more likely to be enhanced in an attempt to compensate for yet other deficits?

As the authors discovered, this very pattern had been observed in the magnocellular visual pathway, an input to the brain's "dorsal stream" that is largely responsible for motion processing and the perception of low spatial frequencies. Stevens & Neville found a number of studies reporting motion processing deficits in dyslexics, autistics, and those with Turner or Williams syndrome, and yet they also found a completely separate literature describing enhanced motion processing in congenitally deaf populations.

Unfortunately, the techniques used to assess cognition in deaf and developmentally disordered individuals are often very different; given these differences, it was impossible to use previous literature make a definitive claim about the plasticity of the magnocellular pathway, and its "double-edged" nature - in which an overly plastic area can be either selectively enhanced or deteriorated, according to circumstance.

So, in the first demonstration of both neurocognitive enhancement and deficit within the same paradigm, the authors tested motion and central field visual processing in 17 deaf adults, 15 dyslexic adults, and sex-, age-, handedness-, education-, video-game-use-, and socioeconomically-matched control subjects. The results showed that dyslexics could detect motion only in a much smaller field-of-view than the control group. In contrast, the deaf group could detect motion across a much larger field of view than control subjects. No group differences were found in the central field visual processing task, which is primarily sensitive to parvocellular (as opposed to magnocellular) function.

Stevens & Neville concluded that "motion processing is selectively modifiable," and that neurplasticity thus has a double-edge: highly plastic brain regions, such as the magnocellular pathway, are both more vulnerable to deterioration, and yet more promising for enhancement, than other brain regions.


Blogger Argrow Images said...

Hello Chris

Could I ask you about drugs for
brain like Xanax, Prazepam and Serlain? What you think about them,
and is there better tritment for
depression and anxiety then all thes xanaxes? Thanks.

8/09/2006 10:50:00 AM  
Blogger Chris Chatham said...

Hi - I really don't know anything about those drugs, and so I can't really give any good advice!

Unfortunately, I also haven't found many blogs that focus on the intersection of neurobiology and psychiatry, so I'm not sure where to direct you. Sorry!

8/09/2006 10:53:00 AM  
Blogger Amanda said...

Your blog is very educational on many levels. I enjoyed reading your posts

8/09/2006 11:23:00 AM  
Blogger Candy Minx said...

So interesting...and what heavy topics here at your blog. I found this one post especially pertinent to me because I have dyslexia...and my mother is deaf in only one e ar but she is compromised. Um, which reminds me of something else, she always had a phobia of birds and about 6 years ago someone in Natural history mag published study of innner ear and hearing loss and phobias...

i dunno, just responding here off the top of my head, but what a blog and profession...you really have your work cut out for you.

nice to "meet" you,

8/09/2006 11:51:00 AM  
Blogger Rick Wezenaar said...

really interesting site!

good images too :) ( gotta say that, I'm photographer after all ;) )

will stay alert on new articles...


8/09/2006 03:55:00 PM  
Blogger Chris Tregenza said...

Fascinating stuff Chris.

The limited field of vision in dyslexia is interesting. One of the treatments I've tried is Light Therapy. As a treatment its hard to take seriously and many people would consider it quackary. However I tried it found it improved my field of vision. Here is my write up of using Light Thereapy


8/10/2006 02:14:00 AM  
Anonymous Anonymous said...

Hello Chris,
I thought you might be able to help me.
In spring I will take exams which include quick thinking tasks from maths. So is there any way of how to improve these skills or I have got nothing to do with them, because they are just imborn? Do the genes in this field take a big part or nothing i should worry about if i study properly?

8/10/2006 03:04:00 AM  
Blogger Heidi on Vashon said...

I would be curious to see what books you recommend for laymen (women) who want to scratch the surface of your topic. I am blackout blind in my left eye (incorrectable) and have always thought I had a sixth sense because of this handicap. I'm also a lefty, and wonder if it's related to only seeing in my right eye...as in right brain. Dunno.

This is a totally new topic to explore. Thanks.

8/10/2006 04:52:00 PM  
Blogger Chris Chatham said...

Hi remigus - You're probably best off just getting a review book!

Heidi - One book I really liked was "Phantoms in the Brain" by VS Ramachandran. It is written for laypeople but is very interesting nonetheless.

However, I don't know of any layperson books that focus exclusively on this idea of "pathology & plasticity."

8/11/2006 07:50:00 AM  

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