> On Mon, 10/26/09, Keith Henson <[email protected]> wrote:
> Most of you have probably seen this, but better an extra copy than
> none at all. Keith
>
> http://www.technologyreview.com/biomedicine/23695/
> ==================================================
<much snippage>
> ...With the advent of technologies such as magnetic resonance
> imaging (MRI), researchers concentrating mainly on gray matter have
> been able to map the parts of the brain that appear to play a role.
> But this has taken them only so far, and the focus on gray matter has
> not told the whole story. Not until the last few years, as new
> variations of MRI home in on the brain's white matter, has a deeper
> understanding begun to emerge. "Scientists are now able to switch the
> focus from particular regions of the brain to the connections between
> those regions," says Sherif Karama...
> ...The type of MRI typically used for medical scans does not show the
> finer details of the brain's white matter. But with a technique called
> diffusion tensor imaging (DTI), which uses the scanner's magnet to
> track the movement of water molecules in the brain, scientists have
> developed ways to map out neural wiring in detail. While water moves
> randomly within most brain tissue, it flows along the insulated neural
> fibers like current through a wire...
This is what Bob Zimmerman was working on; has anyone heard from him lately?
> ...It's likely that the quality of white matter is at least partly
> genetically determined and, therefore, difficult to change. The size
> of the corpus callosum, the thick tracts of white matter connecting
> the two hemispheres of the brain, is about 95 percent genetic. And
> about 85 percent of the white-matter variation in the parietal lobes,
> which are involved in logic and visual-spatial skills, can be
> attributed to genetics, according to Thompson. But only about 45
> percent of the variation in the temporal lobes, which play a central
> role in learning and memory, appears to be inherited...
> ...But environmental factors also play a role. Rodents raised in a
> stimulating environment have more white matter....Although the adult
> brain isn't as malleable as a young brain, and is
> therefore less easily influenced by environmental factors,
> evidence is growing that the adult brain is still remarkably plastic.
> Scientists haven't yet studied white matter enough to know how to
> improve it directly, especially in healthy people. But exercise, diet,
> and mental activity have all been shown to boost brain health and
> decrease the risk of dementia, a disorder that has been linked to
> white-matter damage. And other studies have shown that just a few months
> of practicing a new skill can enlarge certain parts of the brain...
Like when a sighted person is blind-folded for a week+, their auditory and
tactile areas increase (and IIRC, the "unused" portion of the brain devoted to
vision may alter as well?).
> ...Haier envisions a day when brain scans could alert
> teachers to the cognitive strengths and weaknesses of each
> student, so that lessons could be individually tailored. It might be
> possible to derive much the same information from extensive cognitive
> testing, but such testing is rare because it's expensive and time
> consuming. A 15-minute brain scan, on the other hand, might be applied
> much more broadly...
That's the good side-
Und now fur ze Dark Zide:
> ...Some experts, however, fear it will create the sense that
> people's abilities are completely predetermined...But because
> a brain scan measures a physical property, it's likely to
> arouse even more concern than today's testing methods. "If you can
> estimate someone's IQ from a brain scan, even if it isn't any more
> predictive than an SAT [score], it gives the illusion that his or her
> future is fixed," says Karama...
Shades of GATTAGA (IIRC that title)!
But so much potential to follow and fix broken nerve tracts - spinal cord
injuries repaired, brain trauma reversed - wow.
Debbi
Tracking The Bouncing Ball Maru
_______________________________________________
http://mccmedia.com/mailman/listinfo/brin-l_mccmedia.com
