(uh oh) Is the brain really that plastic? Perhaps not

[HuckleB]

Is the brain really that plastic? Perhaps not

http://www.medicalnewstoday.com/medicalnews.php?newsid=24757

"The visual cortex of the adult primate brain displays less flexibility in response to retinal injury than previously thought, according to a new study published in the May 19, 2005, issue of the journal Nature. This may have implications for other regions of the brain, and the approach the investigators used may be a key to developing successful neurological interventions for stroke patients in the future.

Stelios M. Smirnakis, a Howard Hughes Medical Institute physician-postdoctoral fellow at Massachusetts General Hospital, and colleagues including Nikos K. Logothetis of the Max Planck Institute for Biological Cybernetics used functional magnetic resonance imaging (fMRI) to monitor cortical activity for seven and one-half months after injury to the retina of adult monkeys. They found limited reorganization in the primary visual cortex.

Their results contradict previous thinking. In a “News and Views” commentary published in the same issue of Nature, Martin I. Sereno, a neuroscientist at the University of California, San Diego, says the latest data indicate that adult brains may be less plastic than scientists had hoped.

In children, the brain's ability to compensate for injuries is well known. Children with severe epilepsy who lose an entire hemisphere during surgery can regain motor control on the affected side of their body and go on to develop normal language skills. But in adults, the case for brain plasticity has been less clear.

..."






It's but one study, so it must be taken in to context. Still, this could be the start of a sort of "correction" in thinking about brain plasticity. On and on it goes, a never-ending story, or so it seems. I love the brain!

[Just Me]

1. I feel confident that it's a good thing the brain remains a mystery.

Although, I confess I have difficulty in buying the "bottom line" assertion of this study that the human brain isn't plastic based upon studies of a retina-injured adult monkeys.

[HuckleB]

2. I guess science isn't LBN?

Only care crashes and tornadoes for that crowd.

:shrug:

[jasmeel]

3. Lack of long-term cortical reorganization after macaque retinal lesions

This is from the article-interesting stuff...

<snip> Our results contrast with 5 different studies indicating that substantial long-term reorganization occurs over 2−6 months and that the Lesion projection zone border shifts by about 5 mm (refs 1−4).

<snip>
Our results also contrast with a recent report by Baker et al. of extensive reorganization in human visual areas, including area V1 (ref. 35). Those measurements were made in two adult human subjects who had been diagnosed with macular degeneration covering the fovea nearly 20 years earlier. In contrast, Sunness and Yantis found no significant plasticity in a human subject with a partial macular lesion diagnosed 2 years before measurement36, and this has been confirmed in a second subject with a relatively complete macular lesion (B.A.W., J. Liu and S. Nagadomari, unpublished observations). These human measurements, coupled with the present macaque data, indicate that large-scale cortical reorganization in adult V1 might not occur until at least several years after sensory deprivation.<snip>