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The Amazing Adaptability of Brain's Vision Center

posted by martyb on Friday August 21 2015, @03:39AM   
from the do-you-see-what-I-hear? dept.

Phoenix666 writes:

By early childhood, the sight regions of a blind person's brain respond to sound, especially spoken language, a neuroscientist has found. Working with individuals who are blind offers cognitive researchers an opportunity to discover how nature and nurture, or a person's genes and their experience, sculpt brain function, the researcher says.
...
Bedny, an assistant professor in the Department of Psychological and Brain Sciences, studied 19 blind and 40 sighted children, ages 4 to 17, along with Massachusetts Institute of Technology cognitive scientists Hilary Richardson and Rebecca Saxe. All but one of the blind children were blind since birth.

They monitored the children's brain activity with functional magnetic resonance imaging while the children listened to stories, music or the sound of someone speaking an unfamiliar language. The blind children's vision portion of the brain, the left lateral occipital area, responded to spoken language, music and foreign speech -- but most strongly to stories they could understand. In sighted children and sighted children wearing blindfolds, that same area of the brain didn't respond.

The researchers concluded that blind children's 'visual' cortex is involved in understanding language.

The neuroplasticity this demonstrates bodes well for our future ability to accommodate and control cybernetic implants. Perhaps we can implant lab-grown mini-brains to supplement what our natural brains can't...

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Original Submission

• Alternative (Score: 0) by Anonymous Coward on Friday August 21 2015, @03:48PM

  by Anonymous Coward on Friday August 21 2015, @03:48PM (#225894)

  From TFA:

  Before modeling, data were realigned to correct for head motion, normalized to a standard adult template in Montreal Neurological Institute space, and smoothed with a 5 mm smoothing kernel. Data were normalized to an adult template. Although small anatomical differences exist in the shape and size of brain regions among adults and children of this age, these differences are small relative to the resolution of the MRI data
  [...]
  We calculated PSC for every time point after the onset of the trial for each condition [(raw signal during condition - raw signal during rest)/raw signal during rest] * 100
  [...]
  We next looked at activity in right lateral occipital cortex to ask whether lateral occipital responses to spoken language were hemisphere specific...These results suggest that lateral occipital responses to spoken language are not left lateralized in blind children.
  [...]
  Notably, the whole-brain analyses reveal that in the current sample of blind children, occipital responses to spoken language were bilateral and not left-lateralized.

  This normalizing to template presumably consists of stretching/shrinking the MRI images to fit on a template, the regions of interest would then correspond to whatever set of coordinates. They may not be comparing the same regions in blind and sighted children since the visual cortex is reported to be of different size in blind children:

  The bilateral visual cortices of the early blind were significantly thicker than those of the late blind and the sighted controls, but the latter two groups did not differ significantly. This suggests reduced “pruning” of synapses in the visual cortex, which may be due to a lack of visual experience during a critical developmental period.

  http://www.jneurosci.org/content/29/7/2205.full [jneurosci.org]

  Also, the normalizing to rest activity poses a problem. If the visual cortex of blind children was less active at rest than sighted, their percent signal change (PSC) scores would be affected. The same change in activity would correspond to a greater PSC. It is not clear to me which measure would be more physiologically relevant. What is the justification for normalizing like that?

  Finally, why does the Science Daily article talk about the left lateral occipital area when in the paper they say the effect was bilateral? Interestingly they only report data for the left hemisphere in the paper though.