What happens to the congenitally blind’s visual cortex? this region does not simply stay dormant and gather cobwebs; rather, it appears this area puts up the scaffolding and undergoes a massive reconstruction, making office space for language use.
Cognitive and neuroscientific research has shown the brilliant flexibility of the traditional language and visual networks to restructure and adapt to focal lesions or sensory deprivation. Compared with visually functional individuals, blind people’s language processing seems to co-opt the brain regions traditionally associated with vision. In tasks where participants must attempt to generate verbs from a given noun, blind individuals showed comparably greater levels of occipital (“primary visual cortex”) activation. Stereotypically, in visually functional individuals, this form of task would entail the sole activation of areas, like the temporal lobes, that are traditionally associated with language processes. In blind individuals, however, it appears the burden of verbal knowledge gets shared between the traditionally language dominated brain areas and their sensory deprived visual cortices. Language, it seems, is greedy and will make use of every nanometre of grey and white matter available. But why should language be favoured, rather than, say, motor function or number representation in what cognitive function gets to have the unused visual space?
It could be something to do with expanding the functional verbal working memory capacities of blind individuals. The brain could be playing to its strengths, as it were, and capitalising on what’s already handy.
Studies have found that congenitally blind individuals outperform those with sight on verbal working memory tasks. The cognitive faculty of working memory is invoked as a response to tasks that require you to hold goal-relevant information actively in mind, whilst also having to simultaneously act upon other bits of incoming information. On average, the information we can hold in mind, whilst performing other tasks too, is minimal. So, any advantage the brain can achieve in this domain will be taken.
Amir Amedi, and his colleagues, found that the occipital lobes were significantly churning their cogs when presented with verbal-memory tasks in blind individuals. This brain region appeared to show specialisation for holding verbal meaning in mind and generating verbs when cued by a noun.
These findings emphasis the ability of the brain to organically adapt, change and to not leave anything to waste. If there is any bit of grey matter not in use and atrophying away, the brain wont hesitate to participate in some junk matter modelling – yielding greater functionality.