Research Information System
Society For Neuroscience, Illinois, United States Of America, 5 - 09 October 2024, pp.712-713, (Full Text)
When sensory brain regions are deprived of their typical inputs, they activate
differently compared to non-deprived sensory regions. In blind individuals, visual regions
activate during a wide range of auditory, tactile, olfactory, and language tasks, whereas in deaf
individuals, auditory regions activate during visual and tactile tasks. The exact functions that
deprived sensory regions might have taken, however, remain unclear. This issue is of immense
interest because of its implications for understanding the brain’s areal specialization and the
extent to which the brain can change with experience. Prior reports have indicated that deprived
sensory cortices, especially visual cortices in congenitally blind individuals, show activation
during tasks requiring higher-cognitive functions such as working memory, response inhibition,
episodic memory recall, and mathematical operations. This suggests that these deprived sensory
regions might have integrated into the multiple-demand (MD) network. MD regions, a group of
fronto-parietal areas, respond to any cognitive control demands across different sensory
modalities.Our study examined whether deprived sensory cortices show the key characteristics
of MD regions, that is, activation of the same foci in response to diverse control demands. We
had 22 congenitally and early blind, 20 sighted control participants, and 10 early deaf
participants performed up to four diverse fMRI tasks involving different modalities. Each of the
four tasks contained an alternating sequence of easy and hard blocks. In the hard blocks of these
four tasks, participants (1) made more difficult tactile size-judgments, (2) maintained and
updated more working memory items, (3) made more demanding time-duration judgments, and
(4) executed speeded motor responses. We also performed task-based functional connectivity on
the collected data. Our findings showed that, in addition to fronto-parietal MD regions, almost
the entire occipital cortex in the blind group activated in response to the diverse control demands
and was functionally connected with MD regions. The occipital cortex in the sighted group did
not show such activation. Crucially, we found that the same set of individual occipital voxels,
delineated on each blind subject’s unnormalized and unsmoothed images, that are most sensitive
to one type of control demand (e.g., tactile decision-making task) also responded robustly to the
remaining three types of control demands (e.g., working memory updating, sensory-motor speed,
and time-duration judgment tasks) (BF > 28). Auditory regions in the deaf group, however, did
not show such control-related activation.