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Abstract:
Abstract: Using fMRI, normally hearing individuals and
congenitally deaf individuals were compared as they monitored
alternations of static and moving dots for brief brightness
changes. The changes could occur either in the central visual field
or in the peripheral visual field. When participants monitored the
peripheral visual field, greater recruitment of the motion
selective area (MT) was observed in deaf than in hearing
individuals, whereas the two groups were comparable when attending
to the central visual field. This finding indicates an enhancement
of visual attention specific to peripheral visual space in deaf
individuals. To assess whether this modification was specific to MT
or reflected a more widespread change within the motion pathway,
structural equation modeling was used to compute the effective
connectivity in each group between V1, MT and PP. The effective
connectivity between MT and the parietal cortex was found to be
stronger in deaf than in hearing individuals during peripheral but
not central attention. Thus, enhanced peripheral attention in the
deaf may be mediated by alterations of the connectivity between MT
and the parietal cortex, one of the main centers for spatial
representation and attention.
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