Abstract
Congenital blindness can lead to functional and neurochemical alterations in the occipital cortex. However, how such changes are coordinated and modulated between brain regions remain unclear. The basal nucleus of Meynert (BNM) is a group of neurons located mainly in the basal forebrain, and is a major source of cholinergic innervation to the cerebral cortex including the occipital cortex. While changes in cholinergic, glutamatergic and GABAergic metabolisms in the brain have been suggested in the absence of visual experience (Fine & Park, Annu. Rev. Vis. Sci. 2018), no studies have yet examined whether the functional connectivity of BNM is altered in congenital blindness. Here, we recruited 7 congenitally blind (age = 55.43 ± 5.18 years old) and 13 age-matched sighted subjects and obtained their resting-state functional MRI data with eyes closed using a 3 Tesla MRI scanner. We conducted a seed-to-voxel analysis using BNM as a seed and all voxels within the brain as targets. Our results showed that the functional connectivity between BNM and clusters in the occipital cortex of the right hemisphere is enhanced in the congenitally blind subjects (PFDR=0.01). Other brain areas did not show alterations in the functional connectivity to the seed BNM region between blind and sighted subjects (PFDR>0.05). Taken together, the current study shows that the BNM develops stronger functional connectivity to the occipital cortex under the condition of congenital blindness. This finding suggests that the strengthened projections of BNM to the occipital cortex may, at least in part, play a role in the coordination of the occipital cortex of blind people. Future studies may reveal whether the projections of BNM to the occipital cortex drives neurochemical alterations in the occipital cortex of blind individuals.