Short-term monocular deprivation in adult humans alters pulvino-cortical functional connectivity measured with resting-state fMRI at ultra-high field

In adult humans, a brief period (2 hours) of monocular deprivation induces a form of homeostatic plasticity. Stimuli in the deprived eye are transiently boosted, shifting perceptual ocular dominance towards the deprived eye and modulating visually evoked fMRI responses. Here we demonstrate that monocular deprivation also produces a functional reorganization of visual processing circuits as revealed by changes in functional connectivity. Ultra-high field 7T fMRI EPI resting-state sequences (with two TRs, 3000 and 1000 ms) were acquired in 20 normally sighted adult participants, before and after the application of a translucent patch on the dominant eye for two hours. During the acquisitions, participants kept their eyes closed. Functional connectivity was measured by correlating BOLD signals in each cortical voxel with those in a subcortical “seed” area: ventral (visual) pulvinar and LGN. The correlation was computed after performing temporal filtering (bandpass 0.01 - 0.1 Hz) and nuisance regression (fMRI time-course in a mask covering white matter and CSF voxels). Comparing functional connectivity before and after monocular deprivation, we found decreased connectivity of early visual areas (V1-V3) with the ventral pulvinar, but unchanged connectivity with LGN. These results suggest that the ventral pulvinar plays an important role in broadcasting signals that modulate sensory processing and that may implement the homeostatic plasticity of neural function.