Spatial mapping of activity changes across sensory areas following visual deprivation in adults

Loss of a sensory modality triggers global adaptation across brain areas, allowing the remaining senses to guide behavior more effectively. There are specific synaptic and circuit plasticity observed across many sensory areas, which suggests potential widespread changes in activity. Here we used a cFosTRAP2 mouse line to drive tdTomato (tdT) expression in active cells to spatially map the extent of activity changes in various sensory areas in adult mice of both sexes following two modes of visual deprivation. We found that in the primary visual cortex (V1) both dark exposure (DE) and enucleation (EN) caused an initial loss of active cells followed by a partial rebound, which occurred relatively more in the superficial layers. A similar pattern was observed in the secondary visual cortex, especially in the lateral areas (V2L). The spared primary sensory cortices adapted distinctly. In the primary somatosensory barrel cortex (S1BF) there was a change in the density of active cells dependent on the duration and the mode of visual deprivation. In the primary auditory cortex (A1), there was a relative reduction in the density of active cells in the superficial layers without a significant change in the overall density. There were minimal changes in the active cell density in the secondary cortices of the spared senses and the multisensory retrosplenial cortex (RSP). Our results are consistent with cross-modal recruitment of the deprived visual cortex and compensatory plasticity in the spared primary sensory cortices that can support enhanced processing and refinement of the spared senses. Significance Statement The neural basis for improved processing of the spared senses after losing vision is largely dependent on plasticity mechanisms driven by neural activity. Using a transgenic mouse model to label active neurons in a temporally controlled manner, this study reveals the spatial pattern of widespread activity changes across brain areas following visual deprivation in adult mice. The findings suggest that the deprived visual cortex undergoes an initial reduction in activity followed by a rebound suggestive of cross-modal recruitment. Activity changes in the spared primary sensory cortices conform to compensatory plasticity, which could support improved processing of the spared senses. The results highlight the presence of large-scale plasticity in the adult brain to compensate for loss of vision.