Extensive topographic remapping and functional sharpening in the adult rat visual pathway upon first visual experience

Abstract

Understanding the dynamics of stability/plasticity balances during adulthood and how they are sculpted by sensory experience is pivotal for learning, disease, and recovery from injury. Although invasive recordings suggest that sensory experience promotes single-cell and population-level plasticity in adults, the brain-wide topography of sensory remapping remains unknown. Here, we investigated topographic remapping in the adult rodent visual pathway using functional MRI (fMRI) coupled with a first-of-its-kind setup for delivering patterned visual stimuli in the scanner. Using this novel setup, and coupled with biologically-inspired computational models, we were able to noninvasively map brain-wide properties (receptive fields (RFs) and spatial frequency (SF) tuning curves) that were insofar only available from invasive electrophysiology or optical imaging. We then tracked the RF dynamics in the chronic Visual Deprivation Model (VDM), and found that light exposure progressively promoted a large-scale topographic remapping in adults. Upon light exposure, the initially unspecialized visual pathway progressively evidenced sharpened RFs (smaller and more spatially selective) and enhanced bandpass filters in SF tuning curves. Our findings reveal that visual experience following VDM reshapes the structure and function of the visual system and shifts the stability/plasticity balance in adults.