Cortical visual plasticity in navigation – VIPLANAV

To control the movement and position of our body during spatial navigation, our brain must accomplish formidable tasks. Vision strongly influences the neuronal representation of space and this integration is crucial for survival and the emergence of spatial memory. Visual information reaches the primary cortical visual area (V1) and it is then transferred to higher-order visual areas, such as V2M, where it is integrated with other sensory modalities, and motor signals. Cortical networks are orchestrated by many inhibitory neurons. Among them, parvalbumin (PV)-expressing cells synchronize cortical networks during cognitive behaviors and shape the critical period of plasticity. In V1, accumulation of perineuronal nets (PNNs) around PV cells is responsible for limiting plasticity in the adult visual cortex. Our pilot data show that PNN enrichment around PV cells is absent in V2M, and this correlates with lower expression of PV itself. This indicates that adult V2M is more plastic than V1. Here we hypothesize that (1) the differential enrichment of PNNs around PV cells in V1 and V2M confers different physiological properties to neuronal circuits in the two visual cortical areas; (2) the reduced density of PNNs in V2M enables a higher degree of plasticity for establishing higher-order visual computations; (3) such a higher-order computation includes learning discrepancies between self-generated and external visual motion. The research proposed here addresses fundamental neurobiological questions, such as: how does the visual system use non-sensory information to adjust visual perception during specific brain states? How is vision used for navigation and spatial memory? Our work will provide a fundamental understanding into how the brain uses visual signals to navigate the world.