Opponent visuospatial coding structures responses during memory recall and visual perception in medial parietal cortex.

The mechanisms linking perceptual and memory representations in the brain are not yet fully understood. In the early visual cortex, perception and memory are known to share similar neural representations, but how they interact beyond early visual cortex is less clear. Recent work identified that scene-perception and scene-memory areas on the lateral and ventral surfaces of the brain are linked via a shared but opponent visuospatial coding scheme, with spatially specific visual responses in the absence of traditionally defined retinotopic maps. This shared visuospatial coding may provide a framework for perceptual-memory interactions. Here, we test whether the pattern of visuospatial coding within category-selective memory areas of the medial parietal cortex structures responses during memory recall and visual perception. Using functional magnetic resonance imaging, we observe signatures of visuospatial coding in the form of population receptive fields (pRFs) with both positive and negative response profiles within medial parietal cortex. Crucially, the more dissimilar the timeseries of a pair of positive/negative pRFs within a region, the more dissimilar their responses during both memory recall and visual perception. These are tasks that place very different demands on these regions: internally oriented memory recall versus externally oriented visual perception. These data extend recent work to suggest that the interplay between pRFs with opponent visuospatial coding may play a vital role in integrating information across different representational spaces.