Reconstruction of shape contours from V1 activity at high resolution

The role of primary visual cortex (V1) in encoding physical stimulus features is well known, while stimulus categorization is mainly attributed to higher visual areas. However, visual experience is not stripped down to invariant, categorical-only "labels." Rather, visual experiences are remarkably rich with details resulting in high-resolution perception of objects. If V1 is involved in this process, high-resolution readout of shape contours should be possible from V1 activity. To test this, we presented various shapes to awake, fixating monkeys while recording V1 population activity using voltage-sensitive dye imaging. A simplified bottom-up model was constructed based on known cortical properties and without an image prior. Contours were reconstructed from single trials, in sub-degree resolution by applying the inverse model to neuronal responses. These novel reconstruction results suggest V1 can be an important constituent in the detailed internal representation of visual experiences.