Spatial configuration of contextual stimuli influences inter-laminar interactions in macaque primary visual cortex

Our visual experience is a result of the concerted activity of neuronal ensembles in the sensory hierarchy. Yet how the spatial organization of objects influences neural activity in this hierarchy remains poorly understood. We investigate how the inter-laminar interactions in the primary visual cortex (V1) are affected by visual stimuli in isolation or with flanking stimuli at various spatial configurations that are known to exert a “crowding” effect on perception. Visual crowding is thought to be the primary limitation on object perception in peripheral vision, and the psychophysically identified “crowding zone” of impaired object identification is highly non-uniform. By employing dimensionality reduction approaches to simultaneous layer-specific population recordings, we determined the extent to which trial-to-trial fluctuations of population responses in the superficial layers of V1 are related to those in the input layer. We demonstrate that specific spatial configurations of contextual stimuli differentially modulate inter-laminar interactions by changing their fidelity and the balance between feedforward and feedback signaling, but not their structure. Remarkably, the modulations mirror the spatially non-uniform aspects of perceptual crowding. Our results suggest a model in which perceptual impairment under crowding is mediated by visual context integration in the superficial layers of V1 and posit that the non-uniformity in contextual inputs is the neural substrate of perceptual experience.