What are the functions of primary visual cortex (V1)?

TL;DR

Recent research reveals that primary visual cortex (V1) functions as a saccade guide, a processing bottleneck, and a facilitator of recognition, emphasizing its role in visual attention and information flow.

Contribution

This paper synthesizes new functions of V1, highlighting its roles in saccade guidance, information bottleneck, and top-down recognition support.

Findings

V1 acts as a motor cortex for saccades via a saliency map.

V1 creates a processing bottleneck reducing visual information.

V1 supports recognition through top-down feedback.

Abstract

Although Hubel and Wiesel established decades ago how individual V1 neurons transform retinal inputs, functions of V1 as a whole are being discovered only recently. First, V1 acts as a motor cortex for exogenously guiding saccades by constructing a bottom-up saliency map of the visual field. Second, V1 initiates a processing bottleneck: a massive reduction of visual information begins at its output to downstream areas. Third, downstream recognition is limited by impoverished information, V1 supports ongoing recognition by providing additional information queried by top-down feedback from downstream areas, directed predominantly to central visual field representations. These V1 functions underpin a framework in which vision is mainly looking and seeing through the bottleneck. Looking selects a fraction of visual information into the bottleneck, largely by saccades that center selected contents at gaze. Seeing recognizes the selected contents. Looking and seeing rely mainly on processing in the peripheral and central visual fields.