Unique Spatial Integration in Mouse Primary Visual Cortex and Higher Visual Areas

Abstract

Neurons in the visual system integrate over a wide range of spatial scales. This diversity is thought to enable both local and global computations. To understand how spatial information is encoded across the mouse visual system, we use two-photon imaging to measure receptive fields (RFs) and size-tuning in primary visual cortex (V1) and three downstream higher visual areas (HVAs: LM (lateromedial), AL (anterolateral), and PM (posteromedial)) in mice of both sexes. Neurons in PM, compared with V1 or the other HVAs, have significantly larger RF sizes and less surround suppression, independent of stimulus eccentricity or contrast. To understand how this specialization of RFs arises in the HVAs, we measured the spatial properties of V1 inputs to each area. Spatial integration of V1 axons was remarkably similar across areas and significantly different from the tuning of neurons in their target HVAs. Thus, unlike other visual features studied in this system, specialization of spatial integration in PM cannot be explained by specific projections from V1 to the HVAs. Further, the differences in RF properties could not be explained by differences in convergence of V1 inputs to the HVAs. Instead, our data suggest that distinct inputs from other areas or connectivity within PM may support the area's unique ability to encode global features of the visual scene, whereas V1, LM, and AL may be more specialized for processing local features.

Object manifold geometry across the mouse cortical visual hierarchy

“…2a ). However, if changes in receptive field size alone result in an increase in object discriminability we would expect that area PM that has very large receptive fields (Murgas et al, 2020) would also have high object discriminability which was not the case in our data ( Fig. 2 ).…”

“…The larger receptive field sizes of areas PM and AM (Murgas et al, 2020;Wang and Burkhalter, 2007) might contribute to the improved translation invariance that we observed relative to the other parameters.…”

“…2b ). Another potential confound might be differences in receptive field sizes across areas (Murgas et al, 2020;Wang and Burkhalter, 2007) . An area with larger receptive fields might be better at representing objects simply because more neurons are responding to the object at any moment.…”

Distinct recruitment of feed-forward and recurrent pathways across higher-order areas of mouse visual cortex

“…Thus, visual perception involves the coordinated evolution of specialized components of a stimulus across many areas of the brain. While many studies of hierarchical transformation have largely been conducted in primates, recent studies have demonstrated similar functional specialization in areas of mouse cortex (Andermann et al, 2011; Glickfeld and Olsen, 2017; Marshel et al, 2011; Murgas et al, 2020; Sit and Goard, 2020).…”

“…Consequently, different areas can share similar circuit motifs but have divergent functional properties depending on the inputs they receive (Glickfeld et al, 2013; Han et al, 2018; Matsui and Ohki, 2013). However, this divergence alone is insufficient to account for all differences in stimulus selectivity across areas (Blot et al, 2020; Glickfeld and Olsen, 2017; Murgas et al, 2020). The organization of HVAs around V1 separates many of these areas by millimeters of cortical space.…”