Highly Selective Receptive Fields in Mouse Visual Cortex

TLDR

Genetic tools in mice are powerful for dissecting cortical circuits, yet the visual cortex has been largely neglected because of its poor spatial acuity and lack of columnar organization such as orientation maps. The study aims to provide a quantitative description of receptive field properties in mouse V1 to enable its use for addressing longstanding questions in visual neuroscience. The authors recorded extracellular activity with silicon electrode arrays in anesthetized mice, using current source density analysis to locate layers and spike waveforms to distinguish putative excitatory and inhibitory units. Neurons in mouse V1 exhibit orientation and spatial‑frequency selectivity comparable to other species, display both linear and nonlinear spatial summation and contrast‑invariant tuning that vary with laminar position and cell type, and inhibitory neurons are generally less selective and more nonlinear.

Abstract

Genetic methods available in mice are likely to be powerful tools in dissecting cortical circuits. However, the visual cortex, in which sensory coding has been most thoroughly studied in other species, has essentially been neglected in mice perhaps because of their poor spatial acuity and the lack of columnar organization such as orientation maps. We have now applied quantitative methods to characterize visual receptive fields in mouse primary visual cortex V1 by making extracellular recordings with silicon electrode arrays in anesthetized mice. We used current source density analysis to determine laminar location and spike waveforms to discriminate putative excitatory and inhibitory units. We find that, although the spatial scale of mouse receptive fields is up to one or two orders of magnitude larger, neurons show selectivity for stimulus parameters such as orientation and spatial frequency that is near to that found in other species. Furthermore, typical response properties such as linear versus nonlinear spatial summation (i.e., simple and complex cells) and contrast-invariant tuning are also present in mouse V1 and correlate with laminar position and cell type. Interestingly, we find that putative inhibitory neurons generally have less selective, and nonlinear, responses. This quantitative description of receptive field properties should facilitate the use of mouse visual cortex as a system to address longstanding questions of visual neuroscience and cortical processing.