Coding of chromatic spatial contrast by macaque V1 neurons
Abstract
Color perception relies on comparisons between adjacent lights, but how the brain performs these comparisons is poorly understood. To elucidate the underlying neural mechanisms, we recorded spiking responses of individual V1 neurons in macaque monkeys to pairs of stimuli within the classical receptive field (RF). We estimated the spatial-chromatic RF of each neuron and then presented customized colored edges using a novel closed-loop technique. We found that many double-opponent (DO) cells, which have spatially and chromatically opponent RFs, responded to chromatic contrast as a weighted sum, akin to how other V1 cells responded to luminance contrast. Yet other neurons integrated chromatic signals non-linearly, confirming that linear signal integration is not an obligate property of V1 neurons. The functional similarity of cone-opponent DO cells and cone non-opponent simple cells suggests that these two groups may share a common underlying neural circuitry, promotes the construction of image-computable models for full-color image representation, and sheds new light on V1 complex cells.
Data availability
All data associated with this study are available at https://github.com/horwitzlab/Chromatic_spatial_contrast
Article and author information
Author details
Funding
National Eye Institute (EY018849)
- Gregory D Horwitz
Office of the Director (OD010425)
- Gregory D Horwitz
National Eye Institute (EY01730)
- Gregory D Horwitz
National Institute on Drug Abuse (DA033461)
- Abhishek De
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocol (#4167-01) of the University of Washington. All surgery was performed under sevoflurane anesthesia, and every effort was made to minimize suffering.
Copyright
© 2022, De & Horwitz
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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