The representation of colored objects in macaque color patches

Le Chang,Pinglei Bao,Doris Y Tsao

doi:10.1038/s41467-017-01912-7

Le Chang, Pinglei Bao + Show 1 more

Open Access

https://doi.org/10.1038/s41467-017-01912-7

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Abstract

An important question about color vision is how does the brain represent the color of an object? The recent discovery of “color patches” in macaque inferotemporal (IT) cortex, the part of the brain responsible for object recognition, makes this problem experimentally tractable. Here we recorded neurons in three color patches, middle color patch CLC (central lateral color patch), and two anterior color patches ALC (anterior lateral color patch) and AMC (anterior medial color patch), while presenting images of objects systematically varied in hue. We found that all three patches contain high concentrations of hue-selective cells, and that the three patches use distinct computational strategies to represent colored objects: while all three patches multiplex hue and shape information, shape-invariant hue information is much stronger in anterior color patches ALC/AMC than CLC. Furthermore, hue and object shape specifically for primate faces/bodies are over-represented in AMC, but not in the other two patches.

Highlights

An important question about color vision is how does the brain represent the color of an object? The recent discovery of “color patches” in macaque inferotemporal (IT) cortex, the part of the brain responsible for object recognition, makes this problem experimentally tractable
Stimulating ALC in monkey M2’s left hemisphere activated three additional patches. Two of these patches overlapped with anterior fundus color patch (AFC) and CLC identified by the color localizer (Fig. 1d), while one of these patches was located anterior to the stimulation site, on the ventral surface of the inferotemporal gyrus medial to the anterior middle temporal sulcus
Consistent with our analyses with similarity matrices, we found that shapeinvariant hue information was higher in anterior color patches than in CLC, while hue-invariant shape information showed the opposite trend (Fig. 6)

Summary

Introduction

An important question about color vision is how does the brain represent the color of an object? The recent discovery of “color patches” in macaque inferotemporal (IT) cortex, the part of the brain responsible for object recognition, makes this problem experimentally tractable. To clarify how the representation of object color is transformed in the visual system following the extraction of local hue information at both the single-cell and population level, we targeted fMRI-identified “color patches” in inferotemporal (IT) cortex[5] for electrophysiological recordings in three macaque monkeys. Previous studies of color processing in monkeys have mostly used artificial stimuli, such as white noise, sinusoidal gratings, or simple geometric shapes[5, 10,11,12], while previous studies of object representation in IT have mostly used grayscale images, ignoring color variations[13, 14] This is unsatisfying, given that colored objects are the only natural visual inputs. We explored the corepresentation of color and object identity by presenting images of objects systematically varied in color, while recording from color patches in IT

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