@article {DuyckENEURO.0395-20.2020, author = {Marianne Duyck and Audrey L.Y. Chang and Tessa J. Gruen and Lawrence Y. Tello and Serena Eastman and Joshua Fuller-Deets and Bevil Conway}, title = {Color tuning of face-selective neurons in macaque inferior temporal cortex}, elocation-id = {ENEURO.0395-20.2020}, year = {2021}, doi = {10.1523/ENEURO.0395-20.2020}, publisher = {Society for Neuroscience}, abstract = {What role does color play in the neural representation of complex shapes? We approached the question by measuring color responses of face-selective neurons, using fMRI-guided microelectrode recording of the middle and anterior face patches of inferior temporal cortex (IT) in rhesus macaques. Face-selective cells responded weakly to pure color (equiluminant) photographs of faces. But many of the cells nonetheless showed a bias for warm colors when assessed using images that preserved the luminance contrast relationships of the original photographs. This bias was also found for non-face-selective neurons. Fourier analysis uncovered two components: the first harmonic, accounting for most of the tuning, was biased towards reddish colors, corresponding to the L\>M pole of the L-M cardinal axis. The second harmonic showed a bias for modulation between blue and yellow colors axis, corresponding to the S-cone axis. To test what role face-selective cells play in behavior, we related the information content of the neural population with the distribution of face colors. The analyses show that face-selective cells are not optimally tuned to discriminate face colors, but are consistent with the idea that face-selective cells contribute selectively to processing the green-red contrast of faces. The research supports the hypothesis that color-specific information related to the discrimination of objects, including faces, is handled by neural circuits that are independent of shape-selective cortex, as captured by the multi-stage parallel processing framework of IT (Lafer-Sousa and Conway, Nature Neuroscience, 2013).SignificanceDoes the brain encode face-specific color signals, such as those related to health and emotion, through color responses of face-selective neurons? This paper addresses this question by providing the first, to our knowledge, quantitative measurements of the color-tuning of face-selective cells. Face-selective cells are not very responsive to pure color (equiluminant) pictures of faces. But both face-selective and non-face-selective cells are biased for warm colors. Information analysis shows that face-selective cells are not optimally tuned to discriminate face colors but suggests that the cells may contribute to discriminating the reddish component of faces. Alternatively, face-cell color tuning may reflect a broader adaptation of IT for the detection of objects, which are, in general, characterized by warmer coloring compared to backgrounds.}, URL = {https://www.eneuro.org/content/early/2021/01/13/ENEURO.0395-20.2020}, eprint = {https://www.eneuro.org/content/early/2021/01/13/ENEURO.0395-20.2020.full.pdf}, journal = {eNeuro} }