Perceptual Texture Dimensions Modulate Neuronal Response Dynamics in Visual Cortical Area V4

Texture is an important visual attribute for surface pattern discrimination and therefore object segmentation, but the neural bases of texture perception are largely unknown. Previously, we demonstrated that the responses of V4 neurons to naturalis-tic texture patches are sensitive to four key features of human texture perception: coarseness, directionality, regularity, and contrast. To begin to understand how distinct texture perception emerges from the dynamics of neuronal responses, in 2 macaque monkeys (1 male, 1 female), we investigated the relative contribution of the four texture attributes to V4 responses in terms of the strength and timing of response modulation. We found that the different feature dimensions are associated with different temporal dynamics. Specifically, the response modulation associated with directionality and regularity was sig-nificantly delayed relative to that associated with coarseness and contrast, suggesting that the latter are fundamentally simpler feature dimensions. The population of texture-selective neurons could be grouped into multiple clusters based on the combi-nation of feature dimensions encoded, and those subpopulations displayed distinct temporal dynamics characterized by the weighted combinations of multiple features. Finally, we applied a population decoding approach to demonstrate that texture category information can be obtained from short temporal windows across time. These results demonstrate that the represen-tation of different perceptually relevant texture features emerge over time in the responses of V4 neurons. The observed tem-poral organization provides a framework to interpret how the processing of surface features unfolds in early and midlevel cortical stages, and could ultimately inform the interpretation of perceptual texture dynamics.

Automated summary

Through studying macaque monkeys, we found that different texture attributes show different temporal dynamics in the responses of V4 neurons, with slower response modulation for directionality and regularity, and faster response modulation for coarseness and contrast. Texture-selective neuron populations can be classified into clusters based on combinations of feature dimensions, and these subpopulations exhibit distinct temporal dynamics associated with weighted combinations of multiple features.