The study investigates extra-receptive field (extra-RF) contextual modulation in area V1 of awake, behaving macaque monkeys. Contextual modulation was examined using texture displays where the receptive field (RF) was consistently stimulated with the same texture, but the perceptual context of this texture varied based on the configuration of extra-RF texture elements. The researchers found robust contextual modulation when disparity, color, luminance, and orientation cues defined a textured figure centered on the RF of V1 neurons. The spatial extent of this modulation was approximately 8 to 10° diameter parafoveally. Contextual modulation correlated with both binocularly rivalrous texture displays and simple surface occlusion displays. The latency of contextual modulation was found to be 80-100 msec after stimulus onset, suggesting potential feedback from extraretinal areas. The study also explored the range of visual cues that evoke extra-RF modulation, including binocular disparity, color, luminance, and orientation, finding that these cues generally evoked similar levels of modulation. Additionally, the spatial extent of extra-RF modulation was measured, showing a monotonically falling spatial tuning function that reaches the level of the homogeneous texture background at ~10° diameter. Finally, the study examined the relationship between contextual modulation and binocular rivalry, finding that displays that generate a cyclopean percept of a homogeneously textured field evoked the same level of neural activity as a truly homogeneous texture field, even when the monocular images contained clearly defined figures.The study investigates extra-receptive field (extra-RF) contextual modulation in area V1 of awake, behaving macaque monkeys. Contextual modulation was examined using texture displays where the receptive field (RF) was consistently stimulated with the same texture, but the perceptual context of this texture varied based on the configuration of extra-RF texture elements. The researchers found robust contextual modulation when disparity, color, luminance, and orientation cues defined a textured figure centered on the RF of V1 neurons. The spatial extent of this modulation was approximately 8 to 10° diameter parafoveally. Contextual modulation correlated with both binocularly rivalrous texture displays and simple surface occlusion displays. The latency of contextual modulation was found to be 80-100 msec after stimulus onset, suggesting potential feedback from extraretinal areas. The study also explored the range of visual cues that evoke extra-RF modulation, including binocular disparity, color, luminance, and orientation, finding that these cues generally evoked similar levels of modulation. Additionally, the spatial extent of extra-RF modulation was measured, showing a monotonically falling spatial tuning function that reaches the level of the homogeneous texture background at ~10° diameter. Finally, the study examined the relationship between contextual modulation and binocular rivalry, finding that displays that generate a cyclopean percept of a homogeneously textured field evoked the same level of neural activity as a truly homogeneous texture field, even when the monocular images contained clearly defined figures.