title: Hue Selectivity in Human Visual Cortex Revealed by Functional Magnetic Resonance Imaging.
abstract: The variability of color-selective neurons in human visual cortex is considered more diverse than cone-opponent mechanisms. We addressed this issue by deriving histograms of hue-selective voxels measured using fMRI with a novel stimulation paradigm, where the stimulus hue changed continuously. Despite the large between-subject difference in hue-selective histograms, individual voxels exhibited selectivity for intermediate hues, such as purple, cyan, and orange, in addition to those along cone-opponent axes. In order to rule the possibility out that the selectivity for intermediate hues emerged through spatial summation of activities of neurons selectively responding to cone-opponent signals, we further tested hue-selective adaptations in intermediate directions of cone-opponent axes, by measuring responses to 4 diagonal hues during concurrent adaptation to 1 of the 4 hues. The selective and unidirectional reduction in response to the adapted hue lends supports to our argument that cortical neurons respond selectively to intermediate hues.
authors.affiliation: Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kuriki
authors.affiliation: RIKEN Brain Science Institute, Wako-shi, Japan Current Address: Department of Psychology, Tsinghua University, Beijing, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Sun
authors.affiliation: RIKEN Brain Science Institute, Wako-shi, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ueno
authors.affiliation: RIKEN Brain Science Institute, Wako-shi, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: RIKEN Brain Science Institute, Wako-shi, Japan.
authors.forename: Kang
authors.initials: K
authors.lastname: Cheng
mesh_terms: D000222:Adaptation, Physiological; D001931:Brain Mapping; D003116:Color; D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity; D006801:Humans; D008279:Magnetic Resonance Imaging; D010775:Photic Stimulation; D011601:Psychophysics; D014793:Visual Cortex / Q000502:physiology*
keywords: color vision; fMRI adaptation; functional MRI; hue selectivity; human visual cortex; population histogram