The organization of orientation selectivity throughout macaque visual cortex.
A double-label deoxyglucose technique was used to study orientation columns throughout visual cortex in awake behaving macaques. Four macaques were trained to fixate while contrastreversing, stationary gratings or one-dimensional noise of a single orientation or an orthogonal orientation were presented, during uptake of [14C]deoxyglucose ([14C]DG) or [3H]DG, respectively. The two orthogonal stimulus orientations produced DG-labeled columns that were maximally separated in the two isotope maps (inter-digitated) in four areas: V1, V2, V3 and VP. The topographic change from interdigitated to overlapping columns occurred abruptly rather than gradually, at corresponding cortical area borders (e.g. VP and V4v, respectively). In addition, the data suggest that orientation column topography systematically changes with retinotopic eccentricity. In V1, the orientation columns systematically avoided the cytochrome oxidase blobs in the parafoveal representation, but converged closer to the blobs in the foveal representation. A control experiment indicated that this was unlikely to reflect eccentricity-dependent differences in cortical spatial frequency sensitivity. A similar eccentricity-dependent change in the topography of orientation columns occurred in V2. In parafoveal but not foveal visual field representations of V2, the orientation columns were centered on the thick cytochrome oxidase stripes, extended into the adjacent interstripe region, but were virtually absent in the thin stripes.
Vanduffel
Wim
W
Laboratorium voor Neuro-and Psychofysiologie, Katholieke Universiteit Leuven, Faculteit Geneeskunde, Campus Gasthuisberg, Herestraat 49, B-3000, Belgium. vanduffel@med.kuleuven.ac.be
Tootell
Roger B H
RB
Schoups
Aniek A
AA
Orban
Guy A
GA
D000818:Animals; D001522:Behavior, Animal; D001931:Brain Mapping; D002250:Carbon Radioisotopes; D003847:Deoxyglucose / Q000493:pharmacokinetics; D005403:Fixation, Ocular / Q000502:physiology; D005584:Fovea Centralis / Q000502:physiology; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D011877:Radionuclide Imaging; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000166:cytology / Q000000981:diagnostic imaging / Q000502:physiology*
D002250:Carbon Radioisotopes; D003847:Deoxyglucose