title: Slab-like functional architecture of higher order cortical area 21a showing oblique effect of orientation preference in the cat.
abstract: Optical imaging based on intrinsic signals is a powerful tool for in vivo studying functional organization of various cortices. Here, the functional architecture of orientation-sensitive neurons in higher order extrastriate cortical area 21a was investigated in cats using optical imaging combined with electrophysiological methods. It is found that neurons in area 21 with similar preferred orientations were functionally organized into a slab-like columnar structure orthogonal to the cortical surface, and the orientation columns were distributed more densely than those in area 17. The responsiveness and activated areas of optical maps visually elicited by the horizontal and vertical gratings were always larger than those by oblique gratings in areas 21a and 17. This neural oblique effect shown in orientation maps was more significant in area 21a than that in area 17. The findings suggest a neuronal mechanism in the higher order extrastriate cortex involving the visual perceptive process of the superiority of cardinal contours.
authors.affiliation: Vision Research Lab, Center for Brain Science Research, School of Life Sciences, Fudan University, Shanghai 200433, PR China.
authors.forename: Luoxiu
authors.initials: L
authors.lastname: Huang
authors.forename: Tiande
authors.initials: T
authors.lastname: Shou
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Hongbo
authors.initials: H
authors.lastname: Yu
authors.forename: Chao
authors.initials: C
authors.lastname: Sun
authors.forename: Zhiyin
authors.initials: Z
authors.lastname: Liang
mesh_terms: D000818:Animals; D001931:Brain Mapping; D002415:Cats; D003627:Data Interpretation, Statistical; D003952:Diagnostic Imaging; D004594:Electrophysiology; D009475:Neurons, Afferent / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology