J Neurophysiol (February 1, 2003). 10.1152/jn.00478.2002
Submitted on Submitted 1 July 2002; accepted in final form 3 October 2002

Functional Organization of the Cat Visual Cortex in Relation to the Representation of a Uniform Surface

 ¹Laboratory of Neural Control, National Institute for Physiological Sciences, Okazaki-shi, Aichi, 444-8585;  ²Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki, 444-8585; and  ³Laboratory for Visual Neurocomputing, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan

Tani, Toshiki, Isao Yokoi, Minami Ito, Shigeru Tanaka, and Hidehiko Komatsu. Functional Organization of the Cat Visual Cortex in Relation to the Representation of a Uniform Surface. J. Neurophysiol. 89: 1112-1125, 2003. Neuronal activity in the early visual cortex has been extensively studied from the standpoint of contour representation. On the other hand, representation of the interior of a surface surrounded by a contour is much less well understood. Several studies have identified neurons activated by a uniform surface covering their receptive fields, but their distribution within the cortex is not yet known. The aim of the present study was to obtain a better understanding of the distribution of such neurons in the visual cortex. Using optical imaging of intrinsic signals, we found that there are a group of surface-responsive regions located in area 18, along the area 17/18 border, that tend to overlap the singular points of the orientation-preference map. Extracellular recordings confirmed that neurons responsive to uniform plane stimuli are accumulated in these regions. Such neurons also existed outside the surface-responsive regions around the singular points. These results suggest that there exists a functional organization related to the representation of a uniform surface in the early visual cortex.