Quantitative analysis of local neuronal systems in area 18 of the cat cerebral cortex

Summary form only given, as follows. The receptive fields of visually responsive cells recorded from area 18 of the cat visual cortex are not homogeneous. Close examination of the receptive fields indicates that they are formed by a discontinuous accumulation of subunits (active points). Subunit density is greatest in the region of the central excitatory core of the receptive field. In addition, most receptive fields contain a wide dispersion of many active points throughout their peripheral regions. The relationship between the number of central and peripheral active subunits is highly predictive and consistent. Although the receptive fields of neighboring visual cells overlap, the distribution of their respective active points appears to be complementary, thus suggesting that these cells may function as motion detectors in the visual system. Mass correlograms (histograms of interspike intervals) calculated from the multiple-unit activity record of interspike intervals support this conclusion. A consistent 3-ms rhythmic activity was observed in the mass correlograms when the receptive fields were stimulated along the axis of the optimal directional preference.<>