THE RESPONSIVE CHARACTER TO MOVING RANDOM-LINESTIMULI OF CAT''S AMLS AREA NEURONS
猫前内侧上雪氏区视神经元对运动随机线条的反应

A widely accepted theory for visual motion processing in the cortex consists of two stages: the primary visual cortex tunes to the direction of motion of oriented components of a complex stimuli and the outputs are integrated at higher visual areas, in which neurons are sensitive to the moving direction of the whole pattern. Neurophysiological studies using plaid as the stimulus have shown that in the primary cortex and lateral suprasylvian area (LS) of the cat neurons are selective to the orientation of the component grating rather than to the true direction of the drifting plaid, therefore termed component-motion selectivity (CM) cells, while in a extrastriate cortical area, the MST of the monkey, neurons are tuned to the motion direction of the whole pattern, and termed pattern-motion selective (PM) cells. The present study, using a series of moving random-line patterns as the stimuli, showed that more than half neurons studied in AMLS area exhibited PM-like tunings. Moreover the percentage of PM-like tunings gradually decreased with the increment of the length of the component line segments of the stimulus pattern, accordingly the percentage of CM-like tunings increased. These results may imply that PM- or CM- selectivity is not a fixed property for certain cells, alternatively, the directional tuning of the neurons can vary with the orientation element in stimuli.