[Squirrel visual cortex neurons selective for contour orientation]

The receptive field organization of orientation-selective neurons was studied in the squirrel visual cortex. Neurons with mutual inhibiting on- and off-areas of the receptive field, partially and completely overlapping excitatory and inhibitory mechanisms were observed. Neurons of the second group are the most typical. They reveal orientation selectivity if the stimuli are in the excitatory area of the receptive field, the inhibitory areas outside the excitatory area sharpen the selectivity. It is supposed that no obvious differentiation between simple and complex neurons exist in the squirrel visual cortex.