Fig. 1

Orientation and direction selectivity in visual cortex. a Left: A bar visual stimulus that is swept back and forth across the receptive field of a cortical neuron. The orientation of the bar is varied over 4 angles, and the direction of motion of the bar is varied over 8 directions. Right: Responses to stimulation at different orientations and directions. This particular neuron responds to many orientations and directions, but provides particularly strong responses for stimuli moving up and to the right. b A tuning curve graph of the responses of the same cell as a function of direction angle. The preferred direction and the “null” direction (direction opposite the preferred) are indicated. Adapted from [36, 78]