Figure 4.

Control-response neuron with integrative surround modulation. Panel arrangements and conventions are same as in Figure 3. A, Responses to corner stimuli. The corner response was strongest when the global direction was up and to the right (the P global direction). The direction of the averaged corner response vectors is the global prediction (blue arrow). B, Responses to contour stimuli. For this neuron, the local motion was rightward for the P direction, and hence the PP global direction was down and to the right. The motion of the contour centered within the CRF was the same for P and PP directions. Responses to the P direction were larger than to the PP direction indicating integrative surround modulation. The direction of the averaged contour response vectors is the contour preferred direction (red arrow). C, We classified this neuron as a control-response neuron since control stimuli elicited weak but significant responses. D, Directional tuning measured with drifting gratings. The motion of the contour within the CRF (i.e., the local motion) was leftward or rightward and hence responses to those two directions were used to produce the local prediction (green arrow). Responses to rightward motion were stronger than to leftward motion and hence the local prediction points rightward. E, The contour preferred direction (red arrow) is superimposed on the local (green arrow) and global (blue arrow) predictions. The contour preferred direction is biased away from the local prediction toward the global prediction indicating integrative surround modulation.