WIDE-FIELD NONDIRECTIONAL VISUAL UNITS IN THE PRETECTUM - DO THEY SUPPRESS OCULAR FOLLOWING OF SACCADE-INDUCED VISUAL-STIMULATION

1. Direction-selective neurons in the nucleus of the optic tract (NOT) provide motion signals for controlling ocular following responses. Wh en stimulated at low temporal and high spatial frequencies of motion ( slow speeds), these retinal-slip neurons produce directional responses . When stimulated by motion at high temporal and low spatial frequenci es (the visual conditions during saccades) the spontaneous activities of the neurons are inhibited by motion in all directions. A second cla ss of neurons in, or near, the NOT have large receptive fields, are no ndirectional, and are tuned to detect the same spatial and temporal st imuli that induce nondirectional inhibition in the retinal-slip neuron s. We suggest that the nondirectional cells provide an inhibitory inpu t for the retinal-slip neurons and therefore prevent ocular following of the visual displacements that accompany saccades.