Fig. 1.

Histological reconstruction of recording sites. A: line drawing and representative histological section stained for Nissl substance to demonstrate location of electrode tracks. An electrode track reconstructed from histological section is indicated (- - -). → (bottom), an electrode track that was located in the rostrocaudal extent of the pretectum at the level of the pretectal olivary nucleus (PON). NOT, nucleus of the optic tract; PULV, pulvinar. Scale bar = 1 mm. B: response properties of a representative NOT neuron during horizontal large-field visual motion presented on a tangent screen while the monkey (Macaca mulatta) fixated a stationary target spot. A strong direction-selective response occurs at short latency (50 ms) after the start of leftward visual motion. C: directional tuning data for a representative NOT neuron. Large-field visual motion was presented in different directions while the monkeys fixated a stationary target. The average firing rate is indicated at 45° intervals (●), with a curve fit to estimate the direction preference for the unit.