A correlation between receptive field properties and morphological structures in the pretectum of the cat.

Retinal terminals in the pretectum were labelled by anterograde axonal transport of horseradish peroxidase (HRP) after injecting the enzyme into one eye. Pretectal neurons were retrogradely labelled by HRP-injections into the dorsal cap of the inferior olive. Electrophysiological recordings were performed in the same animal. This procedure showed that direction-selective neurons in the nucleus of the optic tract (NOT) projecting to the dorsal cap of the inferior olive lie dorsal and lateral to the retinal terminal clusters. Direction-unselective neurons sensitive to high stimulus velocities (jerk-neurons) were localized within the areas of retinal terminal clusters. Both jerk-neurons and retinal terminal clusters never overlapped with retrogradely labelled neurons. Latency measurements to stimulation of the optic chiasm (OX) confirmed a monosynaptic W-cell projection to the direction-selective NOT cells and indicated a predominantly monosynaptic Y-cell projection to the jerk-neurons.