Responses of directionally selective neurons of the frog tectum mesencephali, their adaptation and extrapolation features.

Tectal directionally selective neurons were investigated in frogs. The highest measure of agreement in the character of response and dynamics of latent periods of neuron pairs was found with interelectrode distances of up to 300 mu, a fact which is evidently connected with the dimensions of the zones of ramification of the afferent fibers. Adaptation and extrapolation properties were discovered for most neurons and they were more marked in the nuclear layers of the tectum than in the fibrous layers. The more stable responses of neurons in the fibrous layers indicate the possible representation there of branches of fibers of the retinal ganglion cells, whereas neurons with high adaptivity (novelty neurons) are located in the nuclear layers.