Neurophysiological properties of the retinal ganglion cell classes of the Cuban treefrog, Hyla septentrionalis.

The properties of the retinal ganglion cell classes in the cuban treefrog Hyla septentrionalis were studied qualitatively and quantitatively. In the superficial layers of the optic tectum three main classes of afferent optic nerve fibers could be distinguished, class-1*, class-3 and class-4 neurons. Hyla displays a more "classical" organization of the receptive fields in class-1* neurons and a weaker inhibitory surround and lower thresholds with respect to velocity, size and contrast than in Bufo or ranid frogs. The functions for velocity, contrast, size of stimulus, neuronal adaptation and adaptation to background luminance level were evaluated. Experiments with monochromatic light spots are mentioned. The results are compared to those of other amphibia and the diversity of the retinal ganglion cell properties in the different species is stressed as an important factor in the processing of the various ganglion cell types at the tectal level.