Slow dark discharge rhythms of cat retinal ganglion cells.

Abstract

Cat retinal ganglion cells fire in a slow rhythmic manner in the dark. The rates of these rhythms are extremely slow, ranging from 2/min. to 2/hr. They are characterized by sudden changes in rate between 2 more slowly changing levels of activity. Slow rhythms are abolished at moderate levels of illumination (lum. 5 cd/m2). They are present after section of the optic nerve. Slow rhythms from cells from the same eye are synchronized so that one can observe slow rhythms by recording the amplitude of the massed activity from the optic disk or nerve. The slow rhythms from the 2 eyes are not synchronized, but are similar in pattern. Electrical stimulation of the optic tract does not abolish or reset the rhythms but does influence them. The evidence presented suggests that these slow rhythms are generated in the retina.