RAT RETINAL GANGLION CELLS: RECEPTIVE FIELD ORGANIZATION AND MAINTAINED ACTIVITY

Abstract

The receptive field organization of retinal ganglion cells of rats was explored with moving and stationary stimuli. Animals were anesthetized with urethane or phenobarbital or were prepared with a midbrain section and studied when unanesthetized. Responses were recorded with low impedance metal microelectrodes placed in the optic nerve or optic tract. Some of the receptive fields were concentrically arranged with on- or off-centers and antagonistic surrounds. Other units did not have demonstrable surrounds. The maintained activity of single retinal ganglion cells was studied in anesthetized and unanesthetized rats. In an unanesthetized rat, the maintained activity of a single unit was more or less random. Under barbiturate anesthesia, maintained activity characteristically showed a regular repetitive "bursting" pattern; bursts of several spikes were recorded at rates of 12 - 16/sec. This repetitive bursting activity was found to originate in the retina and was synchronized over a large part of the retina.