An efferent effect on a rhythmic response in the frog retina.
Extracellular recordings made from class III ganglion cells demonstrated a rhythmic bursting firing pattern in response to the offset of a mesopic level stimulus of 15, 30, and 90-s duration. The average bursting frequency was found to be 12.8 +/- 0.3 bursts per second. The bursts of action potentials had a duration of 0.047 +/- 0.002 s and separated by silent periods of 0.028 +/- 0.006 s. When a reversible cold block was applied to the optic chiasma, the rhythmic bursting pattern was replaced with a firing pattern that appeared random, indicating that efferent fibers to the retina might regulate the rhythmic response.
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