Photoreceptor action potentials

Abstract

Light-induced biochemical processes in mammalian photoreceptors cause graded hyperpolarization of these neurons, which are commonly thought to be non-spiking. Researchers from Fujita Health University in Japan, however, have studied these cells electrophysiologically in surgically excised retina and found that human rod photoreceptors do fire sodium-ion action potentials in response to injection of depolarizing currents. Additionally, spikes were observed at the termination of light stimuli, which amplifies an ‘off’ response by resulting in more neurotransmitter release. The full paper appears in the May issue of Neuron. LO