title: A role of electrical inhibition in sensorimotor integration.
abstract: Although it is accepted that extracellular fields generated by neuronal activity can influence the excitability of neighboring cells, whether this form of neurotransmission has a functional role remains open. In vivo field effects occur in the teleost Mauthner (M)-cell system, where a combination of structural features support the concept of inhibitory electrical synapses. A single spike in one M-cell evoked within as little as 2.2 ms of the onset of an abrupt sound, simulating a predatory strike, initiates a startle-escape behavior [Zottoli SJ (1977) J Exp Biol 66:243-254]. We show that such sounds produce synchronized action potentials in as many as 20 or more interneurons that mediate feed-forward electrical inhibition of the M-cell. The resulting action currents produce an electrical inhibition that coincides with the electrotonic excitatory drive to the M-cell; the amplitude of the peak of the inhibition is approximately 40% of that of the excitation. When electrical inhibition is neutralized with an extracellular cathodal current pulse, subthreshold auditory stimuli are converted into ones that produce an M-spike. Because the timing of electrical inhibition is often the same as the latency of M-cell firing in freely swimming fish, we conclude that electrical inhibition participates in regulating the threshold of the acoustic startle-escape behavior. Therefore, a field effect is likely to be essential to the normal functioning of the neural network.
authors.affiliation: Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Shennan A
authors.initials: SA
authors.lastname: Weiss
authors.forename: Thomas
authors.initials: T
authors.lastname: Preuss
authors.forename: Donald S
authors.initials: DS
authors.lastname: Faber
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004560:Electricity; D005399:Fishes / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D055139:Sensory Gating / Q000502:physiology; D013550:Swimming / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*; D013997:Time Factors; D014867:Water
chemical_list: D014867:Water