title: Subsecond Sensory Modulation of Serotonin Levels in a Primary Sensory Area and Its Relation to Ongoing Communication Behavior in a Weakly Electric Fish.
abstract: Serotonergic neurons of the raphe nuclei of vertebrates project to most regions of the brain and are known to significantly affect sensory processing. The subsecond dynamics of sensory modulation of serotonin levels and its relation to behavior, however, remain unknown. We used fast-scan cyclic voltammetry to measure serotonin release in the electrosensory system of weakly electric fish,Apteronotus leptorhynchus. These fish use an electric organ to generate a quasi-sinusoidal electric field for communicating with conspecifics. In response to conspecific signals, they frequently produce signal modulations called chirps. We measured changes in serotonin concentration in the hindbrain electrosensory lobe (ELL) with a resolution of 0.1 s concurrently with chirping behavior evoked by mimics of conspecific electric signals. We show that serotonin release can occur phase locked to stimulus onset as well as spontaneously in the ELL region responsible for processing these signals. Intense auditory stimuli, on the other hand, do not modulate serotonin levels in this region, suggesting modality specificity. We found no significant correlation between serotonin release and chirp production on a trial-by-trial basis. However, on average, in the trials where the fish chirped, there was a reduction in serotonin release in response to stimuli mimicking similar-sized same-sex conspecifics. We hypothesize that the serotonergic system is part of an intricate sensory-motor loop: serotonin release in a sensory area is triggered by sensory input, giving rise to motor output, which can in turn affect serotonin release at the timescale of the ongoing sensory experience and in a context-dependent manner.
authors.affiliation: Department of Cellular and Molecular Medicine, University of Ottawa , Ottawa, Ontario K1H 8M5, Canada.
authors.forename: Haleh
authors.identifier: 0000-0003-0372-4912
authors.initials: H
authors.lastname: Fotowat
authors.affiliation: Department of Cellular and Molecular Medicine, University of Ottawa , Ottawa, Ontario K1H 8M5, Canada.
authors.forename: Erik
authors.identifier: 0000-0002-4184-8919
authors.initials: E
authors.lastname: Harvey-Girard
authors.affiliation: Department of Anatomy and Neurobiology, Department of Psychiatry, University of Maryland , Baltimore, Maryland 21201.
authors.forename: Joseph F
authors.identifier: 0000-0001-5086-7559
authors.initials: JF
authors.lastname: Cheer
authors.affiliation: Department of Biology, McGill University , Montréal, Québec H3A 1B1, Canada.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Krahe
authors.affiliation: Department of Cellular and Molecular Medicine, University of Ottawa , Ottawa, Ontario K1H 8M5, Canada.
authors.forename: Leonard
authors.initials: L
authors.lastname: Maler
mesh_terms: D000161:Acoustic Stimulation; D000819:Animal Communication; D000818:Animals; D004558:Electric Stimulation; D023702:Gymnotiformes / Q000378:metabolism*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D010465:Perception / Q000502:physiology*; D012249:Rhombencephalon / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors
chemical_list: D012701:Serotonin
keywords: 5-HT; communication behavior; electrosensory; fast-scan cyclic voltammetry; serotonin; weakly electric fish