Preparing for the unexpected: predictive feedback boosts the response to unpredictable communication signals in weakly electric fish.

Abstract

Event Abstract Back to Event Preparing for the unexpected: predictive feedback boosts the response to unpredictable communication signals in weakly electric fish. Gary Marsat1* and Leonard Maler1 1 University of Ottawa, Cellular and Molecular Medicine & Centre for Neural Dynamics, Canada To interact with the environment efficiently, the nervous system must generate expectations about redundant sensory signals and detect unexpected ones. Neural circuits can, for example, compare a prediction of the sensory signal that was generated by the nervous system with the incoming sensory input, in order to generate a response selective to novel stimuli. This task is particularly important for communication signals where background must be suppressed for the signal to be reliably detected. We used the communication signals of the weakly electric fish to investigate the neural mechanism used to perform this task. We focus on communication signals –called small chirps– typical of male-male agonistic encounters. In addition to chirps, interacting fish are constantly exposed to redundant a sinusoidal amplitude modulation (beat) resulting from the interaction of the two fishes’ electric fields. Chirps must therefore be distinguished from the background beat by the nervous system. In the first order electrosensory neurons of electric fish, a negative image of low-frequency redundant communication signals is subtracted from the neural response via feedback, allowing unpredictable signals to be extracted (Marsat et al., 2012). The mechanism by which this canceling feedback is generated and operates is well understood and has been the focus of many studies. Here we show that the canceling feedback not only suppresses the predictable signal, but also actively enhances the response to the unpredictable communication signal. A mismatch between the canceling feedback and incoming sensory input causes both to become positive: at a phase where the soma is normally not depolarized by feedforward sensory inputs caused by the redundant beat, the unpredictable input transiently depolarizes it while the neuron’s apical dendrites are still depolarized by the lagging predictive feedback. The apical dendrites allow the backpropagation of somatic spikes, a mechanism that underlie the bursting propensity of the cell. Using in vivo intracellular dendritic recordings, we show that backpropagation is enhanced when the dendrites are depolarized by feedback. Therefore the soma is initially depolarized by the feedforward input from the chirp, a depolarization that is then increased by the enhanced backpropagating spike leading to the production of spike bursts. We conclude that the feedback driven by a predictable low-frequency signal not only suppresses the response to a redundant stimulus, but also induces a bursting response triggered by unpredictable communication signals. References Marsat G, Longtin A and Maler L. (2012) Cellular and circuit properties supporting different sensory coding strategies in electric fish and other systems. Curr Op Neurobiol, DOI:10.1016/j.conb.2012.01.009. Keywords: backpropagation, bursting, Communication signals, Feedback, sensory processing Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster Presentation (see alternatives below as well) Topic: Sensory: Electrosensory Citation: Marsat G and Maler L (2012). Preparing for the unexpected: predictive feedback boosts the response to unpredictable communication signals in weakly electric fish.. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00163 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Dr. Gary Marsat, University of Ottawa, Cellular and Molecular Medicine & Centre for Neural Dynamics, Ottawa, Canada, gary.marsat@mail.wvu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gary Marsat Leonard Maler Google Gary Marsat Leonard Maler Google Scholar Gary Marsat Leonard Maler PubMed Gary Marsat Leonard Maler Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.