Event Abstract Back to Event Slow inhibition controls the representation of conditioning stimulus duration by the cerebellar granulle cells Ivan Herreros-Alonso1*, Andrea Giovannucci1 and Paul S. Verschure1, 2 1 Universitat Pompeu Fabra, SPECS - Synthetic Perceptive, Emotive and Cognitive Systems, Spain 2 Institució Catalana de Recerca i Estudis Avançats, Research Professor, Spain During delay eye-blink conditioning a set of Purkinje cells (PC) in the cerebellar cortex respond with a decrease in their simple spike firing rate, the so-called PC conditioned response (PC-CR). The PC-CR is adaptively timed to the expected arrival of the unconditioned stimulus (US). The acquisition mechanism of the PC-CR is still under debate. A family of models propose that the granular layer encodes time while the molecular layer, through supervised learning, associates this code with an error signal conveyed by the climbing fibers (cf), leading to the production of well-time anticipatory PC-CRs. According to such models, learning in the molecular layer is explained by long term plasticity at the parallel fiber (pf) to PC synapse. What remains to be explained is how the granular layer encodes time during the presentation of the conditioning stimulus (CS). Cerebellar glomeruli are a unique structure within the CNS because of the glial encapsulation of multiple synaptic contacts. This encapsulation assures that the extracellular concentration of spilled-over neurotransmitters remains high. We propose that the change in extracellular GABA concentration within the glomeruli might code CS durations in the 1 second range. Namely, due to the enhanced spill-over inhibition during the CS, the activity of the Granule Cell (GC) population will decrease thus encoding the time elapsed since the stimulus onset in its decaying amplitude. We test this prediction with a computational model of the granular layer. With information theory techniques we assess how the features of the slow inhibitory currents affect the representation of time in the GC output. Furthermore, exploiting the classical PC-perceptron analogy, we show that a perceptron can produce well-timed responses when trained on the output of the granular layer model. Summarising, on the one hand we demonstrate that the spill-over of Golgi-released GABA modulates the activity of the GC population such that it can code CS durations in the 1 second range. On the other hand, by showing that the information can be decoded by a linear combination of the pf activity, we demonstrate that a PC could acquire well-timed CRs on the basis of this analog representation of time in the pfs. Keywords: Cerebellum Conference: The Cerebellum: from neurons to higher control and cognition, Pavia, Italy, 8 Jul - 9 Jul, 2010. Presentation Type: Poster Presentation Topic: The Cerebellum: from neurons to higher control and cognition Citation: Herreros-Alonso I, Giovannucci A and Verschure PS (2010). Slow inhibition controls the representation of conditioning stimulus duration by the cerebellar granulle cells. Front. Neurosci. Conference Abstract: The Cerebellum: from neurons to higher control and cognition. doi: 10.3389/conf.fnins.2010.83.00011 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: 18 Aug 2010; Published Online: 29 Aug 2010. * Correspondence: Dr. Ivan Herreros-Alonso, Universitat Pompeu Fabra, SPECS - Synthetic Perceptive, Emotive and Cognitive Systems, Barcelona, Spain, ivanherreros@gmail.com 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 Ivan Herreros-Alonso Andrea Giovannucci Paul S Verschure Google Ivan Herreros-Alonso Andrea Giovannucci Paul S Verschure Google Scholar Ivan Herreros-Alonso Andrea Giovannucci Paul S Verschure PubMed Ivan Herreros-Alonso Andrea Giovannucci Paul S Verschure 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.