Transformation of context-dependent sensory dynamics into motor behavior

Latorre R, Levi R, Varona P (2013) Transformation of Context-dependent Sensory Dynamics into Motor Behavior. PLoS Comput Biol 9(2): e1002908. doi:10.1371/journal.pcbi.1002908The intrinsic dynamics of sensory networks play an important role in the sensory-motor transformation. In this paper we use conductance based models and electrophysiological recordings to address the study of the dual role of a sensory network to organize two behavioral context-dependent motor programs in the mollusk Clione limacina. We show that: (i) a winner take-all dynamics in the gravimetric sensory network model drives the typical repetitive rhythm in the wing central pattern generator (CPG) during routine swimming; (ii) the winnerless competition dynamics of the same sensory network organizes the irregular pattern observed in the wing CPG during hunting behavior. Our model also shows that although the timing of the activity is irregular, the sequence of the switching among the sensory cells is preserved whenever the same set of neurons are activated in a given time window. These activation phase locks in the sensory signals are transformed into specific events in the motor activity. The activation phase locks can play an important role in motor coordination driven by the intrinsic dynamics of a multifunctional sensory organThis work was supported by MINECO TIN2012-30883 and IPT-2011-0727-020000

Estudio de las firmas neuronales en los generadores centrales de patrones

Trabajo presentado para obtener el Diploma de Estudios Avanzados (DEA)

Mensajes colusivos en subastas con costos de entrada

Las subastas son mecanismos para asignar recursos ampliamente utilizados en diferentes países. No obstante están sujetas a actividades "ilegales" como la colusión que suele darse mediante acuerdos entre los distintos postores, los cuales pueden ser implícitos o explícitos. En este trabajo intentaremos encontrar un ejemplo donde el parloteo puede ser un medio efectivo para que al menos uno de los participantes (emisor) mejore su pago esperado en la subasta, a pesar de que el mensaje no tenga ningún costo asociado, no pueda tomarse como un compromiso ni como una amenaza para el otro participante, y que no exista efecto reputación.Auctions are widely used mechanisms to allocate resources in different countries. However they are subject to “illegal” activities such as collusion that usually takes the form of an implicit or explicit agreement among participants. In this paper we will try to find an example in which cheap-talk could be an effective tool for at least one bidder to have a betterexpected pay off. We obtain this result even though the signal is costless or does not take the form of an engagement or threat for the other participant and does has reputation effects.Fil: Gabrielli, Maria Florencia. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; ArgentinaFil: Latorre, Roberto. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas; Argentin

Sensory dynamics transformation into effective motor behavior

Abstracts from Twenty Second Annual Computational Neuroscience Meeting: CNS*2013 Paris, France. 13-18 July 2013This work was supported by MINECO TIN2012-30883 and IPT-2011-0727-020000

Channel-specific input/output transformations arising from the interaction between dynamic synapses and subthreshold oscillations

Authors acknowledge support by MINECO TIN2012-30883 and FIS2013-43201-P

Interplay between subthreshold oscillations and depressing synapses in single neurons

Latorre R, Torres JJ, Varona P (2016) Interplay between Subthreshold Oscillations and Depressing Synapses in Single Neurons. PLoS ONE 11(1): e0145830. doi:10.1371/journal.pone.0145830In this paper we analyze the interplay between the subthreshold oscillations of a single neuron conductance-based model and the short-term plasticity of a dynamic synapse with a depressing mechanism. In previous research, the computational properties of subthreshold oscillations and dynamic synapses have been studied separately. Our results show that dynamic synapses can influence different aspects of the dynamics of neuronal subthreshold oscillations. Factors such as maximum hyperpolarization level, oscillation amplitude and frequency or the resulting firing threshold are modulated by synaptic depression, which can even make subthreshold oscillations disappear. This influence reshapes the postsynaptic neuron's resonant properties arising from subthreshold oscillations and leads to specific input/output relations. We also study the neuron's response to another simultaneous input in the context of this modulation, and show a distinct contextual processing as a function of the depression, in particular for detection of signals through weak synapses. Intrinsic oscillations dynamics can be combined with the characteristic time scale of the modulatory input received by a dynamic synapse to build cost-effective cell/channel-specific information discrimination mechanisms, beyond simple resonances. In this regard, we discuss the functional implications of synaptic depression modulation on intrinsic subthreshold dynamics.This work was supported by MINECO TIN2012-30883 (RL and PV) and FIS2013-43201-P (JJT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Firmas neuronales y multicódigos en neuronas con comportamiento en ráfagas

Tesis doctoral inédita. Universidad Autónoma de Madrid, Escuela Politécnica Superior, junio de 200

Origin and role of neural signatures in bursting neurons

Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.A traditional view in neuroscience is that information arriving through one channel, i.e. a synapse, is encoded through a single code in the signal, e.g., the rate or the precise timing of the incoming events. However, not all the neural readers have to be interested in the same aspect of a common input signal, especially in multifunctional networks that can take advantage of several simultaneous codes. Multiple codes can be used to discriminate or contextualize certain inputs, even in single neurons. Dynamical mechanisms can add to the existing hard-wired connectivity for this task. Recent experiments have revealed the existence of neural signatures in the activity of bursting cells of invertebrate central pattern generators. These signatures consist of cell-specific spike timings in the bursting activity of the neurons. The signatures coexist with the information encoded in the frequency and/or phase relationships of the slow waves. The functional role of these neural fingerprints is still unclear. Based on experiments and using conductance-based models, we discuss the origin and the role of neural signatures as a part of a multicoding strategy for single cells in different types of neural circuits.This work was supported by Fundacion BBVA, MEC BFU2006-07902/BFI and MEC TIN2004-04363-C03-03

Effect of individual spiking activity on rhythm generation of central pattern generators

This is the author’s version of a work that was accepted for publication in Neurocomputing. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Neurocomputing 58-60 (2004):10.1016/j.neucom.2004.01.091Central Pattern Generators (CPGs) are highly specialized neural networks often with redundant elements that allow the system to act properly in case of error. CPGs are multifunctional circuits, i.e. the same CPG can produce many di®erent rhythms in response to modulatory or sensory inputs. All these rhythms have to be optimal for motor control and coordination. In this paper, we use a model of the well-known pyloric CPG of crustacean to analyze the importance of redundant connections and individual spiking activity in the generation of the CPG rhythm. In particular, we study the e®ect of di®erent spike distributions of a neuron on the collective behavior of the CPG.This work was supported by the Spanish MCyT (BFI-2000- 0157 and TIC 2002-572-C02-02

Transient dynamics and rhythm coordination of inferior olive spatio-temporal patterns

This Document is protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.The inferior olive (IO) is a neural network belonging to the olivo-cerebellar system whose neurons are coupled with electrical synapses and display subthreshold oscillations and spiking activity. The IO is frequently proposed as the generator of timing signals to the cerebellum. Electrophysiological and imaging recordings show that the IO network generates complex spatio-temporal patterns. The generation and modulation of coherent spiking activity in the IO is one key issue in cerebellar research. In this work, we build a large scale IO network model of electrically coupled conductance-based neurons to study the emerging spatio-temporal patterns of its transient neuronal activity. Our modeling reproduces and helps to understand important phenomena observed in IO in vitro and in vivo experiments, and draws new predictions regarding the computational properties of this network and the associated cerebellar circuits. The main factors studied governing the collective dynamics of the IO network were: the degree of electrical coupling, the extent of the electrotonic connections, the presence of stimuli or regions with different excitability levels and the modulatory effect of an inhibitory loop (IL). The spatio-temporal patterns were analyzed using a discrete wavelet transform to provide a quantitative characterization. Our results show that the electrotonic coupling produces quasi-synchronized subthreshold oscillations over a wide dynamical range. The synchronized oscillatory activity plays the role of a timer for a coordinated representation of spiking rhythms with different frequencies. The encoding and coexistence of several coordinated rhythms is related to the different clusterization and coherence of transient spatio-temporal patterns in the network, where the spiking activity is commensurate with the quasi-synchronized subthreshold oscillations. In the presence of stimuli, different rhythms are encoded in the spiking activity of the IO neurons that nevertheless remains constrained to a commensurate value of the subthreshold frequency. The stimuli induced spatio-temporal patterns can reverberate for long periods, which contributes to the computational properties of the IO. We also show that the presence of regions with different excitability levels creates sinks and sources of coordinated activity which shape the propagation of spike wave fronts. These results can be generalized beyond IO studies, as the control of wave pattern propagation is a highly relevant problem in the context of normal and pathological states in neural systems (e.g., related to tremor, migraine, epilepsy) where the study of the modulation of activity sinks and sources can have a potential large impact.Roberto Latorre, Carlos Aguirre, and Pablo Varona were supported by MINECOTIN 2012-30883 and MikhailI. Rabinovich by ONRGrantN00014310205