Synaptic plasticity modulates autonomous transitions between waking and sleep states: Insights from a Morris-Lecar model
Authors: Ciszak M., Bellesi M.
Autors Affiliation: CNR – Istituto Nazionale di Ottica, Largo E. Fermi 6, 50125 Firenze, Italy
Abstract: The transitions between waking and sleep states are characterized by considerable changes in neuronal firing. During waking, neurons fire tonically at irregular intervals and a desynchronized activity is observed at the electroencephalogram. This activity becomes synchronized with slow wave sleep onset when neurons start to oscillate between periods of firing (up-states) and periods of silence (down-states). Recently, it has been proposed that the connections between neurons undergo potentiation during waking, whereas they weaken during slow wave sleep. Here, we propose a dynamical model to describe basic features of the autonomous transitions between such states. We consider a network of coupled neurons in which the strength of the interactions is modulated by synaptic long term potentiation and depression, according to the spike time-dependent plasticity rule (STDP). The model shows that the enhancement of synaptic strength between neurons occurring in waking increases the propensity of the network to synchronize and, conversely, desynchronization appears when the strength of the connections become weaker. Both transitions appear spontaneously, but the transition from sleep to waking required a slight modification of the STDP rule with the introduction of a mechanism which becomes active during sleep and changes the proportion between potentiation and depression in accordance with biological data. At the neuron level, transitions from desynchronization to synchronization and vice versa can be described as a bifurcation between two different states, whose dynamical regime is modulated by synaptic strengths, thus suggesting that transition from a state to an another can be determined by quantitative differences between potentiation and depression. (C) 2011 American Institute of Physics. [doi:10.1063/1.3657381]
Volume: 21 (4) Pages from: 043119 to: 043119
More Information: M.C. acknowledges a Marie Curie European Reintegration Grant (within a 7th European Community Framework Programme).DOI: 10.1063/1.3657381Citations: 7data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2019-09-08References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here