Neuronal synchrony during anaesthesia - A thalamocortical model

¹ Lancaster University

^* To whom correspondence should be addressed. E-mail: aneta{at}lancaster.ac.uk.

Submitted on April 2, 2008
Revised on May 13, 2008
Accepted on 29 May 2008

	Abstract

There is growing evidence in favour of the temporal coding hypothesis that temporal correlation of neuronal discharges may serve to bind distributed neuronal activity into unique representations and, in particular, that (3.5-7.5 Hz) and (0.5-3.5 Hz oscillations facilitate information coding. The and rhythms are shown to be involved in various sleep stages, and during anaesthesia, and they undergo changes with the depth of anaesthesia. We introduce a thalamocortical model of interacting neuronal ensembles to describe phase relationships between and oscillations, especially during deep and light anaesthesia. Asymmetric and long range interactions among the thalamocortical neuronal oscillators are taken into account. The model results are compared with the experimental observations of Musizza et al. J. Physiol. (London) 2007 580:315-326. The and activities are found to be separately generated and are governed by the thalamus and cortex respectively. Changes in the degree of intra-ensemble and inter-ensemble synchrony imply that the neuronal ensembles inhibit information coding during deep anaesthesia and facilitate it during light anaesthesia.

Key Words: Neuronal oscillation, anaesthesia, asymmetric interactions, coupled oscillators, temporal coding, thalamocortical model