title: Anesthetic action on extra-synaptic receptors: effects in neural population models of EEG activity.
abstract: The role of extra-synaptic receptors in the regulation of excitation and inhibition in the brain has attracted increasing attention. Because activity in the extra-synaptic receptors plays a role in regulating the level of excitation and inhibition in the brain, they may be important in determining the level of consciousness. This paper reviews briefly the literature on extra-synaptic GABA and NMDA receptors and their affinity to anesthetic drugs. We propose a neural population model that illustrates how the effect of the anesthetic drug propofol on GABAergic extra-synaptic receptors results in changes in neural population activity and the electroencephalogram (EEG). Our results show that increased tonic inhibition in inhibitory cortical neurons cause a dramatic increase in the power of both δ- and α- bands. Conversely, the effects of increased tonic inhibition in cortical excitatory neurons and thalamic relay neurons have the opposite effect and decrease the power in these bands. The increased δ-activity is in accord with observed data for deepening propofol anesthesia; but is absolutely dependent on the inclusion of extrasynaptic (tonic) GABA action in the model.
authors.affiliation: INRIA CR Nancy - Grand Est, Team Neurosys Villers-les-Nancy, France.
authors.forename: Meysam
authors.initials: M
authors.lastname: Hashemi
authors.affiliation: INRIA CR Nancy - Grand Est, Team Neurosys Villers-les-Nancy, France.
authors.forename: Axel
authors.initials: A
authors.lastname: Hutt
authors.affiliation: Department of Anaesthesiology, Waikato Clinical School, University of Auckland Hamilton, New Zealand.
authors.forename: Jamie
authors.initials: J
authors.lastname: Sleigh
keywords: GABA receptor; general anesthesia; neural mass; power spectrum; propofol