Bistability breaks-off deterministic responses to intracortical stimulation during non-REM sleep

Pigorini, A. et al. (2015) Bistability breaks-off deterministic responses to intracortical stimulation during non-REM sleep. NeuroImage, 112, pp. 105-113. (doi: 10.1016/j.neuroimage.2015.02.056) (PMID:25747918)

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During non-rapid eye movement (NREM) sleep (stage N3), when consciousness fades, cortico-cortical interactions are impaired while neurons are still active and reactive. Why is this? We compared cortico-cortical evoked-potentials recorded during wakefulness and NREM by means of time–frequency analysis and phase-locking measures in 8 epileptic patients undergoing intra-cerebral stimulations/recordings for clinical evaluation. We observed that, while during wakefulness electrical stimulation triggers a chain of deterministic phase-locked activations in its cortical targets, during NREM the same input induces a slow wave associated with an OFF-period (suppression of power > 20 Hz), possibly reflecting a neuronal down-state. Crucially, after the OFF-period, cortical activity resumes to wakefulness-like levels, but the deterministic effects of the initial input are lost, as indicated by a sharp drop of phase-locked activity. These findings suggest that the intrinsic tendency of cortical neurons to fall into a down-state after a transient activation (i.e. bistability) prevents the emergence of stable patterns of causal interactions among cortical areas during NREM. Besides sleep, the same basic neurophysiological dynamics may play a role in pathological conditions in which thalamo-cortical information integration and consciousness are impaired in spite of preserved neuronal activity.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Palva, Professor Matias
Authors: Pigorini, A., Sarasso, S., Proserpio, P., Szymanski, C., Arnulfo, G., Casarotto, S., Fecchio, M., Rosanova, M., Mariotti, M., Lo Russo, G., Palva, J. M., Nobili, L., and Massimini, M.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:NeuroImage
ISSN (Online):1095-9572
Published Online:04 March 2015
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in NeuroImage 112:105-113
Publisher Policy:Reproduced under a Creative Commons License

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