serval:BIB_5D6F13635D29
Consciousness and cortical responsiveness: a within-state study during non-rapid eye movement sleep.
10.1038/srep30932
000380930400001
27491799
Nieminen
J.O.
author
Gosseries
O.
author
Massimini
M.
author
Saad
E.
author
Sheldon
A.D.
author
Boly
M.
author
Siclari
F.
author
Postle
B.R.
author
Tononi
G.
author
article
2016-08-05
Scientific reports
2045-2322
2045-2322
journal
6
30932
When subjects become unconscious, there is a characteristic change in the way the cerebral cortex responds to perturbations, as can be assessed using transcranial magnetic stimulation and electroencephalography (TMS-EEG). For instance, compared to wakefulness, during non-rapid eye movement (NREM) sleep TMS elicits a larger positive-negative wave, fewer phase-locked oscillations, and an overall simpler response. However, many physiological variables also change when subjects go from wake to sleep, anesthesia, or coma. To avoid these confounding factors, we focused on NREM sleep only and measured TMS-evoked EEG responses before awakening the subjects and asking them if they had been conscious (dreaming) or not. As shown here, when subjects reported no conscious experience upon awakening, TMS evoked a larger negative deflection and a shorter phase-locked response compared to when they reported a dream. Moreover, the amplitude of the negative deflection-a hallmark of neuronal bistability according to intracranial studies-was inversely correlated with the length of the dream report (i.e., total word count). These findings suggest that variations in the level of consciousness within the same physiological state are associated with changes in the underlying bistability in cortical circuits.
Cerebral Cortex/physiology
Consciousness
Dreams/physiology
Electroencephalography
Female
Humans
Male
Neuronal Plasticity
Sleep/physiology
Sleep, REM/physiology
Synaptic Transmission
Transcranial Magnetic Stimulation
Wakefulness/physiology
eng
60_published
true
peer-reviewed
Publication types: Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
Publication Status: epublish
University of Lausanne
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