Evoked Alpha Power is Reduced in Disconnected Consciousness During Sleep and Anesthesia

Matthieu Darracq, Chadd M. Funk, Daniel Polyakov, Brady Riedner, Olivia Gosseries, Jaakko O. Nieminen, Vincent Bonhomme, Jean Francois Brichant, Melanie Boly, Steven Laureys, Giulio Tononi, Robert D. Sanders*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)
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Sleep and anesthesia entail alterations in conscious experience. Conscious experience may be absent (unconsciousness) or take the form of dreaming, a state in which sensory stimuli are not incorporated into conscious experience (disconnected consciousness). Recent work has identified features of cortical activity that distinguish conscious from unconscious states; however, less is known about how cortical activity differs between disconnected states and normal wakefulness. We employed transcranial magnetic stimulation–electroencephalography (TMS–EEG) over parietal regions across states of anesthesia and sleep to assess whether evoked oscillatory activity differed in disconnected states. We hypothesized that alpha activity, which may regulate perception of sensory stimuli, is altered in the disconnected states of rapid eye movement (REM) sleep and ketamine anesthesia. Compared to wakefulness, evoked alpha power (8–12 Hz) was decreased during disconnected consciousness. In contrast, in unconscious states of propofol anesthesia and non-REM (NREM) sleep, evoked low-gamma power (30–40 Hz) was decreased compared to wakefulness or states of disconnected consciousness. These findings were confirmed in subjects in which dream reports were obtained following serial awakenings from NREM sleep. By examining signatures of evoked cortical activity across conscious states, we identified novel evidence that suppression of evoked alpha activity may represent a promising marker of sensory disconnection.

Original languageEnglish
Article number16664
Pages (from-to)1-10
JournalScientific Reports
Issue number1
Publication statusPublished - 1 Dec 2018
MoE publication typeA1 Journal article-refereed


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