Evidence of trace conditioning in comatose patients revealed by the reactivation of EEG responses to alerting sounds.

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State: Public
Version: Author's accepted manuscript
Serval ID
serval:BIB_339C4617A9DA
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Evidence of trace conditioning in comatose patients revealed by the reactivation of EEG responses to alerting sounds.
Journal
NeuroImage
Author(s)
Juan E., Nguepnjo Nguissi N.A., Tzovara A., Viceic D., Rusca M., Oddo M., Rossetti A.O., De Lucia M.
ISSN
1095-9572 (Electronic)
ISSN-L
1053-8119
Publication state
Published
Issued date
01/11/2016
Peer-reviewed
Oui
Volume
141
Pages
530-541
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Abstract
Trace conditioning refers to a learning process occurring after repeated presentation of a neutral conditioned stimulus (CS+) and a salient unconditioned stimulus (UCS) separated by a temporal gap. Recent studies have reported that trace conditioning can occur in humans in reduced levels of consciousness by showing a transfer of the unconditioned autonomic response to the CS+ in healthy sleeping individuals and in vegetative state patients. However, no previous studies have investigated the neural underpinning of trace conditioning in the absence of consciousness in humans. In the present study, we recorded the EEG activity of 29 post-anoxic comatose patients while presenting a trace conditioning paradigm using neutral tones as CS+ and alerting sounds as UCS. Most patients received therapeutic hypothermia and all were deeply unconscious according to standardized clinical scales. After repeated presentation of the CS+ and UCS couple, learning was assessed by measuring the EEG activity during the period where the UCS is omitted after CS+ presentation. Specifically we assessed the 'reactivation' of the neural response to UCS omission by applying a decoding algorithm derived from the statistical model of the EEG activity in response to the UCS presentation. The same procedure was used in a group of 12 awake healthy controls. We found a reactivation of the UCS response in absence of stimulation in eight patients (five under therapeutic hypothermia) and four healthy controls. Additionally, the reactivation effect was temporally specific within trials since it manifested primarily at the specific latency of UCS presentation and significantly less before or after this period. Our results show for the first time that trace conditioning may manifest as a reactivation of the EEG activity related to the UCS and even in the absence of consciousness.

Keywords
Acoustic Stimulation/methods, Adult, Aged, Awareness, Brain/physiopathology, Coma/diagnosis, Coma/physiopathology, Conditioning (Psychology), Consciousness, Electroencephalography/methods, Female, Humans, Male, Auditory stimuli, Coma, EEG, Learning, Multivariate analysis, Trace conditioning
Pubmed
Web of science
Open Access
Yes
Create date
15/08/2016 12:59
Last modification date
20/08/2019 13:19
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