Biology subjects

Duclos, C.

Publications and source records attributed to Duclos, C..

2 recordsLinked to original sources

bioRxiv2022

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

The analysis of human EEG has traditionally focused on oscillatory power, which is characterized by peaks above an aperiodic component in the power spectral density. This study investigates the aperiodic EEG component of individuals in a disorder of consciousness (DOC); how it changes in response to exposure to anesthesia; and how it relates to the brains information richness and criticality. High-density EEG was recorded from 43 individuals in a DOC, with 16 of these individuals undergoing a protocol of propofol anesthesia. The aperiodic component was defined by the spectral slope of the power spectral density. Our results demonstrate that the EEG aperiodic component is more informative about the participants level of consciousness than the oscillatory component. Importantly, the pharmacologically induced change in the spectral slope from 30-45 Hz positively correlated with individuals pre-anesthetic level of consciousness. The pharmacologically induced loss of information-richness and criticality was associated with individuals pre-anesthetic aperiodic component. During exposure to anesthesia, the aperiodic component was correlated with 3-month recovery status for individuals with DOC. The aperiodic EEG component has been historically neglected; this research highlights the necessity of considering this measure for the assessment of individuals in DOC and future research that seeks to understand the neurophysiological underpinnings of consciousness.

neuroscience↗

bioRxiv2020

Brain network motifs are markers of loss and recovery of consciousness

Motifs are patterns of inter-connections between nodes of a network, and have been investigated as building blocks of directed networks. This study explored the re-organization of 3-node motifs during loss and recovery of consciousness. Nine healthy subjects underwent a 3-hour anesthetic protocol while 128-channel electroencephalography (EEG) was recorded. In the alpha (8-13 Hz) band, five-minute epochs of EEG were extracted for: baseline; induction; unconscious; 30-, 10- and 5-minutes pre-recovery of responsiveness; 30- and 180-minutes post-recovery of responsiveness. We constructed a functional brain network using the weighted and directed phase lag index, on which we calculated the frequency and topology of 3-node motifs. Three motifs (motifs 1, 2 and 5) were significantly present across participants and epochs, when compared to random networks (p<0.05). The topology of motifs 1 and 5 changed significantly between responsive and unresponsive epochs (p<0.01). Motif 1 was constituted by long-range chain-like connections, while motif 5 was constituted by short-range, loop-like connections. Our results suggest that anesthetic-induced unconsciousness is associated with a topological re-organization of network motifs. As motif topological re-organization may precede (motif 5) or accompany (motif 1) the return of responsiveness, motifs could contribute to the understanding of the neural correlates of consciousness.

neuroscience↗