Ketamine-Induced Unresponsiveness Shows a Harmonic Shift from Global to Localised Functional Organisation
bioRxiv (Cold Spring Harbor Laboratory) June 25, 2024 Milan van Maldegem, Jakub Vohryzek, Selen Atasoy et al. 2 citations preprint
Ketamine, a dissociative anesthetic, produces different brain dynamics at anesthetic versus sub-anesthetic doses. Using connectome harmonic decomposition (CHD) to analyze resting-state fMRI data from volunteers during ketamine-induced unresponsiveness, the study found increased prevalence of localized harmonics, similar to patterns seen in psychedelic states induced by LSD or psilocybin. This contrasts with traditional GABAergic sedation (e.g., propofol), where global harmonics increase with higher doses. The results indicate that ketamine-induced unresponsiveness does not necessarily suppress conscious experience and influences connectome harmonics oppositely to GABAergic hypnotics. CHD may track alterations in conscious awareness rather than behavioral responsiveness.