Translational psychiatry
July 27, 2024
Rubén Herzog, Florentine Marie Barbey, Md Nurul Islam et al.
13 citations
Ketamine increases redundancy in brain dynamics—copies of the same information retrievable from three or more electrodes—most notably in the alpha frequency band, as measured by portable low-density EEG. In a double-blind crossover trial with 30 male adults, racemic ketamine compared to saline infusion produced greater redundancy during resting state, linked to dissociative shifts in consciousness. During an auditory oddball task, the effect was stronger for predictable standard stimuli than for deviant ones. Associations between ketamine's high-order interactions and experiences of derealization were observed, suggesting these measures capture pharmacological alterations in consciousness.
Neuroscience and biobehavioral reviews
July 1, 2024
Mina Kheirkhah, Allison C Nugent, Alicia A Livinski et al.
13 citations
Music and ketamine each influence therapeutic outcomes, yet their combined use is rarely studied. This scoping review maps existing research on administering music alongside ketamine or esketamine in humans. Studies include healthy volunteers and patients of various ages, using different doses and treatment processes, with music played at varying times relative to drug administration. Research on music during ketamine anesthesia is included, as anesthesia drove early ketamine use. Recreational ketamine studies are excluded. The review is limited to English-language articles with no year restriction. It is the first comprehensive overview of music and ketamine/esketamine interplay, offering guidance for future study design.
Research square
March 21, 2024
Agustin Ibanez, Ruben Herzog, Florentine Barbey et al.
1 citation
Ketamine increases redundancy in brain dynamics, particularly in the alpha frequency band, and this effect is more pronounced during resting state and associated with dissociative experiences. In a double-blinded cross-over design with 30 male adults, racemic ketamine was compared to saline infusion. Higher-order interactions (HOI) computed from EEG data showed that ketamine boosted redundancy, especially for predictable stimuli in an auditory oddball task. These findings suggest that ketamine-induced shifts toward dissociation correlate with increased redundancy in neural signal interactions, highlighting the potential of complexity measures with portable EEG for monitoring pharmacological changes in consciousness.
Zumrut Duygu Sen, Nitin Sharma, Lena Vera Danyeli et al.
preprint
Ketamine causes temporary dissociative experiences alongside its rapid therapeutic effects. This study examined whether pleasant and unpleasant dissociations can be predicted by functional connectivity of the posteromedial cortex (PMC) in 35 male participants during ultrahigh-field MRI. Pleasant dissociation (oceanic boundlessness) was predicted by PMC connections with control network regions at baseline and during infusion, and additionally with default mode network regions during infusion. Unpleasant dissociation (anxious ego dissolution) could not be predicted by PMC connectivity. The findings suggest distinct brain mechanisms for pleasant versus unpleasant dissociations, and that PMC connectivity changes may be a shared neural feature of dissociation from both ketamine and psychedelics.