Treatment-resistant depression (TRD) remains a major clinical challenge, with highly variable responses to ketamine. Immune activation characterizes a subset of patients with TRD. The kynurenine pathway (KP), which integrates immunometabolic signals with glutamatergic neurotransmission, may provide candidate biomarkers to inform personalized treatment. We investigated whether KP metabolites and...
Ketamine's antidepressant effects have been linked to its modulation of glutamatergic neurotransmission and synaptic plasticity. However, the precise roles of both glutamate (Glu) levels and brain-derived neurotrophic factor (BDNF) in this process remain incompletely understood. This study examined the relationship between ketamine-induced changes in Glu levels and peripheral BDNF levels using...
Ketamine is a dissociative anesthetic that induces a shift in global consciousness states and related brain dynamics. Portable low-density EEG systems could be used to monitor these effects. However, previous evidence is almost null and lacks adequate methods to address global dynamics with a small number of electrodes. This study delves into brain high-order interactions (HOI) to explore the...
The NMDA antagonist S-ketamine is gaining increasing use as a rapid-acting antidepressant, although its exact mechanisms of action are still unknown. In this study, we investigated ketamine in respect to its properties toward central noradrenergic mechanisms and how they influence alertness behavior. We investigated the influence of S-ketamine on the locus coeruleus (LC) brain network in a...
Subanesthetic doses of ketamine induce an antidepressant effect within hours in individuals with treatment-resistant depression while it furthermore induces immediate but transient psychotomimetic effects. Among these psychotomimetic effects, an altered sense of self has specifically been associated with the antidepressant response to ketamine as well as psychedelics. However, there is plenty...
Ketamine is a rapid-acting antidepressant that also influences neural reactivity to affective stimuli. However, the effect of ketamine on behavioral affective reactivity is yet to be elucidated. The affect-modulated startle reflex paradigm (AMSR) allows examining the valence-specific aspects of behavioral affective reactivity. We hypothesized that ketamine alters the modulation of the startle...
Abstract Ketamine shows rapid antidepressant effects peaking 24 h after administration. The antidepressant effects may occur through changes in glutamatergic metabolite levels and resting-state functional connectivity (rsFC) within the default mode network (DMN). A multistage drug effect of ketamine has been suggested, inducing acute effects on dysfunctional network configuration and delayed...
Along with its rapid therapeutic benefits, ketamine induces transient experience of dissociation during administration. Given the suggested association between ketamine-induced dissociation and treatment response, understanding the neural correlates of dissociation would help to elucidate its therapeutic mechanism. The posteromedial cortex (PMC) has been reported to play a vital role in the...