Brain, behavior, and immunity
July 5, 2026
Bruno Pedraz-Petrozzi, Marta Marszalek-Grabska, Emilia Fornal et al.
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...
JAMA Network Open
June 1, 2026
Martin Walter, Christine Zu Eulenburg, Ani Damyanova et al.
1 citation
Ketamine exerts rapid antidepressant effects. However, currently available ketamine-based treatments are associated with dissociative and cardiovascular adverse effects. To evaluate the antidepressant efficacy and tolerability of KET01, a novel, oral, prolonged-release racemic ketamine tablet formulation. KET01-03 was an active-comparator, double-blind, double-dummy, crossover phase 1...
Frontiers in Psychiatry
September 2, 2025
Mina Kheirkhah, Nastasia McDonald, Julia Aepfelbacher et al.
1 citation
Introduction: This is the first randomized controlled trial to use both qualitative and quantitative methods to evaluate the effects of a combined sensory intervention that included mindfulness, music, and a light-occluding eye mask during antidepressant-dose ketamine treatment for depression. Methods: Forty-three participants with unipolar depressive disorder enrolled in the study; 22...
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
May 1, 2025
Mina Kheirkhah, Wallace C. Duncan, Qiaoping Yuan et al.
6 citations
Abnormalities during rapid eye movement (REM) sleep contribute to the pathophysiology of major depressive disorder (MDD), but few studies have explored the relationship between REM sleep and treatment-resistant depression (TRD). In MDD, REM sleep abnormalities often manifest as alterations in total night REM Density (RD), RD in the first REM period (RD1), and REM Latency (RL). Among these, RD1...
Frontiers in Psychiatry
2025
Leonard Marx, Zümrüt Duygu Sen, Lena Vera Danyeli et al.
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...
Translational Psychiatry
July 27, 2024
Rubén Herzog, Florentine Marie Barbey, Md Nurul Islam et al.
13 citations
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...
Neuroscience and Biobehavioral Reviews
July 1, 2024
Mina Kheirkhah, Allison C. Nugent, Alicia A Livinski et al.
13 citations
Music and ketamine are both known to affect therapeutic outcomes, but few studies have investigated their co-administration. This scoping review describes the existing literature on the joint use of music and ketamine-or esketamine (the S(+) enantiomer of ketamine)-in humans. The review considers that extant studies have explored the intersection of ketamine/esketamine and music in healthy...
The International Journal of Neuropsychopharmacology
June 1, 2024
Thomas Liebe, Lena Vera Danyeli, Zümrüt Duygu Sen et al.
5 citations
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...
Journal of Psychiatric Research
April 1, 2024
Lena Vera Danyeli, Zümrüt Duygu Sen, Lejla Colic et al.
3 citations
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...
Research Square
March 21, 2024
Agustin Ibanez, Rubén Herzog, Florentine Barbey et al.
1 citation
In a double-blinded cross-over design, 30 adults (mean age = 25.57, SD = 3.74; all male) were administered racemic ketamine and compared against saline infusion as a control. Both task-driven (auditory oddball paradigm) and resting-state EEG were recorded. HOI were computed using advanced multivariate information theory tools, allowing us to quantify nonlinear statistical dependencies between...
arXiv Preprint Archive
November 20, 2021
Dongmei Shi, Meng Li, Martin Walter et al.
Any macrosystem consists of many microparticles. According to statistical physics, the macroproperties of a system are realized as the statistical average of the corresponding microproperties. In our study, a model based on ensemble theory from statistical physics is proposed. Specifically, the functional connectivity (FC) patterns confirmed by Leading Eigenvector Dynamics Analysis (LEiDA) are...
Social Cognitive and Affective Neuroscience
April 13, 2016
Mick Lehmann, Erich Seifritz, Anke Henning et al.
58 citations
Distraction and rumination are distinct response styles that determine how an individual deals with negative thoughts and feelings. Rumination is accompanied by an elevated self-focus, which is associated with increased resting state functional connectivity and decreased reactivity within the default mode network. Interestingly, the NMDA receptor antagonist ketamine reduces functional...
Human Brain Mapping
February 25, 2016
Milan Scheidegger, Anke Henning, Martin Walter et al.
78 citations
Increased amygdala reactivity might lead to negative bias during emotional processing that can be reversed by antidepressant drug treatment. However, little is known on how N-methyl-d-aspartate (NMDA) receptor antagonism with ketamine as a novel antidepressant drug target might modulate amygdala reactivity to emotional stimulation. Using functional magnetic resonance imaging (fMRI) and...
Neural Plasticity
2016
Chuan-Chih Yang, Alfonso Barrós‐loscertales, Daniel Pinazo et al.
284 citations
The topic of investigating how mindfulness meditation training can have antidepressant effects via plastic changes in both resting state and meditation state brain activity is important in the rapidly emerging field of neuroplasticity. In the present study, we used a longitudinal design investigating resting state fMRI both before and after 40 days of meditation training in 13 novices. After...
PLoS One
September 24, 2012
Milan Scheidegger, Martin Walter, Mick Lehmann et al.
282 citations
Increasing preclinical and clinical evidence underscores the strong and rapid antidepressant properties of the glutamate-modulating NMDA receptor antagonist ketamine. Targeting the glutamatergic system might thus provide a novel molecular strategy for antidepressant treatment. Since glutamate is the most abundant and major excitatory neurotransmitter in the brain, pathophysiological changes in...
Pharmacopsychiatry
September 1, 2011
Simone Grimm, Milan Scheidegger, Anke Henning et al.
Ketamine is a potent glutamatergic NMDA receptor antagonist with rapid antidepressant properties, thus providing a valuable research tool for the investigation of the neurobiology of major depressive disorder (MDD). Increasing evidence underscores the role of glutamate dependent neuroplasticity and glutamatergic neurotransmission and metabolism in the pathophysiology of MDD. This multimodal...
Pharmacopsychiatry
September 1, 2011
Milan Scheidegger, Anke Henning, Martin Walter et al.
Background: Ketamine is a potent NMDA receptor antagonist with rapid antidepressant properties at subanaesthetic doses. This multimodal imaging study reveals the effects of a subanaesthetic ketamine infusion on fMRI-BOLD responses during an emotional processing task and their relationship to glutamatergic metabolite concentrations in the pregenual anterior cingulate cortex (PACC) assessed by...
Zümrüt Duygu Sen, Nitin Sharma, Lena Vera Danyeli et al.
preprint
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...