Biological Psychiatry Global Open Science
October 17, 2024
Nicco Reggente, Christian Kothe, Tracy Brandmeyer et al.
15 citations
Decoding self-reported meditative depth from EEG recordings is feasible. Expert Vipassana meditators (34 people) reported their depth on a 1–5 scale during two sessions, using either traditional probing or a novel spontaneous emergence method. Machine learning models fused spatial, spectral, and connectivity information from theta, alpha, and gamma bands to predict depth across unseen sessions. The spontaneous emergence method produced more frequent reports and correlated better with post-session outcomes than probing. No single EEG channel or default mode network region captured the complex neural dynamics; multivariate patterns were necessary. The findings suggest potential improvements for neurofeedback in meditation.
Biological Psychiatry Global Open Science
July 1, 2024
Julia Aepfelbacher, Benjamin Panny, Rebecca B Price
13 citations
Ketamine infusion strongly induced feelings of awe in people with depression, and these awe experiences consistently predicted and mediated improvements in depression scores over 1 to 30 days, unlike general dissociative effects, which did not mediate outcomes. In a study of 116 participants with depression, 77 received a ketamine infusion and 39 received saline placebo. Awe was measured 40 minutes after infusion, and depression severity was assessed at five time points afterward. Awe scores were significantly higher in the ketamine group and statistically mediated the relationship between ketamine and depression improvement at all time points, suggesting that the awe-inspiring properties of ketamine may contribute to its antidepressant effects.
Biological Psychiatry Global Open Science
November 1, 2024
Dhakshin Ramanathan, Jason Nan, Gillian Grennan et al.
10 citations
Consistency of response times during a breath-monitoring task, measured with electroencephalography in 324 people aged 15 to 91, correlates with attentive performance on an exteroceptive inhibitory control task. On-task alpha band activity (8-12 Hz) was greater than at rest. Low-consistency and longer breath responses were associated with elevated brain activity, particularly in posterior default mode network (pDMN) regions. pDMN activity was inversely linked with functional connectivity to frontal networks during the task but not at rest, suggesting frontal networks regulate pDMN activity during interoceptive attention. Greater pDMN activity in the precuneus was linked to lower subjective mindfulness and was adaptively modulated by task difficulty. Elevated pDMN alpha activity serves as an objective neural marker for low-consistency responding during interoceptive breath attention.
Biological Psychiatry Global Open Science
November 1, 2024
Isaac N Treves, Hilary A Marusak, Alexandra Decker et al.
7 citations
A significant finding reveals that adolescents with higher trait mindfulness experience lower anxiety and depression symptoms. An analysis of 106 adolescents, ages 12 to 15, identified a reliable brain state characterized by hyperconnectivity, showing an intraclass correlation coefficient of 0.65. This state, marked by elevated positive connectivity between networks, was positively correlated with self-reported trait mindfulness. While most dynamic brain states were unreliable across scans, this hyperconnected state may reflect enhanced awareness and arousal in those exhibiting higher mindfulness traits.
Biological Psychiatry Global Open Science
January 1, 2024
Victorita E. Ivan, David P Tomàs-Cuesta, Ingrid M. Esteves et al.
7 citations
Ibogaine, a psychedelic compound, destabilizes the cognitive map in the retrosplenial cortex of mice when they must infer their position between tactile landmarks. Using two-photon microscopy, researchers recorded neural activity in head-fixed mice running on a treadmill before and after ibogaine injection (40 mg/kg intraperitoneally). The drug increased neural activity rates, disrupted correlation structure, and heightened responses to cues, while leaving the size-frequency distribution of network activity events largely unchanged. These findings suggest that psychedelics disrupt representations that constrain neocortical activity, increasing neural signaling entropy. The loss of position encoding between landmarks resembles effects of hippocampal impairment, indicating that disruption of cognitive maps may contribute to discoordinated neocortical activity in psychedelic states.
Biological Psychiatry Global Open Science
July 1, 2025
Benjamin Brake, Lillian Wieder, Natasha Hughes et al.
5 citations
Dissociative states—disruptions in awareness and perception—occur across many psychiatric conditions and can be modeled in the lab. A meta-analysis of 123 studies (6,692 individuals) measured state dissociation using a standardized scale. At baseline, the largest effects were in dissociative and complex subtypes of posttraumatic stress disorder. In controlled experiments, mirror gazing and several drugs, particularly ketamine and cannabis, induced dissociation as high as or higher than that seen in PTSD. Results were highly variable across studies but not explained by methodological differences. These findings validate experimental methods for inducing dissociation and inform monitoring of adverse events in drug-based interventions.
Biological Psychiatry Global Open Science
July 1, 2025
Oussama Abdoun, Arnaud Poublan-Couzardot, Stéphane Offort et al.
5 citations
Most meditation research uses trait questionnaires that miss moment-to-moment changes during practice. The Lyon Assessment of Meditation Phenomenology (LAMP) questionnaire was developed to capture contextual, emotional, bodily, attentional, cognitive, and metacognitive dimensions of meditation. Fifty-three experienced meditators completed the LAMP after each session during a 10-day retreat. Over 60% of the assessed dimensions changed significantly over time, with distinct trajectories depending on meditation type (focused attention vs. open monitoring) and individual expertise. Three clusters of individual trajectories emerged, linked to prior experience and difficulties during the retreat. Findings on pain regulation were replicated and extended. This approach offers a rich, dynamic characterization of meditative experience.
Biological Psychiatry Global Open Science
March 1, 2025
Abigail E. Calder, Clifford Qualls, Gregor Hasler et al.
5 citations
The Hallucinogen Rating Scale (HRS) is a widely used questionnaire for measuring subjective effects of psychedelics and other psychoactive drugs. By analyzing 991 questionnaires from 18 studies involving 13 substances, researchers identified 8 factors with good internal consistency that map onto psychedelic effects. The factor model fit the data better than previous models and showed dose responses for most drugs. Patterns on the 8 factors clearly distinguished classic psychedelics (psilocybin, DMT) from dissociatives (ketamine, salvinorin A), empathogens (MDMA), stimulants (methylphenidate, amphetamine), and THC. The meaningfulness factor uniquely differentiated psychedelics from all other substances, supporting the HRS as a psychometrically sound tool for measuring drug-induced altered states.
Biological Psychiatry Global Open Science
September 1, 2025
Čestmír Vejmola, Klára Šíchová, Kateřina Syrová et al.
4 citations
Psilocin, the active compound in psychedelic mushrooms, impairs the ability to distinguish between static and moving images in both humans and rats. In a visual discrimination task, human participants and male rats were asked to judge whether an image was static or moving. Under psilocin, both species showed significant difficulty in this task. In humans, the impairment tracked psilocin plasma levels and self-reported hallucination intensity. In rats, psilocin selectively disrupted performance in a motion-based task but not a luminance-based task, suggesting a specific effect on motion perception. Decision time was also linked to discrimination impairment. This is the first evidence that rats experience visual distortions similar to those reported by humans, offering a model for studying altered visual perception in drug-induced and psychiatric conditions.
Biological Psychiatry Global Open Science
July 1, 2025
Shuang Li, Anhang Jiang, Xuefeng Ma et al.
3 citations
Internet gaming disorder (IGD) is a global mental health issue, and effective treatments remain challenging. In a study of 61 participants with IGD, 30 received mindfulness meditation (MM) training and 31 received progressive muscle relaxation (PMR) over eight sessions. Using resting-state functional MRI and dynamic network analysis of 142 brain regions, MM training significantly reduced addiction severity and cravings compared to PMR, which showed only nonspecific effects. MM increased brain network recruitment in the frontoparietal and basal ganglia networks while decreasing it in the default mode network, and increased integration between the frontoparietal-default mode and default mode-limbic networks. MM may improve top-down control, cognitive and emotional functions, and reward processing through reconfiguration of these neural pathways.
Biological Psychiatry Global Open Science
May 1, 2026
Mario Bogdanov, Jason N Scott, Shiba M Esfand et al.
1 citation
A single low dose of ketamine improves the ability to learn from rewards in both people with treatment-resistant depression and stressed rats, using nearly identical tasks. Twenty-four hours after receiving ketamine, individuals with treatment-resistant depression and chronically stressed rats showed a stronger tendency to choose the more frequently rewarded option, matching the performance of healthy controls. This effect was most pronounced in people with more severe anhedonia at the start. Ketamine did not affect general task accuracy, indicating it selectively boosts reward learning rather than overall performance. These findings point to a shared behavioral mechanism by which ketamine alleviates anhedonia, with potential implications for treating anhedonia in depression and related conditions.
Biological Psychiatry Global Open Science
March 1, 2026
Noam Goldway, Taly Markovits, Naomi Fine et al.
1 citation
Dissociation—feeling detached from one's body, environment, or self—often accompanies posttraumatic stress disorder (PTSD), but its neural basis is poorly understood. Using network control theory on resting-state functional MRI data, researchers examined brain dynamics during dissociative states in healthy volunteers given ketamine (n=30) and in PTSD patients (n=78) before and after treatment. Ketamine induced brain dynamics similar to those in untreated PTSD patients: increased dominance of the default mode network (DMN) meta-state and decreased dominance of the somatomotor network (SOM) meta-state. After treatment, reduced DMN meta-state dominance correlated with fewer dissociative symptoms. Treated patients also showed more organized, less entropic brain states, though ketamine did not significantly alter entropy indices. Dissociative states, whether drug-induced or clinical, involve increased DMN and reduced SOM dominance.
Biological Psychiatry Global Open Science
July 1, 2025
Stephen A Murata, Zachary B Madaj, Colt D Capan et al.
1 citation
Higher baseline levels of anthranilic acid (AA), a metabolite in the kynurenine pathway, predicted remission in patients with treatment-resistant depression receiving intravenous ketamine. In an open-label trial of 74 patients, 52% achieved remission after three infusions. Composite ratios of AA to intercellular adhesion molecule-1 and AA to tryptophan improved predictive accuracy over AA alone. The findings suggest that immunometabolic biomarkers could guide personalized ketamine treatment.
Biological Psychiatry Global Open Science
June 4, 2026
Petr Adámek, Veronika Rudolfová, Kristýna Malenínská et al.
A proposed framework, the Perceptual Theory of Schizophrenia (PerTh), contends that instability in retinal dopamine signaling may initiate a subset of schizophrenia cases. Retinal dopamine normally controls visual gain and spatial frequency processing; genetic liabilities for schizophrenia are argued to converge on retinal dopamine homeostasis, producing corrupted sensory input. This noisy signal is proposed to cascade through thalamocortical pathways, disrupting salience formation and driving compensatory synaptic changes that leave weak connections vulnerable to pruning. The theory aims to explain symptom timing, the predominance of auditory over visual hallucinations, and heterogeneity, without replacing existing models, and generates testable predictions about retinal function in psychosis.
Biological Psychiatry Global Open Science
May 14, 2026
Anne Maj van der Velden, Jakub Vohryzek, Paulina Clara Dagnino et al.
Mindfulness-based cognitive therapy (MBCT) alters brain network dynamics during depressive rumination in people with recurrent depression. In a randomized controlled trial with 48 participants, those who received MBCT plus treatment as usual showed changes in the occurrence frequency of a 'salience-somatomotor' brain state during rumination compared to those receiving treatment as usual alone. These neural changes were linked to reduced rumination after treatment and fewer depressive symptoms three months later. The findings suggest that MBCT may work by modifying how the brain's somatosensory and salience networks interact during rumination, offering clues about the brain mechanisms underlying treatment response.
Biological Psychiatry Global Open Science
July 1, 2025
Yalin Sun, Meenalochani Sivasubramanian, Marija Milenkovic et al.
Adolescent cannabis use increases risk for neuropsychiatric disorders, possibly through amygdala dysfunction. Chronic THC treatment in male adolescent nonhuman primates and rats disrupted sleep and increased anxiety-related behavior. THC activated proinflammatory glial cells (astrocytes) exclusively in the adolescent amygdala, upregulating GFAP and complement factor-B, effects absent in adults or other brain regions. THC also reduced synaptic plasticity markers stathmin-1 and NrCAM. Co-administered cannabidiol prevented astrocyte inflammation but did not restore plasticity markers. Astrogliosis correlated with fragmented sleep, attenuated plasticity markers with anxiety. Elevated CB1R expression in the maturing brain was astrocyte-localized in the amygdala, linking THC to unique adolescent amygdala vulnerability.
Biological Psychiatry Global Open Science
July 1, 2025
Paul S Myles, Jayashri Kulkarni, Jessica Kasza et al.
In a phase 2b randomized, double-blind trial, 81 adults with major depressive disorder received either nitrous oxide (at 25% or 50% inspired concentration) or an oxygen/air control across four weekly one-hour sessions, with four additional weeks of follow-up. The primary outcome, change in Hamilton Depression Rating Scale scores over the four treatment weeks, was lower with nitrous oxide than control (mean difference -1.9, 95% CI -3.9 to 0.0, p = .051), a result that did not reach conventional statistical significance. However, in the first week, 38% of the nitrous oxide group versus 13% of the control group achieved remission (p = .031). Secondary measures of depression and suicidality also favored nitrous oxide. The findings suggest nitrous oxide likely has beneficial antidepressant effects.
Biological Psychiatry Global Open Science
March 1, 2025
Noga Aviad, Oz Moskovich, Ophir Orenstein et al.
A machine learning algorithm classified electroencephalography (EEG) recordings from 26 experienced meditators as either a focused attention meditation state or a mind-wandering control state with 83% accuracy. The model identified 10 EEG features associated with increased power and coherence of high-frequency brain oscillations during meditation relative to mind-wandering. The findings help characterize the complex, systemic oscillatory activity underlying meditation states.
Biological Psychiatry Global Open Science
March 1, 2025
Lara M.c. Puhlmann, Pascal Vrtička, Roman Linz et al.
A randomized clinical trial with 332 healthy adults tested whether mindfulness- and meditation-based mental training can increase brain-derived neurotrophic factor (BDNF), a protein that supports hippocampal neuroplasticity, and whether cortisol reduction mediates this effect. Participants were assigned to one of three training cohorts (attention-based mindfulness, socio-affective skills, or socio-cognitive skills) or a passive control group. Training cohorts completed up to three 3-month modules. Combined training groups showed significant cumulative increases in serum BDNF after 3, 6, and 9 months relative to baseline (estimated increases: 1353, 1557, and 2276 pg/mL, respectively).
Biological Psychiatry Global Open Science
January 1, 2025
Perla Kaliman, María Jesús Álvarez-López, Asrar Lehodey et al.
Shorter telomeres are linked to a higher risk of cognitive decline and age-related diseases. An 18-month meditation training program in adults aged 65 and older did not significantly affect telomere length measures compared to a non-native language training or passive control group. Telomere length generally decreased over time across all groups. However, within the meditation group, greater class attendance and higher responsiveness to the intervention were associated with longer telomeres, and lower openness to experience correlated with fewer critically short telomeres. The findings suggest that while meditation did not show a main effect on telomere preservation, individual factors may influence outcomes.
Biological Psychiatry Global Open Science
November 1, 2024
Sébastien Czajko, Jelle Zorn, Loïc Daumail et al.
Long-term Buddhist practitioners show distinct, enduring patterns of large-scale brain functional connectivity that are present whether they are meditating or resting, indicating that meditation expertise produces trait-like neural changes. Comparing 28 expert meditators with 47 matched novices, a machine-learning classifier successfully decoded expertise from brain scans taken during both meditative and nonmeditative states. The experts' brains exhibited greater integration across multiple networks, including those involved in attention, emotion, body awareness, and cognitive control. This increased integration correlated with a stronger ability to create psychological distance from thoughts and emotions, suggesting that meditation cultivates an embodied cognition that persists beyond formal practice.
Biological Psychiatry Global Open Science
October 1, 2023
Ben Julian A Palanca, Charles R Conway, Thomas Zeffiro et al.
In healthy volunteers, a single 1-hour inhalation of 50% nitrous oxide produced changes in brain connectivity that lasted at least 24 hours. Using resting-state functional MRI, the study found increased global connectivity in the occipital cortex at 2 and 24 hours after inhalation, particularly between the visual network and the dorsal attention network. Weaker connectivity changes were observed between the visual cortex and frontoparietal and default mode networks. No significant connectivity changes followed inhalation of air/oxygen. These persistent cortical effects suggest nitrous oxide induces neurophysiological changes beyond its acute psychotropic effects.