Nature
August 1, 2024
Joshua S. Siegel, Subha Subramanian, Demetrius Perry et al.
241 citations
A single high dose of psilocybin (25 mg) massively disrupts functional connectivity in the human brain, causing more than threefold greater change than methylphenidate (40 mg). These changes are driven by desynchronization across spatial scales, dissolving network distinctions by reducing correlations within and anticorrelations between networks. The strongest effects occur in the default mode network, which is connected to the anterior hippocampus and is thought to create the sense of space, time, and self. Individual differences in connectivity changes are strongly linked to the subjective psychedelic experience. A persistent decrease in connectivity between the anterior hippocampus and default mode network lasts for weeks, suggesting a neuroanatomical correlate of the therapeutic and proplasticity effects of psychedelics.
Journal of Neurological Sciences
January 1, 2022
Subha Subramanian, S. Haroutounian, B. Palanca et al.
58 citations
Ketamine, an anesthetic and NMDA receptor antagonist, is used to treat chronic pain and depression, conditions that often co-occur and may share neural pathways. Intravenous and intranasal ketamine are both effective for acute depressive episodes, with intravenous administration having higher bioavailability and providing better post-operative pain relief while reducing opioid use. Few studies have addressed ketamine's effects on concurrent depression and pain. Larger randomized controlled trials are needed to compare the safety and efficacy of intravenous versus intranasal ketamine, identify ideal target populations, and determine optimal dosing for treating both conditions.
medRxiv
August 24, 2023
Subha Subramanian, Demetrius Perry, Caterina Gratton et al.
14 citations
preprint
Psilocybin disrupts connectivity across cortical networks and subcortical structures, producing more than three-fold greater acute changes in functional networks than methylphenidate. These changes are driven by desynchronization of brain activity across spatial scales, strongest in the default mode network (DMN), which is connected to the anterior hippocampus and thought to create our sense of self. Performing a perceptual task reduces psilocybin-induced network changes, suggesting a neurobiological basis for grounding during psychedelic therapy. Psilocybin induces a persistent decrease in functional connectivity between the anterior hippocampus and cortex (and DMN in particular), lasting for weeks but normalizing after six months. This persistent suppression of hippocampal-DMN connectivity represents a candidate neuroanatomical and mechanistic correlate for psilocybin's pro-plasticity and anti-depressant effects.
Scientific Data
June 5, 2025
Subha Subramanian, Travis Rick Renau, Demetrius Perry et al.
4 citations
A psychedelic drug, psilocybin, and a comparison drug, methylphenidate, produce distinct acute and persistent changes in brain networks measurable with precision functional mapping, a technique that improves signal detection by repeatedly scanning individuals. Seven healthy adults underwent extensive baseline brain imaging, imaging shortly after drug intake, and follow-up scans for up to two weeks. Four participants repeated the psilocybin protocol months later. The dataset includes resting-state and task-based functional MRI, structural scans, and subjective experience reports. The authors release this resource to help researchers study how psilocybin and methylphenidate alter brain network organization over time.
Biological Psychiatry
April 29, 2024
Joshua S. Siegel, Subha Subramanian, Nico U.f. Dosenbach et al.
3 citations
No Summary
Asian Journal of Psychiatry
January 1, 2026
Hemant Bhargav, Urvakhsh Meherwan Mehta, Ashish Kumar et al.
Pranayama, the ancient yogic practice of breath control, acts as a natural method of neuromodulation by influencing autonomic functions, brainwave patterns, and neuroendocrine responses. Evidence from clinical, neuroimaging, and psychophysiological studies shows that techniques such as slow breathing, rapid breathing, and unilateral nostril breathing stimulate the vagus nerve, regulate the autonomic nervous system, and shift hemispheric brain dominance—mechanisms similar to contemporary approaches like transcranial magnetic stimulation and vagus nerve stimulation. Pranayama offers an accessible, self-directed alternative for managing stress, enhancing cognition, and promoting emotion regulation. Significant knowledge gaps remain, including the need for well-powered, randomized-controlled studies to understand durability of effects, optimal protocols, and mechanisms of action.
Mindfulness
October 5, 2021
Heather J. Brooks, H. Oughli, Lojine Y. Kamel et al.
Combining Mindfulness-Based Stress Reduction (MBSR) with transcranial direct current stimulation (tDCS) is feasible and safe for older adults with subjective memory complaints and symptoms of depression or anxiety. In a pilot double-blind randomized sham-controlled trial, 26 participants received either active or sham tDCS during MBSR sessions. The largest effect sizes for active versus sham tDCS were for everyday mindfulness and social functioning, though these were not statistically significant. At-home adherence and in-class attendance varied. The authors suggest tDCS may enhance MBSR by transferring meditative learning into everyday mindfulness.
October 23, 2018
B. Kadriu, Subha Subramanian, Z. Deng et al.
preprint
Major depressive disorder (MDD) is common, debilitating, and linked to suicide risk. Standard antidepressants can take weeks to work and have low remission rates, with about a third of patients not fully responding. Newer therapies targeting the glutamatergic system, such as ketamine, offer rapid antidepressant effects and high remission rates. This chapter reviews evidence for several novel therapeutics—ketamine, esketamine, nitrous oxide, scopolamine, GLYX-13, and buprenorphine—as well as interventional techniques like sleep deprivation. Ketamine and esketamine also rapidly reduce suicidal thoughts, making them useful in emergencies. Pivotal drug trials using rodents, neuroimaging, and electrophysiological studies are also reviewed to understand the neurocircuitry underlying MDD.