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Leanne M Williams

6 papers in the library · 84 citations · publishing 2021-2026

Papers

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Psychedelics disrupt hierarchical cortical propagations in the default mode network of humans and mice.

Proceedings of the National Academy of Sciences of the United States of America June 16, 2026 Adam R Pines, Xue Zhang, John Kochalka et al.

Psychedelic drugs are poised to become mainstream treatments, yet we lack a circuit-level account of how they reshape brain activity. Emerging evidence suggests that multiple psychedelic compounds modulate activity in the brain's default mode network (DMN), often interpreted as either increased or decreased bottom-up hierarchical processing. Most imaging studies, however, quantify activity as...

Negative Affect Circuit Subtypes and Neural, Behavioral, and Affective Responses to MDMA: A Randomized Clinical Trial.

JAMA Network Open April 1, 2025 Xue Zhang, Laura M Hack, Claire Bertrand et al. 10 citations

Rapidly acting therapeutics like 3,4-methylenedioxymethamphetamine (MDMA) are promising treatments for disorders such as posttraumatic stress disorder (PTSD). However, understanding who benefits most and the underlying neural mechanisms remains a critical gap. Stratifying individuals by neural circuit profiles could help differentiate neural, behavioral, and affective responses to MDMA,...

Oral ketamine effects on dynamics of functional network connectivity in patients treated for chronic suicidality.

European Archives of Psychiatry and Clinical Neuroscience May 21, 2024 Zack Y Shan, Adem T. Can, Abdalla Z Mohamed et al. 3 citations

The underlying brain mechanisms of ketamine in treating chronic suicidality and the characteristics of patients who will benefit from ketamine treatment remain unclear. To address these gaps, we investigated temporal variations of brain functional synchronisation in patients with suicidality treated with ketamine in a 6-week open-label oral ketamine trial. The trial's primary endpoint was the...

UNRAVELing the synergistic effects of psilocybin and environment on brain-wide immediate early gene expression in mice.

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology November 1, 2023 Daniel Ryskamp Rijsketic, Austen B Casey, Daniel A. N. Barbosa et al. 49 citations

The effects of context on the subjective experience of serotonergic psychedelics have not been fully examined in human neuroimaging studies, partly due to limitations of the imaging environment. Here, we administered saline or psilocybin to mice in their home cage or an enriched environment, immunofluorescently-labeled brain-wide c-Fos, and imaged iDISCO+ cleared tissue with light sheet...

Ketamine’s acute effects on negative brain states are mediated through distinct altered states of consciousness in humans

Nature Communications October 19, 2023 Laura M Hack, Xue Zhang, Boris D. Heifets et al. 20 citations

Ketamine commonly and rapidly induces dissociative and other altered states of consciousness (ASCs) in humans. However, the neural mechanisms that contribute to these experiences remain unknown. We used functional neuroimaging to engage key regions of the brain’s affective circuits during acute ketamine-induced ASCs within a randomized, multi-modal, placebo-controlled design examining placebo,...

Acute Ketamine Modulated Functional Brain Coupling and Dissociative and Affective States in Human Subjects: Interim Analyses

bioRxiv Preprint Server September 20, 2021 Laura M Hack, Katherine G. Warthen, Xue Zhang et al. 2 citations preprint

Ketamine is a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) glutamate receptor that is both a drug of abuse and an FDA-approved anesthetic used off-label for treatment-resistant depression. Despite its growing clinical use for depression and pain, the relationships between the acute dissociative and affective effects of ketamine that contribute to its abuse liability and...