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Wide release: February 9, 2026. Not medical advice.

TOPICS DISCUSSED:

* Cerebral cortex structure: Described as a six-layered structure with pyramidal neurons and inhibitory interneurons; information flows between layers and regions to process sensory input and enable complex behaviors.

* Claustrum anatomy & connectivity: A sheet-like subcortical structure embedded in white matter, bidirectionally connected to cortical areas, especially prefrontal regions in rodents, with broader connections in primates and humans suggesting an integrative role.

* Claustrum function in cognition: Experiments show claustrum activation during task switches from easy to demanding modes, synchronizing cortical networks via inhibition and rebound excitation, potentially enabling flexible behavior.

* Mouse models in neuroscience: Mice are used for genetic tractability to manipulate and monitor specific circuits, revealing claustrum’s role in vigilance tasks but not simple ones.

* Alcohol’s effects on brain circuits: Chronic alcohol promotes inflexible behaviors by altering striatal interneurons and inhibitory inputs, leading to compulsive drinking despite aversive consequences.

* Psychedelics & brain networks: Psilocybin disrupts default mode and other networks, inhibits claustrum via serotonin 1B receptors, with effects persisting 24 hours, possibly contributing to therapeutic benefits.

* Evolution of claustrum: Connectivity expands from rodents to humans, shifting from cognitive-specific to broader network control, including anti-correlated states like default mode versus task-engaged.

* Integration of claustrum & basal ganglia: Claustrum funnels prefrontal signals to basal ganglia for action selection; alcohol may impair this, exacerbating inflexibility in addiction.

ABOUT THE GUEST: Brian Mathur, PhD is a professor in the Department of Pharmacology and Physiology at the University of Maryland School of Medicine, where he leads a neuroscience lab studying brain circuits underlying flexible and inflexible behaviors using mouse models, with a focus on alcohol use disorder.

RELATED EPISODE:

* M&M 226 | Psychedelics & Cerebral Cortex: Neuroplasticity, Psilocybin, Ketamine | Alex Kwan

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PRACTICAL TAKEAWAYS:

* Moderate alcohol consumption can impair decision-making and coordination by affecting prefrontal cortex and cerebellum, so limit intake during tasks requiring focus.

* Chronic heavy drinking may lock in maladaptive habits; seeking therapy or support can help regain behavioral flexibility.

* Psychedelics like psilocybin may reset rigid thought patterns in conditions like depression, but use under medical supervision for potential long-term benefits.

SUBSCRIBER CONTENT BELOW: Reference paper + episode transcript.