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
Full video version: [YouTube]
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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.
