Summary: New research indicates that psychedelic drugs may act by strengthening specific brain connections involved in memory and cognition. Under psychedelic exposure, neurons in the claustrum — a region rich in receptors that respond to psychedelics — showed increased, persistent communication with the anterior cingulate cortex, a cortical area linked to mood regulation and psychiatric disorders.
This enhanced connectivity was not observed under normal conditions, suggesting that psychedelics can uniquely promote synaptic plasticity within targeted neural circuits. These findings help explain why psychedelic experiences are often intensely memorable and may underlie lasting therapeutic benefits observed in clinical settings.
Key Facts
- Target Region: Psychedelics preferentially influence the claustrum, a subcortical hub with a high density of serotonin 2 (5-HT2) receptors.
- Memory Encoding: When animals were exposed to psychedelics, connections between claustrum neurons and the anterior cingulate cortex were strengthened, a change that could encode vivid, persistent memories.
- Therapeutic Mechanism: This selective rewiring of claustro-cortical pathways may help explain why a single psychedelic session can produce lasting improvements in conditions such as depression, PTSD, and anxiety.
Source: SfN
Background: As evidence mounts about their therapeutic potential, psychedelic compounds are becoming less controversial within psychiatric research. Scientists are now focused on uncovering the neural mechanisms that might explain rapid and durable clinical improvements after psychedelic-assisted treatments.
In a recent paper published in eNeuro, a team led by Pavel Ortinski at the University of Kentucky examined how psychedelics affect the claustrum. Using male rats, the researchers investigated how psychedelics alter the function and plasticity of claustrum neurons that project to the anterior cingulate cortex (ACC), a cortical region implicated in mood regulation and psychiatric disorders.
The team found that activation of claustrum neurons that send signals to the ACC produced a persistent strengthening of the synaptic inputs onto those claustrum cells, but only when the animals were exposed to a psychedelic compound. In contrast, the same pattern of activation under baseline, non-psychedelic conditions did not trigger this long-term strengthening.
According to Ortinski, this observation supports the idea that the vivid, memorable nature of psychedelic experiences may be central to their therapeutic effects. He explains that neurons encode memories by strengthening their connections with one another; therefore, a drug-induced change in synaptic plasticity within claustro-cortical circuits could help lock in emotionally salient experiences that facilitate psychological change.
Ortinski and colleagues plan to continue probing whether this plasticity mechanism directly contributes to clinical improvements in psychiatric symptoms, and how long those circuit changes persist after drug exposure.
Key Questions Answered:
A: Current evidence suggests psychedelics can strengthen communication between brain regions that handle memory and emotion, potentially stabilizing new, healthier neural pathways that support recovery.
A: The claustrum appears to act as a coordination hub. Under psychedelic influence, it increases its output to the anterior cingulate cortex, amplifying activity patterns that are central to forming and storing emotionally significant memories.
A: Psychedelics may enhance the brain’s capacity for forming strong memory traces, making emotionally charged or transformative experiences more likely to be encoded and retained.
About this psychopharmacology research news
Author: SfN Media
Source: SfN
Contact: SfN Media – SfN
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Original Research: Closed access.
“Psychedelics Reverse the Polarity of Long-Term Synaptic Plasticity in Cortical-Projecting Claustrum Neurons” by Pavel Ortinski et al. eNeuro
Abstract
Psychedelics Reverse the Polarity of Long-Term Synaptic Plasticity in Cortical-Projecting Claustrum Neurons
Interest in psychedelic drugs has surged because of their potential to treat psychiatric conditions such as depression, anxiety, and substance use disorders. The claustrum (CLA), a thin, highly connected brain region that communicates extensively with frontal cortices, contains a dense population of serotonin 2 (5-HT2) receptors — the molecular targets of many psychedelic compounds.
Because some psychedelic therapies achieve notable benefits after a single session, researchers have hypothesized that these drugs might induce rapid and lasting neuroplastic changes in brain areas that underlie psychiatric symptoms, including the anterior cingulate cortex (ACC). Until now, however, the effects of psychedelics on synaptic plasticity within serotonin receptor–rich regions like the claustrum have been largely unexplored.
Using an experimental approach that paired presynaptic stimulation with postsynaptic action potentials in a subpopulation of claustrum neurons projecting to the ACC in male rats, the authors show that the psychedelic DOI can reverse the expected polarity of synaptic plasticity. Specifically, DOI converted responses that would normally lead to long-term depression (LTD) into long-term potentiation (LTP) at synapses activated by local electrical stimulation. The study also documents DOI-induced changes in intrinsic electrophysiological properties and action potential dynamics of CLA-ACC neurons.
Taken together, these results support the view that psychedelics promote rapid and persistent synaptic plasticity and reinforce the idea that claustro-cortical circuits are particularly sensitive to psychedelic drug action, offering a plausible neural substrate for the profound and often therapeutic experiences reported in clinical and experimental settings.