Psilocybin and Neuroplasticity: How the Brain Rewires Itself

How psilocybin promotes growth of new neural connections in the brain — what the rodent and human research shows, and the limits of what we currently know.

By The Microdose Movement · April 10, 2026

In one sentence: Psilocybin causes measurable growth of new connections between neurons in the cortex within 24 hours of a single dose, and the changes can persist for weeks.

When researchers talk about psilocybin’s potential to treat depression, anxiety, and trauma, the conversation almost always lands on one word: neuroplasticity. The brain’s ability to rewire itself is the bridge between the acute psychedelic experience and the lasting mood changes that some people report.

This page explains what neuroplasticity is, what the research has actually found about psilocybin’s effect on it, and what the field still does not understand.

What is neuroplasticity in plain language?

Neuroplasticity is the brain’s capacity to change its own wiring in response to experience. The connections between neurons — the synapses — can grow stronger, grow weaker, branch out, or be pruned away. This is not a special mode the brain enters occasionally. It is happening constantly, at varying rates, throughout life.

There are several types of neuroplasticity worth distinguishing:

Synaptic plasticity — changes in the strength of existing connections between neurons. This is the molecular basis of learning and memory.
Structural plasticity — physical growth or pruning of neuronal connections, including the formation of new dendritic spines (the small bumps where synapses form).
Neurogenesis — the creation of entirely new neurons. This happens in adults but only in specific brain regions, primarily the hippocampus.

When psychedelic researchers talk about neuroplasticity, they usually mean structural plasticity — the physical growth of new connections in the cortex.

What did the 2018 Ly study actually find?

The landmark paper in this field was published by Calvin Ly and colleagues in David Olson’s lab at UC Davis in 2018. The paper was titled “Psychedelics promote structural and functional neural plasticity,” and it appeared in Cell Reports.

The team gave classic psychedelics — including DMT, LSD, and psilocin — to neurons in culture and to live rodents. They found that within 24 hours of a single dose:

The number of dendritic spines on cortical neurons increased significantly
The complexity of dendritic branching expanded
New synapses formed
Functional connectivity between neurons increased

The effect was rapid, robust across multiple psychedelic compounds, and looked structurally similar to the effects produced by ketamine (a known fast-acting antidepressant). Olson’s lab coined the term psychoplastogen to describe compounds that produce this kind of rapid, lasting neural growth.

A 2021 follow-up study by Shao and colleagues at Yale used in vivo two-photon imaging to watch dendritic spines grow in real time in mouse frontal cortex after a single dose of psilocybin. The growth was visible within 24 hours and persisted for at least one month.

A 2024 paper in Nature by Vargas and colleagues showed that the new synaptic connections formed after psilocybin appeared to be functional, not just structural — they integrated into existing circuits and changed how the brain processed information.

How does this connect to mood and depression?

The leading hypothesis goes roughly like this: chronic stress and depression are associated with loss of dendritic spines and reduced synaptic density, particularly in the prefrontal cortex. Imaging and post-mortem studies have shown reduced neural complexity in depressed brains. Stress shrinks the connections.

Psilocybin appears to do the opposite. By rapidly promoting dendritic spine growth and new synapse formation, it may temporarily reverse some of the structural changes depression has caused. The new connections create a window of increased plasticity in which the brain is unusually capable of forming new patterns — including new emotional patterns, new associations, and new ways of relating to old memories.

This is why integration matters so much in psychedelic-assisted therapy. The drug opens the window. What you do during that window determines what gets wired in.

Is this also why psilocybin’s effects last beyond the acute experience?

Probably yes, though the link is not yet fully proven.

The acute psychedelic experience lasts a few hours. The plasma concentration of psilocin drops to negligible levels within a day. But people in clinical trials often report mood improvements lasting weeks or months after a single dose. That gap — between how briefly the molecule is present and how long the mood change lasts — is one of the central puzzles of the field.

The neuroplasticity story is the leading explanation. The acute experience may produce structural changes that outlast the molecule itself, leaving the brain in a slightly different configuration for weeks afterward. The “afterglow” people describe is consistent with a brain operating in a slightly more plastic, slightly more flexible state.

A 2022 study by Singleton and colleagues at the Centre for Psychedelic Research showed that brain network flexibility — measured by how easily the brain switched between functional configurations — remained elevated for three weeks after a single psilocybin dose in depressed patients. The patients who showed the largest network flexibility increases also showed the largest reductions in depression scores.

Does microdosing produce the same neuroplastic effects?

This is the honest cliffhanger of the field. Most of the dramatic neuroplasticity research has been done with full psychedelic doses. Whether microdoses — taken at sub-perceptual levels — produce the same kind of dendritic growth is an open question.

A few small studies suggest there is some effect at lower doses. Catlow and colleagues at the University of South Florida published a 2013 paper showing that low-dose psilocybin promoted hippocampal neurogenesis and accelerated extinction of fear conditioning in mice. The doses they used were small but not strictly sub-perceptual by human standards.

The strongest claim that can currently be made: microdoses likely produce some plasticity effect, the effect is probably smaller than what full doses produce, and the cumulative effect of repeated microdoses over weeks may add up to something meaningful even if any single dose is modest.

This is one of the most active areas of microdosing research right now and the picture will get clearer in the next few years.

What we still do not know

Whether microdoses produce structural plasticity changes equivalent to or proportionally smaller than full doses.
How long psilocybin-induced plasticity changes actually last in humans (most measurements have been done in rodents).
Whether the new synaptic connections formed under psilocybin are stable contributions to function or whether they get pruned back over weeks.
The role of BDNF (brain-derived neurotrophic factor) in mediating these effects, which is suspected but not fully proven.
Whether intentional integration practices during the plastic window measurably improve outcomes versus passive recovery.

Frequently Asked Questions

Does psilocybin actually grow new brain cells?

Mostly no — it does not appear to produce new neurons in adults. What it does produce is new connections between existing neurons: dendritic spines, synapses, and branching structures. There is some weak evidence for hippocampal neurogenesis at low doses in rodents, but the main effect is structural plasticity, not neurogenesis.

How long does psilocybin neuroplasticity last?

In rodent studies, dendritic spine increases have been measured for at least one month after a single dose. In human studies, network flexibility changes have been measured for up to three weeks. Whether the changes are permanent or get reabsorbed over longer periods is an open question.

Is psilocybin a psychoplastogen?

Yes — the term “psychoplastogen” was coined specifically to describe compounds like psilocybin and LSD that produce rapid, lasting neural plasticity. Other psychoplastogens include ketamine and certain non-psychedelic compounds in development.

Does microdosing build new connections in the brain?

Probably, but the effect is likely smaller than full doses. The research on microdose-specific plasticity is still in early stages and most of what we know is extrapolated from full-dose studies.

What is the role of BDNF in psilocybin neuroplasticity?

BDNF is a protein that supports neuron survival and growth. Some studies suggest psilocybin increases BDNF expression in cortical neurons, and that the structural plasticity effects of psilocybin may be partly mediated by BDNF signaling. The full mechanism is still being mapped.

Sources and Further Reading

Ly, C., et al. (2018). “Psychedelics promote structural and functional neural plasticity.” Cell Reports, 23(11), 3170–3182. Read paper
Shao, L. X., et al. (2021). “Psilocybin induces rapid and persistent growth of dendritic spines in frontal cortex in vivo.” Neuron, 109(16), 2535–2544.
Vargas, M. V., et al. (2024). “Psychedelics promote neuroplasticity through the activation of intracellular 5-HT2A receptors.” Nature, 627, 397–406. Read paper
Catlow, B. J., et al. (2013). “Effects of psilocybin on hippocampal neurogenesis and extinction of trace fear conditioning.” Experimental Brain Research, 228(4), 481–491.
Singleton, S. P., et al. (2022). “Receptor-informed network control theory links LSD and psilocybin to a flattening of the brain’s control energy landscape.” Nature Communications, 13, 5812.
Olson, D. E. (2018). “Psychoplastogens: a promising class of plasticity-promoting neurotherapeutics.” Journal of Experimental Neuroscience, 12, 1179069518800508.

This page is for educational purposes. Nothing here is medical advice. The Microdose Movement is an educational community, not a clinical provider.