Psilocybin induces rapid and persistent growth of dendritic spines in frontal cortex in vivo
Delagarza, K., Gregg, I., Kwan, A. C., Liao, C., Savalia, N., Shao, L-X,
This cell study shows that brain cells, specifically the layer five pyramidal neurons in mice, grew by 10% after the introduction of psilocybin. The effects were still present 30 days later, providing more evidence for brain plasticity as an underlying mechanism of psychedelic-assisted therapies' long-lasting effects.
Abstract
Psilocybin is a serotonergic psychedelic with untapped therapeutic potential. There are hints that the use of psychedelics can produce neural adaptations, although the extent and timescale of the impact in a mammalian brain are unknown. In this study, we used chronic two-photon microscopy to image longitudinally the apical dendritic spines of layer 5 pyramidal neurons in the mouse medial frontal cortex. We found that a single dose of psilocybin led to ∼10% increases in spine size and density, driven by an elevated spine formation rate. The structural remodeling occurred quickly within 24 h and was persistent 1 month later. Psilocybin also ameliorated stress-related behavioral deficit and elevated excitatory neurotransmission. Overall, the results demonstrate that psilocybin-evoked synaptic rewiring in the cortex is fast and enduring, potentially providing a structural trace for long-term integration of experiences and lasting beneficial actions.