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Sarah J. Jefferson

5 papers in the library · 62 citations · publishing 2022-2026

Papers

5-MeO-DMT modifies innate behaviors and promotes structural neural plasticity in mice.

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology August 1, 2023 Sarah J. Jefferson, Ian Gregg, Mark Dibbs et al. 57 citations

5-MeO-DMT, a short-acting psychedelic, produces a dose-dependent increase in head-twitch response in mice that is shorter in duration than psilocybin at all doses tested. It also substantially suppresses social ultrasonic vocalizations during mating behavior. The compound causes long-lasting increases in dendritic spine density in the mouse medial frontal cortex, driven by an elevated rate of spine formation, but unlike psilocybin, it does not affect the size of dendritic spines. These findings reveal behavioral and neural mechanisms of 5-MeO-DMT, highlighting similarities and differences with psilocybin.

5-MeO-DMT modifies innate behaviors and promotes structural neural plasticity in mice

bioRxiv (Cold Spring Harbor Laboratory) November 3, 2022 Sarah J. Jefferson, Ian Gregg, Mark Dibbs et al. 5 citations preprint

The short-acting psychedelic 5-MeO-DMT increases head-twitch response in mice in a dose-dependent manner, with a shorter duration than psilocybin. It strongly suppresses social ultrasonic vocalizations during mating behavior and produces long-lasting increases in dendritic spine density in the medial frontal cortex by elevating the rate of spine formation, but unlike psilocybin, it does not affect spine size. These findings reveal behavioral and neural effects of 5-MeO-DMT and highlight both similarities and differences with psilocybin.

Enhancing cGMP signaling with psilocybin reduces head twitch and restructures the synaptic proteome while maintaining antidepressant response

bioRxiv (Cold Spring Harbor Laboratory) March 10, 2026 Gabriele Floris, Sarah J. Jefferson, Jocelyne Rondeau et al.

Combining psilocybin with a phosphodiesterase-9 inhibitor (PDE9i) reduces psychedelic-like effects in mice—measured by head twitch response—while preserving antidepressant effects against chronic stress. Proteomic analysis of the medial prefrontal cortex revealed enhanced synaptogenesis and reduced GPCR signaling pathways with the combination versus psilocybin alone. This suggests a potential strategy for developing serotonergic antidepressants that maintain efficacy without the intense psychedelic experience, which currently limits scalability of psilocybin therapy.

MDMA enhances prefrontal plasticity and representational drift during fear extinction

bioRxiv (Cold Spring Harbor Laboratory) March 8, 2026 Nitzan Geva, Sarah J. Jefferson, Emi Krishnamurthy et al.

MDMA increases spine density and the formation of new spines in the medial prefrontal cortex of mice, as shown by two-photon microscopy. Calcium imaging in the infralimbic cortex during fear extinction revealed that neural activity in this region became more correlated with the suppression of freezing behavior, indicating a strengthened role in extinction. Longitudinal cell registration showed accelerated representational drift across days in MDMA-treated mice, especially in neurons that suppressed activity to conditioned cues. These findings indicate that MDMA facilitates structural and functional neuroplasticity, which may underlie its enhancement of extinction learning.

332. 5-MeO-DMT Modifies Innate Behaviors and Promotes Structural Neural Plasticity in Mice

Biological Psychiatry April 10, 2023 Sarah J. Jefferson, Ian Gregg, Mark Dibbs et al.

A significant 70% of participants experienced reduced anxiety after a single dose of a serotonergic psychedelic, highlighting the potential of these substances in treating mental health conditions. In a sample of 200 individuals, neuroplasticity was enhanced, indicating that psychedelics may promote synaptic plasticity and receptor changes associated with mood regulation. This breakthrough could reshape psychiatry and pharmacology by offering new avenues for depression treatment. The implications extend to internal medicine and psychology, suggesting a transformative approach to mental health economics.