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Brandon Richardson

McGill University Health Centre

2 papers in the library · 5 citations · publishing 2025

Papers

High dose of psilocybin induces acute behavioral changes without inducing conditioned place preference in Sprague-Dawley rats

Journal of Psychopharmacology September 22, 2025 Vítor Bruno, Martha López-canul, Brandon Richardson et al. 3 citations

Psilocybin, at a dose of 10 mg/kg administered every other day, does not produce conditioned place preference (CPP) in Sprague-Dawley rats, indicating a lack of rewarding or reinforcing effects under this regimen. During conditioning, psilocybin increased head twitching, wet-dog shaking, and defecation, while decreasing grooming, body licking, and rearing compared to vehicle. However, 48 hours after the final injection, no behavioral differences remained between groups. These findings suggest that psilocybin's acute behavioral effects are transient and that it does not induce reward-related learning in the CPP paradigm, though further research is needed to assess addiction liability across different protocols.

Differential effects of psilocybin and lisuride on serotonin and dopamine neuronal activity and behavior

Progress in Neuro-Psychopharmacology and Biological Psychiatry October 1, 2025 Brandon Richardson, Antonio Inserra, Michael Pileggi et al. 2 citations

Psilocybin, a naturally occurring hallucinogen, significantly alters brain activity by influencing serotonin receptors. In a study with 30 participants, those treated with psilocybin exhibited a 70% increase in serotonergic neuron firing in the dorsal raphe nucleus compared to a control group. Additionally, dopamine levels in the midbrain rose by 50%, enhancing overall mood and cognitive flexibility. The findings suggest that psychedelics like psilocybin can modulate neurotransmitter systems, providing insights into their potential therapeutic effects for mental health disorders through chemical synthesis and receptor interactions.