Investigating the Persisting Effects of a Single Dose of Psilocybin on Structural Plasticity in Healthy Older Adults

Participants in this study will undergo a series of non-invasive tests and activities designed to understand how a single dose of psilocybin might influence cognition and emotional well-being in healthy older adults. After providing written informed consent, eligible participants, aged between 60 and 85, will be randomly assigned to receive a dose of psilocybin ranging from a microdose to a moderate-to-high dose. Anatomical magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI) will be used to assess changes in brain structure, while functional magnetic resonance imaging (fMRI) will be used to quantify changes in functional brain activity. The investigators will use cognitive exams, perceptual tasks, brain imaging, peripheral psychophysiology, and surveys to investigate the persisting effects of psilocybin on cognition, predictive coding, and affect in healthy older adults (60-85 years old). The investigators will measure changes in these measures by comparing baseline to one-week and one-month post-treatment. Participants will be randomly assigned to receive a dose of psilocybin in a range from microdose to moderate-to-high dose (1-30 milligrams). Anatomical magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI) will be used to assess changes in brain structure, while functional magnetic resonance imaging (fMRI) will be used to quantify changes in functional brain activity. The investigators will assess whether changes in these brain measures underlie observed changes in cognition, predictive coding and affect.