Researchers investigated whether psilocybin, a compound from certain mushrooms, could be safely used to treat memory problems in older adults with mild cognitive impairment. In this early-stage study, participants received either psilocybin or a placebo while researchers used brain imaging to measure changes in synaptic connections. The preliminary results suggest psilocybin was well-tolerated with manageable side effects like dizziness, and participants were able to complete the study without serious problems.