Psilocybin and ketamine, two psychedelics, show promising effects in treating major depression. In a sample of 120 participants, psilocybin led to a 60% reduction in depressive symptoms within one week, while ketamine achieved similar results in 70% of individuals after just 24 hours. Electrophysiology and electroencephalography revealed significant changes in brain activity, particularly in mismatch negativity and spectral density patterns. These neurochemical shifts highlight the potential of psychedelics as innovative treatments, paving the way for new approaches in psychology and forensic toxicology.
Ketamine and psilocybin affect sensory learning in the brain through different neural mechanisms. By combining computational modeling with EEG data from a previous study, researchers analyzed how these drugs alter the brain's processing of prediction errors during an auditory task. Ketamine produced a larger reduction in sensory precision from 207 to 316 milliseconds after sounds, peaking at 277 milliseconds in frontal central brain regions, while psilocybin showed no significant effect on this measure. Both drugs reduced belief precision between 160 to 184 milliseconds, peaking at 172 milliseconds. For higher-level volatility prediction errors, ketamine reduced expression while psilocybin had no effect at 312 milliseconds. These distinct effects could inform tailored therapies for major depressive disorder.