Mescaline Alters Cerebellar Function, Global Connectivity, and Frequency-Selective Acoustic Gating: A BOLD fMRI Study in Awake Rats.
Neuroscience bulletin May 21, 2026 Noah Cavallaro, Priya Rai, David Akins et al.
Mescaline, a psychedelic used ceremonially for thousands of years, produces distinct brain effects that differ from LSD and psilocybin. In awake rats, mescaline suppressed BOLD signal in the cerebellum, suggesting it disconnects this region from forebrain areas. However, resting-state scans showed the cerebellum became hyperconnected to the hippocampus, thalamus, somatosensory cortex, and midbrain. Mescaline also eliminated normal brain responses to rewarding smells, indicating disrupted sensory processing. Acoustic startle tests revealed frequency-dependent effects: enhancement at 4 kHz (+27.6%) and 20 kHz (+27.3%), but impairment at 12 kHz (-16.4%). The cerebellum may act as a dysregulated sensory filter, flooding forebrain circuits with unprocessed information, potentially explaining psychedelic-induced perceptual changes.