Chronic social isolation in marmosets leads to significant shrinkage of neurons in the striatum, a brain region that integrates emotion, motivation, and movement. Ayahuasca, a psychoactive plant-based brew, given before and during isolation, prevented this neuronal volume loss. The caudate and putamen of socially isolated animals treated with ayahuasca showed neuron sizes comparable to those of family-housed controls, while untreated isolated animals had markedly smaller neurons. The findings suggest ayahuasca may act as a prophylactic buffer against stress-induced structural brain changes.
Individuals with recurrent isolated sleep paralysis (RISP) show notable brain changes, including an increased cerebellar vermis height and a larger midbrain-pons junction. In a study of 20 participants (10 with RISP, average age 24.7; 10 controls, average age 26.3), MRI scans revealed these significant morphological differences, suggesting an over-compensatory mechanism in the brain's regulatory pathways. Despite these findings, no major variations in overall sleep structure were observed between the two groups, indicating that RISP may involve specific brain adaptations rather than broader sleep disturbances.