Scientists identify key brain mechanism behind ayahuasca’s ability to reduce PTSD symptoms

Ayahuasca-based treatment is linked to improved fear extinction in PTSD-like conditions, with effects traced to brain plasticity mechanisms in the prefrontal cortex. In rodent experiments using trauma-like fear learning, ayahuasca reduced freezing behavior not only during extinction but also in a neutral context, indicating less fear generalization. The study used oral ayahuasca containing DMT and harmine, and administered a low DMT dose aimed at enhancing extinction without major locomotor or anxiety changes. Mechanistically, the infralimbic cortex appears to be a critical site of action. Blocking brain-derived neurotrophic factor (BDNF) or inhibiting its receptor TrkB in this region eliminated ayahuasca’s ability to facilitate fear extinction. Results also suggested sex-dependent differences in how fear generalization is reduced, motivating further work on personalized approaches.