Ayahuasca modulation of traumatic-like fear memories requires infralimbic cortex BDNF-dependent mechanisms in rats.

Ayahuasca, a brew containing the psychedelic DMT, helps rodents overcome persistent and generalized fear memories by boosting brain-derived neurotrophic factor (BDNF) signaling in the infralimbic (IL) region of the medial prefrontal cortex. In rats exposed to stress or high-intensity fear conditioning, repeated ayahuasca (0.3 mg/kg DMT) enhanced extinction learning and its retention, and reduced fear generalization. These effects were blocked by infusing an anti-BDNF antibody or a TrkB receptor antagonist into the IL cortex. The reduction in fear generalization depended on BDNF in females but not males. The findings suggest psychedelics may aid in treating difficult-to-extinguish trauma memories, such as those in PTSD.

Study at a glance

Abstract

Rodent studies have shown that psychedelic drugs can enhance fear extinction. However, investigations to date have relied on normative aversive conditioning procedures, which limit their relevance to trauma-related memories, as these tend to be overgeneralized and resistant to extinction. Fear extinction depends on activity and plasticity within the infralimbic (IL) region of the medial prefrontal cortex and is regulated by brain-derived neurotrophic factor (BDNF). Ayahuasca (AYA), a brew containing the serotonergic psychedelic N,N-dimethyltryptamine (DMT), facilitates fear extinction in rodents and increases BDNF levels/signaling. Here, we investigated whether AYA attenuates extinction deficits and generalized fear induced by preconditioning restraint stress or high-intensity contextual fear conditioning, and whether these effects depend on BDNF-TrkB receptor signaling in the IL cortex. Adult male and female rats underwent the protocols above and received oral AYA one hour before each of the two extinction sessions conducted on consecutive days. Repeated administration of AYA containing 0.3 mg/kg of DMT enhanced extinction learning and its retention, effects that were abolished by bilateral intra-IL cortex infusion of an anti-BDNF antibody or the TrkB receptor antagonist ANA-12. AYA treatment also reduced fear generalization, an action that was BDNF-dependent in the IL cortex of females but not males. Overall, these findings indicate that AYA can modulate maladaptive fear memories through cortical mechanisms involving BDNF signaling, highlighting the potential of psychedelics as enhancers for extinguishing difficult-to-treat memories like those underlying post-traumatic stress disorder.