In brief
- A Brazilian team administered ayahuasca to rats during fear memory reconsolidation and observed reduced freezing behavior the following day.
- The effect was accompanied by an increase in dendritic spines in the dorsal hippocampus and prelimbic cortex, but not by increased neurogenesis in the dentate gyrus.
- This is a study on male rodents; it serves to understand mechanisms and does not allow for conclusions regarding its use in people with trauma.
Ayahuasca, the Amazonian decoction containing N,N-dimethyltryptamine (DMT), is once again under the microscope in the field of trauma. An article published in Molecular Neurobiology on October 12, 2026, describes changes in two regions of the rat brain when ayahuasca is administered while a fear memory is being rewritten.
What is reconsolidation and why it matters
Every time a memory is retrieved, it remains in a fragile state for a period and can be stored again with modifications. This window is called reconsolidation, and it is a classic target for research into post-traumatic stress disorder (PTSD): if one intervenes at that moment, it may be possible to attenuate the emotional weight of the memory.
The same group had already shown in previous work that ayahuasca reduces the expression of fear by interfering with this process. This time, they asked what happens at the structural level in neurons. Their hypothesis was that there would be plasticity changes in the dorsal hippocampus and the prelimbic cortex, two areas involved in context memory and fear regulation.
The design and results
The researchers used adult male Wistar rats, which learned to associate a context with an aversive stimulus. Afterward, they received 60 mg/kg of ayahuasca or water as a control via oral gavage, either 20 minutes before or 3 hours after retrieving the memory. To test the effect on reconsolidation, they re-exposed the animals to the context 24 hours later: those treated with ayahuasca showed a significant reduction in freezing behavior.
Twenty-four hours after treatment, they analyzed the neuronal structure using Golgi-Cox staining. They found a higher density of dendritic spines in the CA1, CA3, and dentate gyrus regions of the dorsal hippocampus, as well as in the prelimbic cortex. In the latter, moreover, the branching and length of the dendrites varied depending on when the ayahuasca was administered. Ten days later, they measured neurogenesis with doublecortin in the dentate gyrus and saw no differences.
The authors conclude that what is associated with the effect on reconsolidation is rapid synaptic remodeling, rather than the birth of new neurons in the adult hippocampus.
What it implies
The work fits with the line of research that positions synaptic plasticity as one of the central mechanisms of classic psychedelics. It provides a concrete finding: in this model, more dendritic spines without changes in neurogenesis. It is advisable to read it with its limitations in mind. This involves male rats, a single dose, and a behavioral measure in a laboratory context; the published summary does not allow for conclusions about effects in humans, nor about what happens in people with PTSD, nor about the exact role DMT plays compared to the other compounds in the brew.
Nor can the 60 mg/kg dose be translated from a rat to a ceremony or a clinical trial. What this type of study does is refine the questions that must later be answered by trials in people, which are still in very early stages today. If you want a general framework on this plant and its main alkaloid, you can consult our Ayahuasca and DMT guide, and the broader landscape of clinical research is in psychedelic science and therapy.
Source
- Daneluz, D. M., dos Santos, A. S., de Melo, S. R., de Oliveira, R. M. W. and Stern, C. A. J. Ayahuasca Impairs Fear Memory Reconsolidation and Promotes Rapid Structural Plasticity in the Hippocampus and Prelimbic Cortex. Molecular Neurobiology, October 12, 2026.
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
