Behind Closed Eyes: An Ayahuasca Experience
“As I closed my eyes, images – if they can be called such – began racing at an ever-increasing speed before me. Swirls of colors, shapes, forms, textures and sounds simply overpowered me to the point where I became immobile. Like many others before me, no doubt, I became somewhat frightened. What had I let myself in for? When I opened my eyes, the phantasmagoria of forms vanished, and I saw myself in the same room with the others”
Donald M. Topping’s description is very similar to the accounts many others have given. He brought up many questions on the vividness of visions produced after his very first ingestion of the hallucinogenic brew Ayahausca. What underlying brain mechanisms allow potentially healing, uplifting and fearful experiences to occur behind closed eyelids? That is what Draulio B. de Araujo and others sought out to find.
Ayahausca is a thick, brown potion served orally as a tea decoction made of a bush (Psychotria viridis), which is a rich source of N,N-dimethyltryptamine (DMT), and a liana (Banisteriopsis caapi) containing beta-carbolines (such as harmine, harmaline, and tetrahydroharmine). The mixture of these two plants allows for the inhibition, by the beta-carbolines, of monoamine oxidase (MAO) ultimately causing DMT to be psychoactive after ingested. Naturally, when DMT is orally ingested by itself, it is inactivated by MAO. Soon after ingestion, the levels of 5-HT rise to incredible amounts. The unnatural changes in brain chemicals as a result of Ayahuasca are believed to cause the powerful visual hallucinations that have been continuously reported.
Using functional Magnetic Resonance Imaging (fMRI), Arauji et. al., the Brain Institute at the Federal University of Rio Grande do Norte took in ten participates whom were all frequent Ayahuasca users and photographed their brains before and after an ingestion of 120-200 mL of Ayahuasca to see where activation in the brain takes place. A closed-eyes imagery task was completed for both stages. The imagery task included three conditions: viewing natural images (people, animals, or trees), mentally generating the previously seen images, and then viewing a scrambled version of the image presented in the first condition. The scrambled image served as a baseline. Psychiatric scales were also applied at intervals of 0, 40, 80, and 200 min after ingestion to detect symptoms of psychosis and mania.
Results would demonstrate an overall increase in the psychiatric scales after Ayahuasca intake, with a significant increase at 40 and 80 min. The mean time for DMT in the Ayahuasca mixture to reach its peak concentration, Tmax, is 90-120 minutes. This would also explain why an Ayahuasca experience can last for several hours. Results from the fMRI data showed significant activity in the occipital, temporal, and frontal cortical areas which are involved with vision, memory, and intention, respectively.
Moreover, the activity in the occipital areas (BA17, BA19, and BA7) was significant because the BOLD signal amplitude after intake increased during the imagery condition, but not during the natural image condition. It is also worth mentioning that the increased activity of the BA17 location in the occipital region, which works with the cuneus and lingual gyrus, corresponds to the peripheral visual field. This area may play a major role in why post-Ayahausca imagery is so intense even behind closed eyelids. Ayahuasca also induced activity in temporal areas in the parahippocampal cortex (BA30) and the retrosplenial cortex (BA37) during the imagery condition, which are areas that deal with the retrieval of episodic memories and the processing of contextual associations. In addition, frontopolar cortex (BA10) activity was also increased during the imagery condition perhaps because subjects intentionally create the images in their minds and interestingly enough, was the only area to produce a positive BOLD signal during the imagery condition before the intake and then potentiated after intake.
While my interest continues to grow about this psychotropic plant tea, I can rest assured that I know how my primary visual cortex activity can be intensified and like others be able to experience another dimension of reality behind closed eyes. Besides its original use in select South American religious ceremonies, Ayahuasca can be used for therapy. People like Donald M. Topping, after going through several sessions of Ayahuasca ingestion, left his oncologist’s office one day with his cancer activity indicator below normal. Many more have left with their symptoms of depression and anxiety miraculously gone, which can also be seen in another study by R.G. Santos et. al. where they suggest Ayahuasca can produce beneficial effects on mood and anxiety. Even after its many centuries of use there is still much to be learned about the neural basis of Ayahuasca’s potent psychological effects. Unraveling the mystery of Ayahuasca could potentially be utilized in the future as a readily available alternative medicine.
Effects of ayahuasca on psychometric measures of anxiety, panic-like and hopelessness in Santo Daime members – Journal of Ethnopharmacology
Ayahuasca and Cancer: One Man’s Experience – Maps.org