Seeing with the eyes shut: Neural basis of enhanced imagery following ayahuasca ingestion

Abstract

The hallucinogenic brew Ayahuasca, a rich source of serotonergic agonists and reuptake inhibitors, has been used for ages by Amazonian populations during religious ceremonies. Among all perceptual changes induced by Ayahuasca, the most remarkable are vivid "seeings." During such seeings, users report potent imagery. Using functional magnetic resonance imaging during a closed-eyes imagery task, we found that Ayahuasca produces a robust increase in the activation of several occipital, temporal, and frontal areas. In the primary visual area, the effect was comparable in magnitude to the activation levels of natural image with the eyes open. Importantly, this effect was specifically correlated with the occurrence of individual perceptual changes measured by psychiatric scales. The activity of cortical areas BA30 and BA37, known to be involved with episodic memory and the processing of contextual associations, was also potentiated by Ayahuasca intake during imagery. Finally, we detected a positive modulation by Ayahuasca of BA 10, a frontal area involved with intentional prospective imagination, working memory and the processing of information from internal sources. Therefore, our results indicate that Ayahuasca seeings stem from the activation of an extensive network generally involved with vision, memory, and intention. By boosting the intensity of recalled images to the same level of natural image, Ayahuasca lends a status of reality to inner experiences. It is therefore understandable why Ayahuasca was culturally selected over many centuries by rain forest shamans to facilitate mystical revelations of visual nature.

Psychedelics

“…A connectivity analysis revealed that ayahuasca strongly altered fronto-occipital relationships, leading to marked changes in the timing of events across several brain regions. de Araujo et al (2012) speculate that the robust visions induced by ayahuasca may even be initiated in the primary visual cortex.…”

“…de Araujo et al (2012) investigated the neural basis of imagery induced by the psychedelic Amazonian brew ayahuasca. They studied 10 regular ayahuasca users who participated in two fMRI sessions.…”

Ayahuasca: what mental health professionals need to know

“…These brain areas are involved in the modulation of emotions, internal feelings and sensations, perception and self-awareness. An fMRI study using an imagery task showed that ayahuasca not only increased activation of the parahippocampal and frontopolar cortices, but also of the cuneus and lingual gyrus and retrosplenial cortex 20 . Interestingly, during the imagery task ayahuasca increased activation of the primary visual area in a manner similar to the activation levels of seeing a natural image with the eyes open.…”

Nonlocality and the Shamanic State of Consciousness

“…It has been emphasized that the size of the neuroaxonal network makes it ineligible for maintaining this kind of interaction; rather, we should be looking for a subcellular system possibly at the level of the lipoprotein membrane structures-or else (e.g., cytosol) at the bottom of 4 'Perceptual-cognitive' in our use strictly refers to a sensory input driven cognitive processing. Visions can be sensed as profoundly perceptual while lacking the activation of the sensory organs (de Araujo et al, 2012). As we will point out later, veridical information accessed during visionary experiences emerges via the "nonlocalintuitive" channel.…”