Long-term use was associated with thinning of the posterior cingulate cortex , thickening of the anterior cingulate cortex , and decreased neocortical 5-HT2A receptor binding .
Despite the high method ological heterogeneity and the small sample sizes , the results suggest that hallucinogens increase introspection and positive mood by modulating brain activity in the fronto-temporo-parieto-occipital cortex
Serotonergic hallucinogens produce alterations of perceptions , mood , and cognition , and have anxiolytic , antidepressant , and antiaddictive properties .
These drugs act as agonists of frontocortical 5-HT2A receptors , but the neural basis of their effects are not well understood .
Thus , we conducted a systematic review of neuroimaging studies analyzing the effects of serotonergic hallucinogens in man .
Seeing with the eyes shut: neural basis of enhanced imagery following Ayahuasca ingestion.
The hallucinogenic brew Ayahuasca , a rich source of serotonergic agonists and reuptake inhibitors , has been used for ages by Amazonian population s 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 context ual 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 prospect i ve 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 underst and able why Ayahuasca was culturally selected over many centuries by rain forest shamans to facilitate mystical revelations of visual nature
Long-term use was associated with thinning of the posterior cingulate cortex , thickening of the anterior cingulate cortex , and decreased neocortical 5-HT2A receptor binding .
Despite the high method ological heterogeneity and the small sample sizes , the results suggest that hallucinogens increase introspection and positive mood by modulating brain activity in the fronto-temporo-parieto-occipital cortex
Serotonergic hallucinogens produce alterations of perceptions , mood , and cognition , and have anxiolytic , antidepressant , and antiaddictive properties .
These drugs act as agonists of frontocortical 5-HT2A receptors , but the neural basis of their effects are not well understood .
Thus , we conducted a systematic review of neuroimaging studies analyzing the effects of serotonergic hallucinogens in man .