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 .
Effects of the South American Psychoactive Beverage Ayahuasca on Regional Brain Electrical Activity in Humans: A Functional Neuroimaging Study Using Low-Resolution Electromagnetic Tomography
Ayahuasca , a South American psychotropic plant tea obtained from Banisteriopsis caapi and Psychotria viridis , combines monoamine oxidase-inhibiting β-carboline alkaloids with N , N-dimethyltryptamine ( DMT ) , a psychedelic agent showing 5-HT2A agonist activity . In a clinical research setting , ayahuasca has demonstrated a combined stimulatory and psychedelic effect profile , as measured by subjective effect self- assessment instruments and dose-dependent changes in spontaneous brain electrical activity , which parallel the time course of subjective effects . In the present study , the spatial distribution of ayahuasca-induced changes in brain electrical activity was investigated by means of low-resolution electromagnetic tomography ( LORETA ) . Electroencephalography recordings were obtained from 18 volunteers after the administration of a dose of encapsulated freeze-dried ayahuasca containing 0.85 mg DMT/kg body weight and placebo . The intracerebral power density distribution was computed with LORETA from spectrally analyzed data , and subjective effects were measured by means of the Hallucinogen Rating Scale ( HRS ) . Statistically significant differences compared to placebo were observed for LORETA power 60 and 90 min after dosing , together with increases in all six scales of the HRS . Ayahuasca decreased power density in the alpha-2 , delta , theta and beta-1 frequency b and s. Power decreases in the delta , alpha-2 and beta-1 b and s were found predominantly over the temporo-parieto-occipital junction , whereas theta power was reduced in the temporomedial cortex and in frontomedial regions . The present results suggest the involvement of unimodal and heteromodal association cortex and limbic structures in the psychological effects elicited by ayahuasca
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 .