Classical hallucinogens and neuroimaging: A systematic review of human studies: Hallucinogens and neuroimaging.
Serotonergic hallucinogens produce alterations of perceptions, mood, and cognition, and have anxiolytic, antidepressant, and antiaddictive properties. These drugs act as agonists of frontocortical 5-HT2Areceptors, 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. Studies published in the PubMed, Lilacs, and SciELO databases until 12 April 2016 were included using the following keywords: "ayahuasca", "DMT", "psilocybin", "LSD", "mescaline" crossed one by one with the terms "mri", "fmri", "pet", "spect", "imaging" and "neuroimaging". Of 279 studies identified, 25 were included. Acute effects included excitation of frontolateral/frontomedial cortex, medial temporal lobe, and occipital cortex, and inhibition of the default mode network. Long-term use was associated with thinning of the posterior cingulate cortex, thickening of the anterior cingulate cortex, and decreased neocortical 5-HT2Areceptor binding. Despite the high methodological 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.
Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil. Electronic address: banisteria@gmail.com.
Rafael G
RG
Dos Santos
Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil; National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.
Flávia L
FL
Osório
Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil; National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.
José Alexandre S
JAS
Crippa
Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil; National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.
Jaime E C
JEC
Hallak
D002540:Cerebral Cortex; D006213:Hallucinogens / Q000378:metabolism*; D006801:Humans; D008297:Male; D059906:Neuroimaging; D011562:Psilocybin; D044402:Receptor, Serotonin, 5-HT2A
D006213:Hallucinogens; D044402:Receptor, Serotonin, 5-HT2A; D011562:Psilocybin
Ayahuasca; DMT; Default mode network; Hallucinogens; LSD; Mescaline; Neuroimaging; PET; Psilocybin; SPECT; fMRI