Classical hallucinogens and neuroimaging: A systematic review of human studies: Hallucinogens and neuroimaging.
Level 2 - randomized trial
Systematic review of heterogeneous human neuroimaging studies
PubMed 27810345 · doi:10.1016/j.neubiorev.2016.10.026
What was done
Authors systematically reviewed human neuroimaging studies (using MRI, fMRI, PET, and SPECT) investigating the effects of serotonergic hallucinogens (ayahuasca, DMT, psilocybin, LSD, and mescaline). Searches were conducted in PubMed, Lilacs, and SciELO up to April 12, 2016. Out of 279 identified records, 25 studies met inclusion criteria.
What was found
No numerical values or effect sizes are reported in the abstract. Qualitatively, acute administration was associated with excitation of frontolateral/frontomedial cortex, medial temporal lobe, and occipital cortex, alongside inhibition of the default mode network. Long-term use was linked to posterior cingulate cortex thinning, anterior cingulate cortex thickening, and decreased neocortical 5-HT 2A receptor binding.
Why it matters
This synthesis outlines the neurobiological correlates of classic psychedelics, highlighting default mode network inhibition and fronto-temporal-occipital modulation as key mechanisms underlying their perceptual and mood-altering effects.
Limits
The review notes high methodological heterogeneity and small sample sizes across included studies. Specific participant demographics, detailed scan protocols, and quantitative meta-analytic data were not reported in the abstract.
Cited by
- supports Classical psychedelics, including psilocybin, LSD, DMT, and mescaline, produce their effects by binding to the serotonin 2A (5-HT2A) receptor.