Psychedelics alter brain connectivity, pooled study finds

A pooled analysis of more than 500 fMRI scans from studies of five psychedelics reports increased communication between sensory-processing and higher-order brain regions, and the results were published in Nature Medicine.

Researchers combined brain imaging data from nearly a dozen functional M.R.I. studies to examine how classic psychedelics affect the human brain. The pooled dataset included more than 500 scans from 267 participants across studies of LSD, psilocybin, mescaline, DMT and ayahuasca, and the analysis was published in Nature Medicine. The team reports that these compounds increase coordination between sensory-processing areas and higher-order regions involved in abstract thought and self-reflection. Authors said the unified approach helped clarify which previously reported effects are robust and which are more uncertain. Key results: - The analysis pooled fMRI data from studies across five countries and five psychedelic substances. - All five drugs showed effects on brain regions that coordinate perception and action, increasing cross‑talk between sensory and higher-order networks. - The study did not find consistent evidence that psychedelics universally disintegrate major networks such as the default mode network; results were more nuanced. - The unified framework is presented as a reference point for research and for comparing brain biomarkers across new compounds. Summary: The pooled analysis offers a shared reference for how classic psychedelics influence brain connectivity and highlights increased interaction between sensory and abstract-processing regions. Researchers and outside experts noted that harmonizing imaging methods and examining factors like age and sex remain areas for further study.