Distinct Brain Energy Patterns Found for Psilocybin, LSD, and 2C‑B

Researchers gave 48 healthy rats a single injection of either psilocybin, LSD, or 2C‑B, or saline. Each rat underwent three PET scans—before the drug, soon after, and a week later—using a radioactive glucose tracer that maps brain energy use. The doses filled 51–70% of serotonin 2A receptors, a level linked to strong psychedelic effects in humans. The study found that the three compounds produced distinct metabolic fingerprints, questioning the common practice of treating them as interchangeable.

Acute metabolic signatures differ

Acute scans revealed drug‑specific signatures. Psilocybin raised energy use in the dorsal striatum and the insula, areas linked to habit and bodily awareness, but did not affect frontal cortex activity in rats. LSD produced widespread decreases in frontal metabolism while boosting activity in midbrain regions, including the amygdala and hypothalamus. 2C‑B shared LSD’s frontal suppression but showed a larger dopamine‑producing hotspot in the midbrain and also increased insula activity.

A week later, most acute changes faded. Psilocybin still showed heightened insula activity and a strengthened link to the prefrontal cortex, while LSD and 2C‑B had modest, region‑specific decreases. The authors cautioned that the study was small, measured relative metabolism, and did not assess behavior, so clinical implications remain speculative.