A new study suggests that four psychoactive compounds work in surprisingly similar ways, and that they break down the separation between how we think internally and how we perceive the outside world The hallucinogenic mushroom  Psilocybe pelliculosa , which contains psilocybin shroom360 via Wikimedia Commons under CC-BY-SA-3.0 Mind-altering psychedelics continue to show promising research results as potential therapeutics for certain mental health conditions, such as post-traumatic stress disorder and depression. But scientists still don’t know exactly how these substances affect the brain. Now, researchers have identified a “signature” pattern of neural activity evoked by different psychedelics—including LSD and psilocybin—after analyzing more than 500 brain scans from 267 participants across the globe.…