Some animal studies suggest psilocybin might help the brain rewire itself after injury — a property called neuroplasticity. But animal results and human trials are very different things. Before researchers can give psilocybin to a human with a brain injury, they need to figure out the right dose, prove it's safe for that specific condition, and get government permission (called an IND, or Investigational New Drug application) from the FDA. That groundwork simply hasn't been done yet for traumatic brain injury. This matters because if the animal findings do translate to humans, it could open a completely new use for psilocybin beyond mental health.
Rodent 5-HT2A restoration findings are preclinical and lack the dose-response and safety translation work needed for IND. Falsifiable by any ClinicalTrials.gov (or equivalent registry) listing of a psilocybin TBI/neuroplasticity human trial reaching first-patient-dosed in the window.