Proof Engine Verification: Critical periods of heightened cortical plasticity close permanently after early development, rendering the adult brain largely incapable of experience-dependent reorganization comparable to juvenile levels.

Verdict: DISPROVED - 5 independent methods have been demonstrated to reopen critical periods in adult brains, across visual, auditory, and social reward systems — directly contradicting "permanent" closure. - Enzymatic (ChABC), pharmacological (VPA, fluoxetine), psychedelic (psilocybin, LSD, MDMA), and genetic (A1R knockout) interventions all restore juvenile-like plasticity in adults. - Evidence spans animal models AND human subjects (VPA reopens absolute pitch learning in adult humans). - Adult thalamocortic