The closing edge: ego dissolution as memory destabilisation and extracellular control of the integration window

Psychedelic therapy is usually explained by what happens at the peak of the session. We argue the explanation sits on the wrong side of the experience. Drawing on first-person accounts of ego dissolution and on the reconsolidation literature, we set out a four-phase account in which the therapeutic event is not the dissolution and not the mystical peak, but the reassembly of self-referential memory on the way back, and the finite period that follows it. We write the account as a single operation on a memory, in which rewriting lowers the fidelity of a trace without erasing it and the post-session window is a write threshold that recovers with a time constant. Phase one, dissolution, is destabilisation, and it is governed by the same boundary conditions as any reconsolidation process, prediction error foremost. Phase two, the peak, is a state in which no identity is present to decide anything and, we argue, nothing is written. Phase three, the return, is restabilisation, and it is the only phase in which content enters the trace. Phase four is the window that stays open afterwards, which animal work now shows is a reopened critical period whose duration tracks the duration of the acute subjective effects. We then make the claim the field has not made: the timer on that window is extracellular. Critical period closure depends on perineuronal net formation, perineuronal nets gate reconsolidation and the persistence of remote fear memory, and matrix reorganisation is the common downstream signature of psychedelic-induced critical period reopening. The account yields testable predictions about integration timing, sessions that produce no change, and individual differences in window length, and it carries a hard consequence for practice: what is written on the way back may be false.