How the brain tells inside from outside

One architecture, adjudicating what is real. The content generator runs continuously by default; the external world enters only at the comparison, where it constrains what is already being generated. Select a syndrome to see which component or pathway fails — and whether insight survives, the sign that localizes the lesion.

arousal / state gate — keeps the system online & connected to the world (brainstem–thalamic, cholinergic–aminergic) ↑ reported experience & causal narrative ⟳ generates by default prediction error ↑ verdict: real / not-real precision / weighting sets precision generated content ↑ cancels self-caused input sensory input → The Interpreter builds causal self-narrative (L-hemisphere) Reality-checker anterior mPFC · BA10 · paracingulate Prior / precision dopaminergic cortico-striatal loops Comparison generated content vs world = prediction error Self-signal filter corollary discharge / forward model Content generator sensory cortex — runs continuously; world constrains, doesn't drive External world afferent sensory input Self-action motor command → efference copy
destroyed / failed over-weighted or blinded offline (physiological) intact flow disrupted flow