The autonomic spine — four theories, one causal stack, one load-bearing primary

The mechanism under the layers is autonomic regulation, and it is built from FOUR published, individually-falsifiable theories — Matt did not invent them, he composed them into a stack that operates at different levels of one system: • PREDICTIVE PROCESSING / Active Inference (Friston) — the computational frame: the brain minimizes prediction error; autonomic shifts are action policies to resolve it. • LC-NE ADAPTIVE GAIN (Aston-Jones & Cohen) — the gain control: tonic arousal is idle RPM, phasic bursts are throttle/precision; high-tonic/low-phasic = revved but imprecise (sensory overload). • NEUROVISCERAL INTEGRATION / Central Autonomic Network (Thayer & Lane) — the state switch: the prefrontal-vagal brake, indexed by HRV; low HRV = poor inhibitory control, rigid states. • PREDICTIVE ALLOSTATIC INTEROCEPTION (Barrett) — the feedback loop: the brain preempts bodily needs; chronic interoceptive prediction error = allostatic overload → protective sympathetic posture. The stack is not four rival guesses; it is a computational frame (PP) driving two control systems (LC-NE gain, NIM state-switch) feeding an effector (ANS) closed by an interoceptive dashboard. The red-team's fix names NIM/CAN — the vagal brake — as the LOAD-BEARING PRIMARY: it is the most measurable and most central, and the framework's survival is pinned to it. If HRV/vagal-brake fails to track dysregulation within-person, the framework fails. No escape onto the other three. SAFETY BOUNDARY — this is a research framework, NOT medical advice, NOT a diagnosis, NOT a treatment plan. It is adjunctive to, never a replacement for, a licensed physician. STOP and seek urgent care for red flags: chest pain, sudden neurological deficit, fainting, severe or rapidly worsening symptoms. The engine seals the LOGIC of this framework; it does NOT and CANNOT seal that any mechanism here is medically true — that awaits the trials named below.