The Amygdala as Jaw Door Opener: Threat-Initiated Mandibular Protrusion, Airway Preparedness, and the Fear-Airway-Brain Feedback Loop

The amygdala initiates jaw clenching as an adaptive airway-widening response to threat. Via CeA → trigeminal motor nucleus → lateral pterygoid, amygdala activation protrudes the mandible, activating the genioglossus and widening the upper airway. This constitutes a complete feedback loop: D(xi_threat) → amygdala → jaw → airway → cerebral oxygenation → threat resolution. Bruxism is reframed as nocturnal looping of this circuit against unresolved threat memories.