The Trapped Gate: OCD and PTSD as Opposite Failures of Signal Competition

This paper proposes that OCD and PTSD are not separate conditions requiring separate frameworks but structurally opposite failures of the same gate competition mechanism at the thalamic reticular nucleus. In OCD a cortico-striato-thalamo-cortical loop fails to terminate, continuously regenerating the same signal coalition at full amplitude regardless of what competes against it — the gate cannot move on. In PTSD amygdala signals carry maximum synaptic weight while vmPFC competitive amplitude collapses, producing continuous threat dominance at the gate — the gate cannot escape. The compulsion in OCD is the prefrontal cortex attempting to generate a resolution signal strong enough to override the loop, temporarily succeeding, and failing again when the loop resumes. The 30% treatment resistant population in both conditions is predictable from this framework. The OCD-PTSD comorbidity is the hardest treatment profile — loop termination must precede amplitude restoration or neither intervention holds. Fix the competition and the gate fixes itself.