Nasal Breathing, Fear Extinction, and Memory Encoding: The Olfactory-Amygdala Pathway as Displacement Regulator

Nasal breathing provides a direct anatomical pathway from airflow to the amygdala via the olfactory bulb — the only cranial nerve that bypasses the thalamus. We apply the displacement framework to show that nasal breathing is a continuous suppressor of D(xi_fear), the displacement of fear-system activation from its ground state S0_fear. Three mechanisms: olfactory-amygdala direct inhibition during nasal inhalation; vmPFC oxygenation enabling top-down amygdala regulation; hippocampal theta entrainment supporting extinction memory consolidation.