A dual-pathway dysregulation in prefrontal-habenular circuits mediates stress susceptibility.

Chronic stress disrupts emotional homeostasis, leading to resilience or susceptibility through unclear mechanisms. Here, we identify a dual-pathway mechanism in the dorsomedial prefrontal cortex (dmPFC)-lateral habenula (LHb) circuit in male mice, where glutamatergic and GABAergic projections coordinately regulate stress responses. Chronic stress differentially modulates these pathways, inducing susceptibility-specific hyperactivity in dmPFC-innervated LHb neurons by potentiating excitatory and suppressing inhibitory inputs, disrupting long-range excitatory/inhibitory (E/I) balance. Chemogenetic recapitulation of this imbalance exacerbates LHb hyperactivity and stress susceptibility, whereas restoring balance promotes resilience. Mechanistically, stress-susceptible mice exhibit impaired ATP-P2X2R signaling in GABAergic neurons, leading to disinhibition of the excitatory pathway via local microcircuits and weakening of the inhibitory projection, resulting in E/I imbalance. This disruption ultimately causes LHb hyperactivity and susceptibility. Collectively, these results reveal that coordinated regulation of opposing dmPFC-LHb pathways by ATP-P2X2R signaling gates stress susceptibility, providing a dual-pathway dysregulation mechanism for stress-induced maladaptation and a potential therapeutic target for depression.