Neuropathic pain drives time-dependent reorganization of corticostriatal circuits

Abstract

Chronic pain fundamentally alters sensorimotor integration and motivated behaviors, yet the neural mechanisms underlying this transition remain poorly understood. The striatum, composed of dopamine receptor type 1 (D1)- and type 2 (D2)-expressing spiny projection neurons (SPN), integrates cortical sensory and motor inputs to coordinate movement and motivation, making it a critical candidate for mediating pain-induced behavioral adaptations. Although spinal and cortical pain circuits are well-characterized in limited phases of pain, how corticostriatal pathways and distinct striatal cell populations contribute to the transition from acute to chronic pain states remains unclear. Here we show that neuropathic pain, after spared nerve injury in mice, produces temporally distinct, cell-type-specific changes in striatal SPN activity and corticostriatal plasticity that evolve across acute to chronic pain phases. D1 SPNs exhibit smaller amplitude and slower calcium signals during acute pain stages that persist through early chronic phases, while D2 SPNs show delayed response timing during later chronic stages, but also stimulus-specific alterations in neural activity throughout acute and chronic pain states. Critically, primary somatosensory cortex inputs to D2 SPNs develop depressing synapses specifically during intermediate chronic pain phases ([~]25 days post-injury) that disappear during more severe chronic stages (>3 months), suggesting a failed compensatory mechanism. These findings reveal that striatal circuits undergo dynamic, time-dependent reorganization after peripheral injury, with D1 and D2 pathways contributing distinct temporal signatures to pain-related behavior. The identification of critical windows of striatal plasticity provides new targets for therapeutic interventions that could prevent or reverse chronic pain states by modulating specific corticostriatal circuits during vulnerable transition periods.