The pattern of fMRI activation with STN DBS reveals symptom-specific networks

The network changes elicited by deep brain stimulation (DBS) in Parkinson's disease (PD) remain incompletely understood. We used functional MRI (fMRI) during active stimulation of the subthalamic nucleus (STN) to identify brain networks associated with clinical improvement. Forty PD patients (61 y ±8, 40% female) underwent 3-Tesla fMRI during active stimulation. Stimulation-induced changes in brain activity were correlated with outcomes (tremor, rigidity, bradykinesia, and axial instability). Symptom-specific fMRI response maps revealed distributed networks associated with long-term motor improvement, but ROI-based models showed poor out-of-sample performance and limited spatial stability. In contrast, somatomotor network modulation demonstrated symptom-specific coupling preferentially in rigidity improvement (ΔR² = 0.24, p_FDR = 0.01) and bradykinesia (ΔR² = 0.13, p_FDR = 0.07). Normative connectivity explained variance less consistently. These findings support the use of patient-specific fMRI as a tool for studying the neural mechanisms of DBS and highlight the importance of distributed network engagement in mediating therapeutic benefit.