**Local Fields Potentials of the Subthalamic Nucleus in Patients With Parkinson's Disease** Parkinson's disease (PD) affects movement and can cause mood and behavior issues, known as neuropsychiatric fluctuations. The subthalamic nucleus, a small part of the brain, is critical in managing these symptoms. In this study, doctors use a device called PERCEPT (by Medtronic) to record brain activity in PD patients. This helps understand how neuropsychiatric and motor (movement) fluctuations change over time. "Beta frequency band" refers to certain brain wave patterns linked to movement problems. The study aims to develop "adaptive stimulation," which adjusts automatically to the patient's needs, making treatment more effective. **Key Points for Participants:** - **Participation Requirements:** Must be aged 30-75, diagnosed with PD, and have had recent surgery for brain stimulation. - **Study Duration:** Participants will be observed over time for changes in symptoms and brain activity. - **Exclusions:** If you have active psychosis, cannot provide consent, or are pregnant, you cannot join the study. This study could help improve how PD symptoms are managed, especially using adaptive brain stimulation.