Outlining Biological Effects of Subthalamic Deep Brain Stimulation in Parkinson's Disease Patients.

Inclusion Criteria: * clinically established diagnosis of PD according to the criteria of the Movement Disorder Society (MDS) (Postuma et al., Mov Disord 2015); * a minimum disease duration of 4 years; * eligibility for STN-DBS surgery according to Core Assessment Program for Surgical Interventional Therapies in PD (Defer et al., Mov Disord 1999); * age between 18 and 75 years. Exclusion Criteria: * inability to express an informed consent; * moderate or severe cognitive impairment (score \< 24 on the Mini-Mental State Examination); * severe psychiatric symptoms (e.g., psychosis, major depression); * previous neurosurgical interventions for PD; * pregnancy; * ongoing inflammatory or autoimmune diseases; * chronic infectious diseases; * active neoplasms; * chronic intake of anti-inflammatory drugs (e.g. steroids or NSAIDs).