Deep brain stimulation (DBS) is an effective long-term treatment for motor symptoms in advanced Parkinson's disease (PD). The most frequently used target is the subthalamic nucleus (STN). For some patients, the beneficial motor effects may be accompanied by cognitive impairment and other neuropsychiatric disturbances. PD is associated with impaired functioning of the basal ganglia, their interactions with cortical structures resulting in changed functional cortical connectivity. STN plays an integrative role in motor and cognitive functioning and its stimulation probably partly restores the physiological coupling between the cortical areas, but the effect on the somatomotor network may differ from the effects on the cognitive networks. Thus, we will use scalp high-density EEG under on and off conditions and also direct intracerebral recordings of the STN combined with scalp recording in the subgroup. High performance analytical methods will be used to clarify the STN DBS impact on motor and cognitive cortical networks and correlated with longitudinal clinical examination.