The function of the Neuroengineering core (Core D) is to develop new technologies that will open new research possibilities for the study of Parkinson's disease both within and outside the Center. The core will be responsible for the development of a microstimulator for chronic brain stimulation in rats. This device, which is not available commercially, will be used in all three projects of the Center to study the cellular and molecular effects of deep brain stimulation of the subthalamic nucleus, a novel and effective treatment for Parkinson's disease. In addition, the core will develop novel miniaturized biosensors for the detection of glutamate and GABA with greater spatial and temporal resolution than currently possible. These biosensors will be developed to permit highly localized rapid measurements of neurotransmitter release in project 3.