Positron emission tomography for exploring the mechanism of action in the nucleus subthalamicus

Activation studies with (H2O)-O-15 and positron emission tomography (PET) o ffer the opportunity to study regional cerebral function in man in vivo und er different conditions with the analysis of condition specific changes in regional cerebral blood flow (rCBF) as index of synaptic activity. The comb ination of PET and deep brain stimulation is unique to study the effects of discrete perturbations at different target structures throughout the basal ganglia-thalamocortical circuitries as functional magnetic resonance imagi ng (fMRI) cannot be used in patients with implanted stimulators. The contri bution of PET activation studies to the understanding of deep brain stimula tion will be presented with a study on Parkinson's disease patients with el ectrodes chronically implanted in the subthalamic nucleus.