Functional magnetic resonance imaging during deep brain stimulation: A pilot study in four patients with Parkinson's disease

Functional magnetic resonance imaging (fMRI) was performed in patients with Parkinson's disease during deep brain stimulation of the subthalamic nucle us (three patients) and during deep brain stimulation of the ventral interm edius nucleus of the thalamus (one patient). All showed an increase in bloo d oxygenation level-dependent signal in the subcortical regions ipsilateral to the stimulated nucleus. This effect cannot be simply explained by a mec hanism of depolarization blockade; rather, it is caused by overstimulation of the target nucleus, resulting in the suppression of its spontaneous acti vity. We confirm that fMRI during deep brain stimulation is a safe method w ith considerable potential for elucidating the functional connectivity of t he stimulated nuclei. (C) 2001 Movement Disorder Society.