Neurophysiological and neurochemical alterations during electrical stimulation of human caudate nucleus

Lumbar cerebrospinal fluid (CSF) norepinephrine (NE) concentrations were preoperatively determined in five patients using a radioenzymatic assay technique. Stereotaxic thalamotomy was performed using depth coagulating electrodes with stimulating points at 5.0-mm intervals along the shaft. No significant alterations in prestimulation lumbar CSF NE levels were noted 12 days after electrode installation. Stimulating points within the caudate nucleus were anatomically localized using ventricular landmarks and stimulation-induced neurophysiological responses were recorded. Twelve hours after intermittent electrical stimulation of the caudate nucleus, lumbar CSF NE concentrations were significantly decreased. Our data suggest the presence of noradrenergic pathways in man that are inhibited by caudate nucleus stimulation.