Galvanic noisy vestibular stimulation (NVS) to Parkinson disease (PD) patients could relieve balance impairments. This study was designed to observe changes of the neuronal activity in the substantia nigra pars reticulata (SNr) of an animal PD model following NVS and its neural pathway. To make an animal model of PD, 6-hydroxydopamine (6-OHDA) was injected to the right medial forebrain bundle of Sprague-Dawley rats. Rats (male, 250~300g, n=35) were anesthetized with isoflurane. Two to three weeks after 6-OHDA lesion, extracellular single-unit activity of the ipsilesional SNr was recorded before and after NVS of the horizontal semicircular canal nerve unilaterally or bilaterally under anesthesia. The baseline neuronal activity was measured during 2 minutes before NVS. NVS continued for 5 minutes and then a recording was resumed for 2 minutes. Extracellular single-unit activity of the parafascicular nucleus (PFN) of the thalamus to stimulation of the vestibular nerve was recorded. Evoked field potentials with polysynaptic nature were recorded in the contralateral PFN to the stimulation site but not in the ipsilateral PFN. Recording the single-unit activity of the ipsilesional SNr revealed that slow oscillations (<2.5Hz) of SNr spike trains significantly increased following 6-OHDA lesion. These slow oscillations were remarkably reduced and the irregularity of firing pattern was also significantly decreased by unilateral or bilateral NVS. Furthermore, the contralateral or bilateral NVS to hemi-lesioned side tended to decrease the neuronal activity of SNr neurons, while the ipsilateral NVS showed the increase tendency of that, relatively. Theses electrophysiological evidences suggest that the noisy electrical stimulation to the peripheral vestibular apparatus may modulate abnormal neuronal activities of basal ganglia in an animal model of PD through the vestibulo-thalamo-striatal pathway.