Functional Metabolic Mapping of the Rat Brain during Unilateral Electrical Stimulation of the Subthalamic Nucleus

Abstract

Summary:The alterations in local metabolic activity of several anatomically distinct brain areas were investi gated by means of the quantitative autoradiographic 2-deoxY-D-[l-14C]glucose method in awake rats during uni lateral electrical stimulation of the subthalamic nucleus (STH). Unilateral electrical stimulation of the STH in duced local metabolic activation (by 70% as compared with the control group), as well as distal metabolic acti vations in the substantia nigra reticulata (by 34%), globus pallidus (by 19%), entopeduncular nucleus (by 18%), deep layers of the superior colliculi (by 15%), and para fascicular thalamic nucleus (by 18%), ipsilaterally to the stimulated side. The ventrolateral motor thalamic nucleus as well as the limbic components, posterior cingulate cor tex, and anteroventral thalamic nucleus displayed bilat eral metabolic activations (by 20--28%). These results in dicate that, in addition to its known ipsilateral motor conThe subthalamic nucleus (STH) is generally con sidered to exert control over motor functions. The association of STH hypoactivity with the clinical syndrome of hemiballismus has long been docu mented (Whittier, 1947;Whittier and Mettler, 1949;Carpenter and Carpenter, 1951; Hammond et ai., 1979; Mitchel et ai., 1985a; Crossman, 1987 132nections, each STH is functionally related to the limbic system bilaterally. It is suggested that the STH is a site where the central motor information is accessible to the limbic system. Quantitative image analysis of individual serial sections in the STH, substantia nigra, and globus pallidus revealed a consistent dorsoventral pattern of to pographic interrelations. Stimulation of either the dorsal or the ventral subdivision of the STH induced always stronger activation in the dorsal compartment of the sub stantia nigra and in the ventral compartment of the globus pallidus. These results suggest that the earlier-described inversion of the dorsoventral functional correspondence between the substantia nigra and globus pallidus may be partly mediated via the subthalamic nerve cells projecting collateral axons to both these areas.

Subthalamic Ablation Reverses Changes in Basal Ganglia Oxidative Metabolism and Motor Response to Apomorphine Induced by Nigrostriatal Lesion in Rats

“…This confirms the fundamental role that subthalamic overactivity plays in the alterations of basal ganglion output in the setting of striatal dopaminergic denervation (Miller and DeLong, 1987;Bergman et al, 1994;Burbaud et ul., 1995). In particular, it confirms previous reports showing that manipulations of subthalamic activity directly affect the functional state of the entopeduncular nucleus and SNr neurons (Tzagournissakis et al, 1994;Benazzouz et al, 1995;Blandini and Greenamyre, 1995;Blandini et al, 1995).…”

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

“…Neither our results, nor those of others, however, have found their activity to be decreased 4, 5, 18. What is in agreement with the overstimulation hypothesis, however, is the STN‐stimulation‐evoked increased firing rate in the substantia nigra33 or the autoradiographically observed hyperactivation in the GP, substantia nigra, thalamus, and superior colliculi 34…”

The influence of the subthalamic nucleus upon the damage to the dopamine system following lesions of globus pallidus in rats

“…Firstly, despite original impressions, the contralateral loss was obviously not entirely dependent on the STN as it was still visible after lesions that inhibited the short‐term loss of DA cells. Secondly, when the metabolic consequences of stimulation were examined using a quantitative 2‐deoxyglucose measure (Tzagournissakis et al ., 1994) there was evidence of bilateral actions in the thalamic nuclei but the actions on the brain stem were not visible with (admittedly mild) stimulation of STN. We may thus have to look at the influence of thalamic pathways in this slow damage to the cells rather than rely on bilateral connections from STN to PPN and thence to the DA cells.…”