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.