Changes in cerebral activity pattern due to subthalamic nucleus or internal pallidum stimulation in Parkinson's disease

Abstract

Injection of apomorphine, a dopaminergic agonist drug, decreases akinesia and increases cortical activityThe main driving force for the increased discharge of cells in GPi and SNr is thought to be overactivity of bl.the subthalamic nucleus (STN), which has excitatory projections to both structures. As a result, both GPi and STN have been identified as potential targets for neurosurgical procedures aimed at reducing basal ganglia outputs [6-111. Pallidotomy has now been performed successfully by many groups [6, 7, 9, 111. Two PET activation studies have confirmed that pallidotomy is accompanied by improvement of cortical activity during movement [12][13][14]. Theoretically, STN surgery has an advantage over pallidal surgery in that it can influence SNr as well as GPi activity and therefore could be more effective. A recent procedure has been to implant electrodes in STN or GPi for chronic electrical stimulation [8, lo]. Continuous high-frequency stimulation is believed to inactivate the target structure and to have an effect similar to a lesion.The advantage of the technique is that the effect is reversible and easily graded by changing electrical parameters. The effect is dependent on the frequency; frequencies lower than 30 Hz are ineffective and those greater than 50 Hz are effective [lo]. The aim of our study was to compare the effect of STN and GPi stimulation on the pattern of cortical activation during selfselected movements. We wanted (I) to examine the

Effect of bilateral subthalamic nucleus stimulation on parkinsonian gait

“…Brain activity was reduced in the medial frontal motor areas, including the SMA, in parkinsonian patients compared with control subjects who showed an increased brain activity in these areas [20]. Another study using positron emission tomography in the PD patients with STN stimulation showed that a movement-related increase in brain activity during effective STN stimulation was higher in SMA, cingulate cortex and dorsolateral prefrontal cortex than during ineffective stimulation [28].…”

High Frequency Stimulation of the Subthalamic Nucleus Eliminates Pathological Thalamic Rhythmicity in a Computational Model

“…In both of these cases, which we have not explored, our results suggest that the elimination of rhythmicity through DBS of STN would restore normal thalamic and cortical processing of sensorimotor inputs. While there is significant evidence that basal ganglia and cerebellar inputs to thalamus converge in cortical motor areas (Limousin et al, 1997;Hoover et al, 1999;Middleton et al, 2000;Bergman et al, 2002;Sestini et al, 2002), testing cortical responses to converging thalamic bursts induced by GPi, together with normal signals relayed from the cerebellum through other thalamic nuclei, remains an important step for future simulations and experiments.…”

Mechanisms and Targets of Deep Brain Stimulation in Movement Disorders

“…144 Comparison of PET data on responses between STN HFS and GPi HFS suggested that clinically effective stimulation of both targets led to supplementary motor cortex and cingulate cortex activation during a joystick task. 146 STN HFS produced higher cortical activation in general, however, and especially over the dorsolateral prefrontal cortex (DLPFC). Indeed, anatomical tracings have shown that STN neurons project to SNr, which in turn target the DLPFC through the nigral-receiving area of thalamus.…”