Pallidotomy in Parkinson's disease increases supplementary motor area and prefrontal activation during performance of volitional movements an H2(15)O PET study

Abstract

Supplementary motor area and right dorsal prefrontal cortex activation in Parkinson's disease is selectively impaired during volitional limb movements. Since posteroventral pallidotomy improves motor performance in Parkinson's disease patients 'off' medication (i.e. off medication for 9-12 h), we hypothesized that it would also concomitantly increase supplementary motor area and dorsal prefrontal cortex activation. Six Parkinson's disease patients with a median total motor Unified Parkinson's Disease Rating Scale (UPDRS) of 52.5 (range 34-66) 'off' medication underwent unilateral right posteroventral pallidotomy. The patients had H2(15)O PET when 'off' medication before and 3-4 months after surgery. Each PET study comprised four to six measurements of regional cerebral blood flow either at rest or while performing regularly paced joystick movements in freely selected directions (forward, backward, left or right) using the left hand. Pre- and postoperative scans were performed in an identical manner and the associated levels of activation were compared using statistical parametric mapping. After pallidotomy, the median total motor UPDRS score 'off' medication decreased by 34.7% (P = 0.03) and mean response times of joystick movements following the pacing tones improved by 13.8% (P = 0.08). Relative increases in activation of the supplementary motor area and right dorsal prefrontal cortex were observed during joystick movements (P < 0.001). Decreased activation was seen in the region of the right pallidum (P = 0.001). We conclude that pallidotomy reduces pallidal inhibition of thalamocortical circuits and reverses, at least partially, the impairment of supplementary motor area and dorsal prefrontal cortex activation associated with Parkinson's disease.

Cerebral blood flow changes induced by pedunculopontine nucleus stimulation in patients with advanced Parkinson's disease: A [15O] H2O PET study

“…Indeed, greater activations of these regions were associated with [Piallat et al, 2008] and that SMA is clearly involved in internally generated motor actions [Debaere et al, 2003;Deiber et al, 1991;Jenkins et al, 2000;Ogawa et al, 2006;Rao et al, 1997]. SMA underactivity has been proposed to play an important role in the pathophysiology of PD motor symptoms [DeLong, 1990;Georgiou et al, 1993;Playford et al, 1992;Sabatini et al, 2000;Samuel et al, 1997]. Several imaging studies have shown how increased activation of SMA is often associated with motor improvement induced by effective treatments, such as GPi and STN surgery [Brooks and Samuel, 2000] as well as dopaminergic medications [Haslinger et al, 2001;Jenkins et al, 1992].…”

Basal ganglia hypoactivity during grip force in drug naïve Parkinson's disease

“…In general, studies have shown that PD leads to reduced regional cerebral blood flow (rCBF) and reduced blood oxygenation level dependent (BOLD) activation in the striatum, prefrontal cortex, and supplementary motor area (SMA) (Dirnberger et al, 2005;Grafton et al, 2006;Playford et al, 1992;Samuel et al, 1997;Yu et al, 2007). Two fMRI studies found that PD patients of moderate severity who had been treated with anti-parkinsonian medications for many years had increased BOLD activation compared to controls in the primary motor cortex (M1) when studied following a 12-h withdrawal from medication (Sabatini et al, 2000;Yu et al, 2007).…”

Modified Fluorodeoxyglucose Metabolism in Motor Circuitry by Subthalamic Deep Brain Stimulation

“…The decrease in cerebral blood flow in the supplementary motor area has been correlated with the improvement of rigidity [13]. However, some investigations indicated that during motor execution, STN DBS induced an increased activation of the supplementary motor area [14,15,16]. The inconsistency might originate from the heterogeneity of patients enrolled in different studies.…”