Metabolic correlates of pallidal neuronal activity in Parkinson's disease

• Published in: Brain (London, England : 1878) Vol. 120; no. 8; pp. 1315 - 1324
• Main Authors: EIDELBERG, D, MOELLER, J. R, FAZZINI, E, BERIC, A, KAZUMATA, K, ANTONINI, A, STERIO, D, DHAWAN, V, SPETSIERIS, P, ALTERMAN, R, KELLY, P. J, DOGALI, M
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-08-1997; Oxford Publishing Limited (England)
• Subjects: Aged; Biological and medical sciences; Consciousness; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Globus Pallidus - cytology; Globus Pallidus - metabolism; Globus Pallidus - surgery; Glucose - metabolism; Humans; Intraoperative Period; Magnetic Resonance Imaging; Male; Medical sciences; Middle Aged; Neurology; Neurons - metabolism; Parkinson Disease - diagnostic imaging; Parkinson Disease - metabolism; Parkinson Disease - surgery; Parkinson's disease; Thalamus - cytology; Thalamus - metabolism; Tomography, Emission-Computed; Radionuclide study; Human; Nervous system diseases; Pathophysiology; Parkinson disease; Intraoperative; Glucose; Metabolism; Pallidum; Cerebral disorder; Nervous network; Network analysis; Central nervous system disease; Degenerative disease; Preoperative; Extrapyramidal syndrome; Positron; Emission tomography
• ISSN: 0006-8950; 1460-2156; 1460-2156
• DOI: 10.1093/brain/120.8.1315

We have used [18F]fluorodeoxyglucose and PET to identify specific metabolic covariance patterns associated with Parkinson's disease and related disorders previously. Nonetheless, the physiological correlates of these abnormal patterns are unknown. In this study we used PET to measure resting state glucose metabolism in 42 awake unmedicated Parkinson's disease patients prior to unilateral stereotaxic pallidotomy for relief of symptoms. Spontaneous single unit activity of the internal segment of the globus pallidus (GPi) was recorded intraoperatively in the same patients under identical conditions. The first 24 patients (Group A) were scanned on an intermediate resolution tomograph (full width at half maximum, 8 mm); the subsequent 18 patients (Group B) were scanned on a higher resolution tomograph (full width half maximum, 4.2 mm). We found significant positive correlations between GPi firing rates and thalamic glucose metabolism in both patient groups (Group A: r = 0.41, P < 0.05; Group B: r = 0.69, P < 0.005). In Group B, pixel-based analysis disclosed a significant focus of physiological-metabolic correlation involving the ventral thalamus and the GPi (statistical parametric map: P < 0.05, corrected). Regional covariance analysis demonstrated that internal pallidal neuronal activity correlated significantly (r = 0.65, P < 0.005) with the expression of a unique network characterized by covarying pallidothalamic and brainstem metabolic activity. Our findings suggest that the variability in pallidal neuronal firing rates in Parkinson's disease patients is associated with individual differences in the metabolic activity of efferent projection systems.