The external globus pallidus in patients with Parkinson's disease and progressive supranuclear palsy

• Published in: Movement disorders Vol. 14; no. 4; pp. 626 - 633
• Main Authors: Hardman, Craig D., Halliday, Glenda M.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.07.1999; Wiley
• Subjects: Age Factors; Aged; Aged, 80 and over; Basal Ganglia - pathology; Biological and medical sciences; Case-Control Studies; Cell Count; Cerebral Cortex - pathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disease Progression; External globus pallidus; Female; Globus Pallidus - metabolism; Globus Pallidus - pathology; Humans; Linear Models; Male; Medical sciences; Middle Aged; Nerve Degeneration - metabolism; Nerve Degeneration - pathology; Neural Pathways - pathology; Neurodegeneration; Neurofibrillary Tangles - pathology; Neurology; Parkinson Disease - metabolism; Parkinson Disease - pathology; Parkinson's disease; Parvalbumin; Parvalbumins - metabolism; Progressive supranuclear palsy; Supranuclear Palsy, Progressive - metabolism; Supranuclear Palsy, Progressive - pathology; Tropical medicine; Human; Nervous system diseases; Supranuclear ophthalmoplegia; Parkinson disease; Exploration; Pallidum; Cerebral disorder; Progressive; Pathology; Eye disease; Central nervous system disease; External; Degenerative disease; Oculomotor syndrome; Brain stem syndrome; Comparative study; Brain (vertebrata); Extrapyramidal syndrome
• ISSN: 0885-3185; 1531-8257
• DOI: 10.1002/1531-8257(199907)14:4<626::AID-MDS1012>3.0.CO;2-U

Underactivity of the external segment of the globus pallidus is thought to contribute to the generation of parkinsonian hypokinetic symptoms in association with striatal dopaminergic dysfunction and overactivity of the subthalamus. These symptoms can be corrected by neurosurgical techniques aimed at normalizing subthalamic overactivity. The aim of the present study was to compare the amount of neurodegeneration and changes in the calcium‐binding protein parvalbumin in the external segment of the globus pallidus in parkinsonian disorders. Cases with progressive supranuclear palsy were compared with cases with Parkinson's disease and control subjects. The number of neurones and neurofibrillary tangles was estimated using unbiased stereologic techniques. The external segment of the globus pallidus in Parkinson's disease was not significantly different from that in control subjects. In contrast, most patients with progressive supranuclear palsy had significant neurodegeneration of the external pallidum, particularly patients with significant degeneration of both the subthalamus and substantia nigra. These results suggest that the parkinsonian symptoms in progressive supranuclear palsy are caused by the degeneration of the external segment of the globus pallidus because such degeneration would increase thalamic inhibition through the basal ganglia output nuclei, particularly in patients with a loss of excitatory drive from the subthalamus.