A HISTOMETRICAL STUDY ON THE GLOBUS-PALLIDUS IN HUNTINGTONS-DISEASE

Pathological change of the globus pallidus (GP) in 6 cases of Huntingt on's disease (HD) was examined histometrically by comparison with 10 n ormal control cases. All but 1 case of HD were in late stages of the d isease. Total neuronal count, area of GP, and neuronal cell density we re measured in 5 selected regions of coronal sections taken along the antero-posterior axis. Contrary to the findings of previous reports, n o neuronal depletion was recognized in HD in any region despite marked atrophy of tissue bulk. The atrophy was more severe in the external s egment (GP(e)) than in the internal segment (GP(i)). Reactive astrocyt osis and fibrillary gliosis were observed in the atrophic lesions. The se results indicate that atrophy of the GP can be attributed to striat o-pallidal fiber loss and not to neuronal depletion even in the late s tages. These findings support the hypothesis that loss of striato-GP(e ) fibers plays the most important role in choreic movements in HD. It remains to be determined whether the pallidal neurons are also preserv ed in the end stage of the disease.