The basal nucleus of Meynert in idiopathic Parkinson's disease.

The basal nucleus of Meynert (bnM) was examined in 6 patients with idiopathic Parkinson's disease and in 5 age-matched controls. The histopathological study was followed by a quantitative analysis of the magnocellular population of the nucleus, with the determination of the number of neurons and their nucleolar volume. In Parkinson's disease, there was a neuronal loss ranging from 29.9% to 68.3% (mean 45.8%) and numerous surviving cells containing Lewy inclusion bodies. The percentage loss of cells did not display a significant correlation with the age of the patients, the duration of the illness, the mental state or the drug regime. On the other hand, no significant differences in nucleolar volume of bnM neurons were detected between patients and controls. The damage of the basal nucleus of Meynert in Parkinson's disease is less severe than that generally observed in Alzheimer's disease, and is slightly more pronounced than that reported for progressive supranuclear palsy.