Neuronal loss in the basal nucleus of Meynert in progressive supranuclear palsy.

A morphometric study of the basal nucleus of Meynert (bnM) has been performed in a 70-year-old man with a 4-year history of pathologically confirmed progressive supranuclear palsy (PSP). An important neuronal loss (52%) was demonstrated in the bnM. This finding has not been previously documented with morphometric methods in PSP, but the involvement of the bnM is well known in other related conditions, i.e., Parkinson's disease, Alzheimer's disease, and Parkinson-dementia complex of Guam. Our findings yield support to the view that the involvement of the bnM, a nucleus with complex connections with various subcortical structures and diffuse cholinergic projections on the neocortex, could play an important role in the physiopatholog of subcortical dementia.