Mineralization of the globus pallidus following excitotoxic lesions of the basal forebrain

The excitotoxin N-methyl aspartic acid was injected into the rat nucleus basalis to destroy basal forebrain cholinergic (BFC) neurons. In long-term survival experiments (up to 11 months post-lesion), conspicuous mineralized deposits were found in the globus pallidus and to a lesser extent in the thalamus. Deposits stained in a manner consistent with a composition of calcium and iron. Typically, deposits were absent from the center of the injection site, where BFC cell loss was most severe, but were present within the ventral and lateral globus pallidus where there was substantial sparing of BFC neurons. The similarity of this pathology to basal ganglia calcification and its relationship to Alzheimer's Disease and Down's syndrome is discussed.