Magnetic resonance microscopy of iron in the basal forebrain cholinergic structures of the aged mouse lemur

Increased non-heme iron levels in the brain of Alzheimer's disease (AD) pat ients are higher than the levels observed in age matched normal subjects. I ron level in structures that are highly relevant for AD, such as the basal forebrain, can be detected post mortem with histochemistry. Because of the small size of these structures, in vivo MR detection is very difficult at c onventional field magnets (1.5 and 4 T). In this study, we observed iron de posits with histochemistry and MR microscopy at 11.7 T in the brain of the mouse lemur, a strepsirhine primate which is the only known animal model of aging presenting both senile plaques and neurofibrillary degeneration. We also examined a related species, the dwarf lemur. Iron distribution in aged animals (8 to 15 years old) agrees with previous findings in humans. In ad dition, the high iron levels of the globus pallidus is paralleled by a comp arable contrast in basal forebrain cholinergic structures. Because of the e nhancement of iron-dependent contrast with increasing field strength, micro scopic magnetic resonance imaging of the mouse lemur appears to be an ideal model system for studying in vivo iron changes in the basal forebrain in r elation to aging and neurodegeneration. (C) 1999 Elsevier Science B.V. All rights reserved.