Quantitative morphometric analysis of the neurotoxic effects of the excitotoxin, ibotenic acid, on the basal forebrain

The effects of injections of the excitotoxin, ibotenic acid, into the nucleus basalis magnocellularis (NBM) were quantitatively studied. Besides destroying NBM neurons, ibotenic acid also produced comparable cell destruction within the adjacent medial amygdaloid nucleus and globus pallidus. Since the globus pallidus is spared in victims of senile dementia of the Alzheimer type (SDAT), although the adjacent NBM and amygdala are damaged, these data are not consistent with the theory that the damage to the basal forebrain seen in SDAT victims is produced by elevated levels of endogenous excitotoxin. These data also question the validity of using ibotenic acid-induced NBM lesions as a model of the cholinergic deficit in SDAT.