Neurochemical Studies of Early-Onset Alzheimer's Disease: Possible Influence on Treatment

DEMENTIA is most commonly associated with Alzheimer's disease, a disorder with widespread social and economic implications. A distinction has often been made between presenile and senile forms of the disease, but since similar histologic changes are seen (senile plaques and neurofibrillary tangles in the cortex), this division is disappearing. Recent research on Alzheimer's disease suggests that there is a selective deficit in some subcortical and brain-stem neurons that have long axons projecting toward the neocortex. Much of the evidence implicating these ascending tracts has been derived from studies of the cholinergic neurotransmitter system, although ascending noradrenergic and serotoninergic neurons may.