THE AUTONOMIC-RELATED CORTEX - PATHOLOGY IN ALZHEIMERS-DISEASE

Alzheimer's disease (AD) causes progressive deterioration of cognition and behavior. Memory dysfunction is the hallmark but there are also c hanges in behavior, emotion and autonomic functions, which cannot he e xplained simply as a consequence of memory impairment These observatio ns suggest that the natural disease process of AD involves not only me mory-related neural structures, but also specific neural systems relat ed to other behaviors, emotion and autonomic functions. Since recent e vidence has indicated a primary role far ventromedial frontal (VWF) co rtex in such functions, we examined laminar distribution of neurofibri llary tangles and Alz 50 immunoreactive neurons in subdivisions of VMF cortex in 20 AD patients and seven age-matched controls. The densitie s of pathological changes were: (i) highest in the posteromedial mesoc ortical regions, particularly Brodmann's area 25 (A25), posterior orbi tofrontal cortex (POF) and anterior insula (Al); (ii) of comparable se verity between posteromedial mesocortical regions and most temporal co rtices, excluding only the entorhinal cortex and temporal pole; and (i ii) located predominantly in layer III and especially layer V. Further analysis demonstrated selective pathology in layer V of A25, POF and Al that would disrupt direct cortico-autonomic projections. This is th e first study to detail severe AD pathology in these autonomic-related cortices, which could contribute to the behavioral changes, emotional disturbance and autonomic dysregulation that often accompany AD.