The prepiriform cortex in dementia of the Alzheimer type.

Histopathologic examination of the prepiriform cortex (PPC) in four documented cases of dementia of the Alzheimer type revealed increased numbers of neurofibrillary tangles and neuritic plaques. These findings indicate that some early- and late-onset cases of Alzheimer's disease may be associated with significant damage to the PPC, a relay center of the mammalian olfactory system that has extensive connections with structures concerned with cognitive and behavioral functions. Involvement of the PPC may be related to the complex neuropsychiatric manifestations observed in this disorder.