Cortical Destruction and Cell Death in Alzheimer’s Disease

Abstract

The neuronal constituents of the cerebral cortex are comprised of many types of pyramidal neurons and a heterogeneous group of nonpyramidal nerve cell types (5–8). Most types of pyramidal cells generate an axon which enters the white matter and terminates in other cortical areas or subcortical structures. The axon and frequently its collateral branches are myelinated distal to the initial segment. Most nonpyramidal cells, by contrast, generate an axon that branches profusely in the vicinity of the parent soma. Functional maturity of most cortical projection cells is achieved only after myelination of the axon and establishment of bidirectional synaptic contacts to local circuit neurons. Projection cells, oligodendroglial cells, and local circuit neurons are the essential components of a cortical functional unit (Fig. 1)