The cholinergic basal forebrain and its role in neurodegeneration

This review examines the cholinergic (Ch) basal forebrain and its role in neurodegeneration. Terminology used to describe Ch cells and the complex region of the basal forebrain are reviewed. Practical autopsy sampling and labeling strategies for Ch cells are discussed and illustrated with the goal of facilitating diagnostic work and autopsy-based studies of this region. The anatomic connectivity of the system is reviewed with an emphasis placed on the dense cholinergic input to the amygdala, the major target of the Ch basal forebrain, as well as the hippocampus. Ch and basal forebrain neuropathology in various neurodegenerative diseases is then briefly discussed, including more recent studies of TDP-43 proteinopathies. Finally, areas for further study that might further the understanding of the Ch system in neurodegeneration are emphasized.