Nucleus basalis of Meynert pathology in the human brain after fatal head injury.

Dysfunction of the basal forebrain cholinergic system has been hypothesized to contribute to deficits of memory and cognition after head injury. We have previously reported reduced levels of choline acetyltransferase activity in the cerebral cortex of patients who died after a head injury, demonstrating that there is a loss of cortical cholinergic innervation. In the present study, we examined the nucleus basalis of Meynert (NBM), which provides cortical cholinergic innervation, in fatally head-injured patients and in controls. The majority of head-injured patients had histological evidence of neuronal damage in the NBM, which was due to mechanical distortion of the tissue and/or ischemic damage. The findings demonstrate that the NBM is vulnerable after severe head injury and that secondary insults play an important role in the damage. Thus, both neuronal perikarya and terminals of the basal forebrain cholinergic system are damaged after human fatal head injury. This damage may contribute to persisting dysfunction of memory and cognition in head-injured patients who survive.