Neurofibrillary tangle formation in the nucleus basalis of Meynert ipsilateral to a massive cerebral infarct.

Two cases of massive cerebral infarct in the territory of the middle cerebral artery on one side of the brain are presented, in which many (Patient 1) or several (Patient 2) neurofibrillary tangle-bearing neurons were observed in the nucleus basalis of Meynert (nbM), ipsilateral to the infarcts. Tangles were absent or rare in the opposite nbM or in other areas of the brain. Considering the widespread projection of nbM axons to the ipsilateral cerebral cortex, this suggests that formation of neurofibrillary tangles can occur as a retrograde reaction in nbM neurons secondary to massive, old cerebral infarction.