The final debate of the meeting centered on the question of the cause of neuronal cell death in Alzheimer’s disease. Plaques may come and go (if the vaccine data are correct) and neurofibrillary tangles may be important features of Alzheimer’s disease brain pathology, but most would agree that the root cause of the clinical dementia is the atrophy and loss of large numbers of neurons in specific regions associated with the loss of function. It follows that a full understanding of Alzheimer’s disease will have to include a cell biological description of the processes that link the plaque and tangle pathology to the neuronal cell death. As of this writing we know relatively little about this important link. Amyloid is toxic to neurons in vitro; transgenic mice that make too much Aβ have brain plaques and occasionally neuronal cell death; tau transgenic mice have tangle-like pathology in brain; and yet we do not know how the nerve cell responds to these amyloid–or tau–related insults or why the response leads to cell death.