CORTICAL DISTRIBUTION OF NEUROFIBRILLARY TANGLES IN ALZHEIMERS-DISEASE MATCHES THE PATTERN OF NEURONS THAT RETAIN THEIR CAPACITY OF PLASTICREMODELING IN THE ADULT BRAIN

The formation of neurofibrillary tangles in Alzheimer's disease shows a preferential involvement of certain cytoarchitecturally defined cort ical areas suggesting systematic differences in regional neuronal vuln erability. The cellular and molecular nature of this selective neurona l vulnerability that follows a certain hierarchy of structural brain o rganization is largely unknown. In the present study, we compared the regional pattern of tangle density in Alzheimer's disease with systema tic regional differences in neuronal plasticity that can be observed b oth during ageing and in Alzheimer's disease. Changes in dendritic len gth and arborization of Golgi-impregnated pyramidal neurons were analy sed after three-dimensional reconstruction in 12 cortical areas. The i ntensity of dendritic remodelling that was observed during ageing as w ell as in Alzheimer's disease was regionally different and decreased i n the following order: transentorhinal region >limbic areas (entorhina l region, hippocampus)>non-primary association areas (37, 40, 46)>prim ary sensory association areas (7, 18, 22)>primary sensory and motor co rtex (17, 41, 4). These regional differences of neuronal plasticity fo llow the same pattern as the regional vulnerability to tangle formatio n in Alzheimer's disease. The results of the present study provide evi dence that a high degree of structural neuronal plasticity might predi spose neurons to tangle formation. (C) 1998 IBRO. Published by Elsevie r Science Ltd.