Parkinson’s disease: affection of brain stem nuclei controlling premotor and motor neurons of the somatomotor system

Pathological changes which consistently develop in the lower brain stem of patients suffering from Parkinson’s disease are described against the background of the internal organization and interconnections of the involved nuclei, i.e., the gigantocellular reticular nucleus, bulbar raphe nuclei, and coeruleus-subcoeruleus area. Immunoreactions against the presynaptic protein α-synuclein reveal not only the voluminous forms of Lewy bodies and Lewy neurites but also the otherwise inconspicuous dot- or thread-like types. These lesions develop solely in specific neuronal types. Lipofuscin- or neuromelanin-laden projection cells which at the same time generate a long, unmyelinated or sparsely myelinated axon are particularly susceptible to developing the changes. The bulbar nuclei under consideration receive strong input from supramedullary sources, above all from higher order centers of the limbic system such as the central amygdalar nucleus, periaqueductal gray, and parabrachial nuclei. In turn, they generate descending projections to premotor and motor neurons of the somatomotor system. The disease-related deterioration of both the supramedullary limbic centers and the bulbar brain stem nuclei reduces the limbic influence and markedly impairs the control of premotor and motor neurons. This functional deficit most probably contributes to the overall dysfunction of the motor system typically evolving in the course of Parkinson’s disease.

Authors and Affiliations

1. Department of Anatomy, J. W. Goethe-University, Theodor Stern Kai 7, D-60590 Frankfurt, Germany e-mail: Braak@em.uni-frankfurt.de, Tel.: +49-69-63016900, Fax: +49-69-63016425, , , , , , DE

   H. Braak, U. Rüb, D. Sandmann-Keil, K. Arai & E. Braak

2. Department of Physiology, Flinders Medical Center Bedford Park, SA 5042 Australia, , , , , , AU

   W. P. Gai

3. Department of Neurology MST Hospital Group and Laboratorium Pathologie Oost Nederland, Burg. Edo Bergsmalaan, 7512 AD Enschede, The Netherlands, , , , , , NL

   R. A. I. de Vos & E. N. H. Jansen Steur

Received: 7 July 1999 / Revised: 30 August 1999 / Accepted: 6 September 1999

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