Dysarthrias associated with extra-pyramidal syndromes

Abstract

The term ‘extra-pyramidal system’ was first used by Wilson (1912) to refer to those parts of the central nervous system concerned with motor function but which are not a part of the pyramidal system. The extra-pyramidal system, as described in Chapter 8, consists of a complex series of multi-synaptic pathways which indirectly connect the motor areas of the cerebral cortex to the level of the lower motor neurones. The major components of the extra-pyramidal system include the basal ganglia (see Chapter 3) within the cerebral hemispheres plus the various brainstem nuclei that contribute to motor functioning. These latter nuclei include the paired substantia nigra, the red nuclei and the sub-thalamic nuclei.