MODULE 5

INTRODUCTION

From a clinical point of view, this may be the most important topic we take up in this sequence of Neuroscience labs. While Kingsley's diagrams and descriptions of the various pathways are good, he gives more detail than you need to know, and some of the names he uses are at odds with those in common usage. So, rather than follow the book, we will base our treatment on the model proposed by Lawrence and Kuypers and shown in FIGURE 5-1. Your job is to trace three pathways that descend in parallel from the cerebral cortex to the spinal cord. They are the corticospinal (pyramidal) tract (FIGURE 5-2), the cortico-rubro-spinal pathway (FIGURE 5-3 ), and the cortico-reticulo-spinal pathway (FIGURE 5-4 ). In addition, you will identify the corticobulbar pathway, the homologue of the corticospinal tract, but providing input to the motor nuclei of the brainstem (FIGURE 5-5 ). You will also look at three tracts that originate at the brainstem level and descend in the spinal cord - the two vestibulospinal (FIGURE 5-6)tracts and the tectospinal tract (FIGURE 5-7)

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