MODULE 3 - INTRODUCTION

     

     We begin our study of somatosensory systems by considering the pathway that conveys discriminative touch and proprioceptive information from the body to the cerebral cortex. While this module focuses on the anatomy of the pathway, it will be essential for you to become familiar with the functional characteristics of the neurons that are involved. To do so, you will want to spend some time with the references cited below. There are three issues to explore:

     1) The array of sensory receptors present in the skin and how they are distributed over the surface of the body. Suggestion - read UTex, Section 2, Chapt 2, and scroll to 2.4.

     2) How these receptors convert mechanical stimuli into a neural code. Suggestion - read UTex, Section 2, Chapt 2, and scroll to 2.2.

     3) The relationship between the diameter of peripheral axons, the speed with which they conduct action potentials, and the kind of sensory information they convey. Suggestion - read UTex, Section 2, Chapt 4 , and scroll to 2.2 and Table I.

     If you have time, read ALL of Chapt 2 and 4.1 - 4.6 of Chapt 4

      Be aware that the topic of this Module, the Dorsal Column-Medial Lemniscus pathwayDC-ML) is often termed the Posterior Column-Medial Lemniscus pathway (PC-ML). It is an open question whether to use the terms "anterior-posterior" or "dorsal-ventral" when describing spinal cord structures.