Concept: The neuromotor system forms the foundation for the control of movement.
After completing this chapter you will be able to
Describe the general structure of a neuron and the types and functions of neurons
Identify and describe the structural components of the brain that are most directly involved in control of movement and describe their primary functions
Identify and describe the neural pathways that make up the ascending and descending tracts
Describe a motor unit, the recruitment of motor units, and their relationship to the control of movement
Describe the basic components of a conceptual hierarchical model that describes the CNS structures and their functions in the control of movement
When you are reading at your desk and want to write a few notes about what you are reading, you must undertake a sequence of coordinated movements to accomplish your goal. You must first pick up your pen and then position your head, body, arm, hand, and fingers so that you can use the pen. Then you must initiate the movements required to write the words you want to put on the paper. Although this example may seem to describe a relatively simple task that you can do very easily and quickly, have you ever thought about what is happening in your nervous system to allow you to carry out this sequence of events? As simple as the individual movements may be, a rather complex array of neural activity is associated with planning and performing the task. For example, your decision to pick up the pen was a cognitive activity, but what happened in the nervous system to change this cognitive act into a motor act? To answer this question, we need to consider two important issues in the study of motor control. One concerns the neurophysiologic basis of the neural activity associated with this sequence of events. The other is the more theoretical issue of how the cognitive intention to perform an action becomes a sequence of movements that enables a person to achieve the intended action goal. We will consider the first of these issues in this chapter by looking at the central nervous system in terms of its structure and function as related to the performance of motor skills. We will briefly consider the second issue from a neurological perspective but then address it in more detail in chapter 5, where we discuss theories of motor control.
You may be asking why understanding this process is necessary for someone who wants to pursue a professional career that essentially entails helping people learn or relearn motor skills or improve their performance of skills. The answer is that a basic understanding of the physiology underlying the control of voluntary movement establishes a more comprehensive appreciation and awareness of the capabilities and limitations of the people with whom a practitioner works. The person who plans to enter ...