In this chapter you will learn
 

• How the brain gets information about the body and the objects in contact with it
• What causes pain and ways it can be relieved
• How several brain structures work together to produce movement
• What some of the movement disorders are and how they impair movement

This chapter continues the theme of sensation presented in the previous chapters, this time by talking about the sensations and perceptions of the body.  The chapter begins with a case study of a woman who lost sensation of her body, which impaired her ability to walk or even sit upright.  This leads into a discussion of proprioception and how the skin receptors receive sensory input.  The vestibular sense, which is responsible for tracking the movement and orientation of the head, is then discussed. Next, the cortical areas responsible for body sensation are examined, with emphasis on the relative representation of body parts in the somatosensory cortex. Interestingly, somatosensory receptors exhibit the same center-surround characteristics as visual receptors. Then, the sensation of pain, or nociception, is examined with respect to the detection of pain and the resulting adaptations and endogenous chemicals that alleviate pain. A discussion of phantom pain includes an Application describing  treatments for the problem. Then, the control of movement is discussed, beginning with the muscles and spinal cord control through reflexes and central pattern generators. The discussion the proceeds to the planning and execution of movement, describing the roles of the prefrontal cortex, primary and secondary motor areas, basal ganglia and cerebellum.  The chapter concludes with a detailed discussion of movement disorders including Parkinson’s disease, Huntington’s disease, and autoimmune diseases (such as multiple sclerosis).  Two new In The News segments discuss cutting-edge procedures to control artificial limbs through direct commands by the brain, and drug compound screening for novel Parkinson’s Disease drugs. Current and future therapies for these diseases are also mentioned.