Spinal Mechanisms for Sensorimotor Integration
We introduce Module 2: “Spinal Mechanisms for Sensorimotor Integration” with a counterintuitive notion, namely that the brain evolved, not to think or feel, but to control movement. We explore the functional organization of the somatosensory system, which underlies our sense of touch and proprioception, and we define the lines of communication from peripheral receptors in our skin, joints and muscles to somatosensory areas in cerebral cortices. Sense of touch and proprioception are not only critical for controlling movement but they are fundamental to human existence in general. Touch orients us to our internal and external worlds by providing the interface through which we experience what we are sensing. Proprioceptive afferents are essential components of the simplest neural circuits that are capable of generating motor behavior: spinal reflex circuits.
Learning Objectives
After completing this module, you will be able to:
- Identify the gross anatomic structures of the spinal cord and explain their functions.
- Recognize major internal structures of the spinal cord and describe their functions.
- List the major modalities of somatosensation.
- Explain the three-neuron organization for somatic sensation.
- Describe the neural pathways of conscious and unconscious proprioception.
- Solve clinical problems by relating somatosensory disorders to plausible lesion sites.
- Outline the methods and stimuli for assessing somatic sensation.
- Articulate behavioral consequences of peripheral sensory neuronopathy.
- Describe the motor functions of the spinal cord.
- Discuss the importance of the motor unit in control of movement.
- Outline the functions of the major ascending and descending spinal tracts.
- Explain the role of muscle spindles in reflexive motor functions.
- Explain the physiology of basic spinal reflexes.
- Discuss motor neuron disease and motor deficits resulting from spinal cord lesions.
