Introduction to Efferent Systems
Organisms must learn what representations in the world are important – that is, which sights, smells, and sounds indicate safety, food, or danger. Knowledge of what is and is not important is acquired by information arising from the sensory organs, and this knowledge is then acted upon by the motor system, expressed by approach or avoidance behavior. A loud “Hey you!” will evoke a strikingly different motor and autonomic response compared to that of a sultry “Hello, handsome.” Likewise, a patron can ignore the sounds inside a busy restaurant but not when his name is being called. Stimuli that have no immediate significance become relegated to “background noise” and can be disregarded. During our lifetimes, we learn about stimuli and stimulus context. The sound and sight of gunshots in the street are generally different from those experienced in a movie theater. Stimulus content and context are presumably processed in the cerebral hemispheres, where significance is established.
KeywordsHair Cell Auditory Nerve Fiber Interaural Level Difference Superior Olivary Complex Efferent System
The author was supported in part by NIH grants DC004395 and DC000232, a grant from Advanced Bionics Corporation, and a Life Science Research Award from the Office of Science and Medical Research, New South Wales, Australia.
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