ABSTRACT
This chapter reviews the anatomy of the auditory system. It describes the innervation of the cochlea. The chapter reviews the synaptic connections that the auditory system makes as it carries information into the brain. It then describes some of the changes in discriminative behavior that occur when certain of these pathways or structures are destroyed through ablation. The system of connections and elements within the cochlea rests on a very orderly arrangement of receptor elements. In the cochlea the hair cell itself is the primary receptor element. In the cat about 50,000 fibers enter the cochlea through the small openings in the basilar membrane called the habenula perforata. The traveling wave within cochlea and orderly arrangement of the receptor elements make it clear that a strong relation must hold between the frequency of the stimulating acoustic sinusoid and the place of the neural element. This principle is called tonotopic organization and it characterizes nuclei and tracts of the auditory system.
