ABSTRACT
This chapter provides a brief and necessarily simplified sketch of the main anatomical features of the ascending auditory pathway from cochlea to cortex in an attempt to provide a basis for further discussion of the role of its major structures in audition and speech. The inferior colliculus consists of a central nucleus and two cortical areas, an external cortex and a dorsal cortex. The external cortex of the inferior colliculus receives both auditory and somatosensory input, and projects to the medial division of the medial geniculate body. The medial geniculate body is connected reciprocally to the auditory cortex. It is a rounded projection on the ventrolateral surface of the thalamus. The cochlea itself is a coiled canal spiraling around a central axis or modiolus. Much of the physiological data that have been obtained on cochlear nuclear function have come from anaesthetized animals in which the effects of the inhibitory inputs may have been modified.
