PSL300H1 Lecture Notes - Lecture 14: Cochlear Nerve, Cochlea
Document Summary
Middle ear mechanics (cid:131) tympanum vibrates with sequence of sound pressure pulses (in air) (cid:131) lever system of ossicles amplifies pressure on tympanum 22-fold (cid:131) amplified pressure exerted on oval window of cochlea (filled with fluid) Hair cell amplifications (cid:131) hair cells contract when depolarized: amplifies basilar membrane displacement. Cochlear nuclei (cid:131) cochlear afferents project to the cochlear nuclei (in viiith cranial nerve) (cid:131) tonotopic organization neurons with a common preferred sound frequency (pitch) are grouped in order as in the cochlea. Inferior colliculus (cid:131) midbrain auditory center (cid:131) input from ipsilateral mso and contralateral lso: i. e. processes signals from contralateral sound sources (cid:131) integrates binaural intensity difference or delay across all frequency bands to compute consensus of sound location. Medial geniculate nucleus (mgn) (cid:131) auditory thalamic nucleus (cid:131) organizes information from inferior colliculus to be processed in the auditory cortex (cid:131) auditory information pertaining to communication (ex. language)
