PSYC 2P49 Lecture Notes - Lecture 12: Vestibulocochlear Nerve, Basilar Membrane, Tectorial Membrane
14 Dec 2016
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Document Summary
Population code: different nerves have different threshold. Basil membrane is displaced at the same rate of the source wave. But different parts of the membrane are displaced to different degrees by different frequencies. Also aided by the structure of the basilar membrane. Widens and becomes thinner at the end. High frequencies displace the rigid, narrow regions. Low frequencies displace the exible, wider regions. 90% of afferent bers (to the brain) come from one row of inner hair cells. Efferent signals (from the brain) help to enhance contrast between frequencies. Information about hair cell activity sent to the brain via the auditory nerve. Response of each ber corresponds to a particular location in the cochlea. Because pressure changes are occurring at a particular frequency, activation of auditory nerve cells tends to be phase locked (i. e. , re in phase with a particular frequency) Are more and less sensitive to sounds at different frequencies. Perceive them as more or less intense.
