BMS 870 Lecture Notes - Lecture 16: Motor Neuron, Temporal Lobe, Saccule
24 Dec 2017
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Document Summary
Afferents from spiral ganglion into brain stem in the auditory-vestibular nerve. At the lvl of medulla, axons innervate dorsal cochlear nucleus and ventral cochlear nucleus. Axon branches to synapse on neurons in both cochlear nuclei. Neural signals can travel from spiral ganglion to auditory cortex via numerous pathways: primary pathway: Ventral cochlear nucleus neurons send axons that project to superior olive on both sides of brain stem. Axons ascend in lateral lemniscus (collection of axons) and innervate inferior colliculus of midbrain. *all ascending auditory pathways converge at inferior colliculus. Inferior colliculus neurons send axons to medial geniculate nucleus of thalamus. Response properties of neurons in auditory pathway: input from neurons in spiral ganglion: Receive input from single inner hair cell = fire aps only in response to sound within a limited f range. Aps recorded from single auditory nerve fiber (i. e. axon of a spiral ganglion cell) = firing rate in response to sounds at different frequencies.
