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Central Auditory Pathways

Terms in this set (14)

CN VIII and Central Auditory Pathways play several essential roles (3)
1. Provide auditory input essential to learning spoken language
2. Provides environmental info important to survival and quality of life
3. Provides auditory info essential for everyday communication
3 divisions of auditory receptor
outer, middle, and inner ear
- Includes pinna, external canal, and tympanic membrane
- Role is to channel sound vibrations to middle ear
outer ear (auditory receptor)
- Air-filled cavity with 3 bones (called ossicles)
- Role is to convert sound vibrations into mechanical energy
middle ear (auditory receptor)
- Fluid-filled, snail-shaped tube (called the cochlea)
- Role is to convert mechanical energy of moving ossicles into neural signal
· Cochlea maintains component frequencies of original sound input (called tonotopic representation)
inner ear (auditory receptor)
where are the cell bodies of the CN VIII auditory nerve located?
spiral ganglia of cochlea
· convey neural signal to CNS for processing beginning with brainstem

· Distance from cochlea to brainstem attachment is 19mm (or ¼")
· enters brainstem at pons-medulla junction
CN VIII auditory nerve role
5 stops of central auditory pathway
1. Cochlear nucleus
2. Superior olivary complex
3. Inferior colliculus
4. Medial geniculate body
5. Primary auditory cortex
o located at pons-medulla juncture, receives input from CN VIII
o Right and left convey auditory input to both sides of brainstem nuclei
cochlear nucleus (CN)
o first relay center located in pons, receives input from both cochlear nuclei
o role is to encode for time and intensity difference between each cochlea input (to determine what direction the sound is coming from)
Superior olivary complex (SOC)
provides pathway from SOC to inferior colliculus (IC)
lateral lemniscus
o located in midbrain, receives input from SOC (also receives input from both cochlear nuclei)
o encodes for advanced sound localization (reaction) - equivalent to 3D auditory space map
o Function: Orient head toward unexpected sound source via tectospinal tract
- May also be important for ensuring speech sounds are highlighted from other environmental sounds
inferior colliculus (IC)
o part of thalamus, receives input from IC
o final relay center, conveys auditory info to primary auditory cortex via internal capsule
Medial geniculate body (MGB)
o located on transverse temporal gyrus (also "Heschel's gyrus)
o Retains tonotopic representation originally encoded by cochlea
o Begins to recognize input as human speech, but unable to decode its meaning
- Interpretation of human speech begins in neighboring regions of secondary auditory cortex and Wernicke's area
Primary auditory cortex (A1)
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