Auditory Pathways Flashcards
1
Q
outline the auditory pathway
A
- Information travels from the receptors in the organ of Corti of the inner ear to the CNS, carried by the cochlear nerve (CNVIII).
- The lateral lemniscus carries sound information from cochlear nucleus to various brainstem nuclei, and eventually the inferior colliculus of the midbrain.
- This pathway ultimately reaches the primary auditory cortex in the superior temporal gyrus for conscious perception.
2
Q
lemniscal and non lemniscal pathway
A
- Primary (lemniscal) pathway: main pathway through which auditory information reaches the primary auditory cortex (A1)
- Non-lemniscal pathway: mediates unconscious perceptions, e.g. attention, emotional response and auditory reflexes
3
Q
primary pathway
A
- the spiral ganglion houses the bodies of the 1st order neurons, these receive information from hair cells in the organ of COrti
- their central axons form the cochlear nerve
- first order neurons synapse at the ipsilateral cochlear nuclei
4
Q
where does the vestibular nerve join the cochlear nerve
A
entering the internal acoustic meatus - CNVIII
5
Q
2nd order neurons
A
- superior to the coclear nuclei some fibres are crossed and some are not, so the input is essentially bilateral in each lateral lemniscus
- fibres ascend in the lateral lemniscus
- some decussate to the superior olivary nuclei before ascending to the lateral lemniscus
- all arrive at inferior colliculus
- these fibres project to ipsilateral medial geniculate body in the thalamus
6
Q
where is the primary auditory cortex (A1) located?
A
- superior temporal gyrus - right under the lateral fissure
7
Q
tonotopical organisation of the superior temporal gyrus
A
- lower f ends up in the anterolateral part
- higher f in the posteromedial part
8
Q
damage to Brocas area
A
- difficulty producing language
9
Q
damage to Wernicke’s area
A
- difficulty comprehending langauage
- eg says words out of order/meaningless
