Auditory pathway

Question 1

Auditory pathway

Answer 1

-how the electrical info from the cochlea is communicated to the brain, where its interpreted.
Sound goes into right or left ear and goes to both right and left hemispheres
-ipsilateral - signal stays on same side
-contralateral - signal crosses over (decussates) to other side

Question 2

Auditory pathway - peripheral neurons

Answer 2

1. hair cells throughout scala media pick up electrical energy and join together to go through spiral ganglia (bony core of cochlia (modiolus)).
2. cable of neurons exit cochlea through internal auditory meatus, then start trip up the brain
3. Once they enter central nervous system, called central neurons

Question 3

Auditory pathway - Central neurons

Answer 3

1. nerve enters central nervous system at brain stem in a slice called trapezoid body
2. first synapse takes place at dorsal or ventral cochlear nucleus. some fibers decussate to contralateral nuclei
3. fibers go to the superior olivary complex - catch elevator.
4. nerve fibers travel up to the midbrain, where they synapse and decussate at the inferior colliculus
5. fibers go to the hemisphere (no more decussating) to synapse in the medial geniculates and end in each hemispheres temporal lobe (Herschel’s gyrus)

Question 4

Theories of hearing

Answer 4

-Place theory - Stimulating basialiar membrane at base results in perception of high frequency sounds, closer to helicotrema results in perception of low frequency sounds.
-Frequency theory - Cochlea sends specific information to brain or does is send a quantitiative code of frequency of firings
PROBABLY A COMBO