1. MEDS 371
Auditory system II:
hindbrain
Dr. Duck O. Kim

2. cat brain dissected showing auditory system
cochlear
nucleus
inferior
colliculus
auditory
cortex
Oliver
auditory nerve
cerebellum
medial
geniculate

3. tonotopic organization of CN
cat CN h
dorsal
anterior
DCN h
AVCN
CN: cochlear nucleus
DCN: dorsal CN
AVCN: anterovent. CN
PVCN: posterovent. CN
PVCN h
Arnesen & Osen, 1978

4. type I (95%) Kiang, 1975 1. spherical bushy cell; AVCN
2. stellate cell; VCN
3. globular bushy cell; AVCN
4. octopus cell; PVCN
5. fusiform cell; DCN
Kiang, 1975

5. cells in the cochlear nucleusSB S GB O F
PST histogram
spiral ganglion
neuron
type I (95%)
cells in the cochlear nucleus
Kiang, 1975

6. end bulbs of Held at bushy cells of the AVCN
Ryugo, 1999, Fig-10

7. intracellular recording
intrinsic properties
EPSPs
cochlear nucleus
neurons
intracellular recording
in brain-slice
preparation
Oertel et al., 1988

8. The "where-processing" of sound:
Neural representation of auditory space
requires de novo computation
unlike the retinotopic map.

9. head-related impulse responses & transfer functions of rabbit
Kim, Bishop, Kuwada, 2010

10. Sound localization cues
* interaural time difference (ITD)
5 μsec; ~ 1 deg azimuth.
* interaural level difference (ILD)
* spectral cues
* direct/reverberant energy ratio; distance
virtual auditory space

11. the ascending auditory pathways of the cat binaural & monaural
pons
midbrain
thalamus
cortex
CN & SOC
the ascending
auditory pathways
of the cat
binaural &
monaural
pathways
Brodal, 1981

12. mso: medial sup. olive; lso: lateral sup. olive
Brodal Fig 9-8
mso: medial sup. olive; lso: lateral sup. olive
ntb: nuc. trazepoid body; ic: inf. coll.

13. cat superior olivary complex
MSO
LSO
MNTB
MSO
LSO
MNTB D M
(somata & dendrites)
(axons & endings)
Tsuchitani, 1978, Fig. 10

14. ILD processing in LSO
Purves Fig 13-14A

15. ILD processing in LSO
Purves Fig 13-14B

16. model for ITD coding employing
neural delay lines & coincidence detectors
MSO neurons act as
coincidence detectors.
best ITD 1 = 0 ms; sound in front
best ITD 2 = 50 ms
best ITD 3 = 100 ms
...
best ITD 7 = 700 ms;
sound on opposite side
maximum firing when
left (acoustic delay + neural delay) =
right (acoustic delay + neural delay)
Jeffress, 1948; Kuwada

17. head-related impulse responses & transfer functions of rabbit
Kim, Bishop, Kuwada, 2010

18. Inferior colliculus neurons show azimuth tuning.
10 dB
30 dB
50 dB
Kuwada, Bishop, Alex, Condit, Kim, 2011, J. Neurophys.

19. Sup. coll. contains visual and auditory space maps.
somatosen.
inputs
Purves Box 20B

20. the descending auditory pathways of the cat cortex thalamus midbrain
pons
CN & SOC
midbrain
thalamus
cortex
the descending
auditory pathways
of the cat
Brodal, 1981

21. olivocochlear neurons
LOC:
lateral
olivocochlear
MOC:
medial
Warr et al., 2002

22. * * inner hair cell outer hair cell afferent afferent Smith, 1975
efferent
nerve
fibers
ending *
afferent
efferent
nerve
ending
fibers
Smith, 1975