Download - Temporal processing 2
![Page 1: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/1.jpg)
Temporal processing 2
Mechanisms responsible for developmental changes in temporal
processing
![Page 2: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/2.jpg)
What needs explaining? Immature performance in some temporal
processing tasks as late as 11 years. More certainly, immature temporal
processing in infants younger than 6 months old.
![Page 3: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/3.jpg)
Neural representation of temporal characteristics of sound
![Page 4: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/4.jpg)
Development of phase locking
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Phase locking takes longer to develop than frequency tuning.
Phase locking develops in the central nervous system later than at the periphery.
![Page 5: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/5.jpg)
Development of phase-locking in human infants
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 6: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/6.jpg)
Evoked potentials as measures of phase locking and synchronous transmission
![Page 7: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/7.jpg)
ABR waveform development
![Page 8: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/8.jpg)
Cortical potential waveform development
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 9: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/9.jpg)
Evoked potential latency development as a measure of temporal processing
![Page 10: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/10.jpg)
ABR latency development
B BB B B
B
33-34 35-36 37-38 39-40 41-42 43-441.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
Conceptional age (wk)
![Page 11: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/11.jpg)
ABR latency development
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 12: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/12.jpg)
ABR latency development
![Page 13: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/13.jpg)
ABR latency development
![Page 14: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/14.jpg)
Cortical potential latency development
![Page 15: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/15.jpg)
Possible anatomical correlates Myelination Other aspects of neural transmission
Axonal, dendritic maturation Synaptic development
![Page 16: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/16.jpg)
Timing of different aspects of neural structural development
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 17: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/17.jpg)
Development of myelination Appears in auditory nerve and brainstem
around 29 weeks gestational age Auditory nerve and brainstem
indistinguishable form adult by 1 year postnatal age
Begins prenatally in projection to thalamus, but colliculus-thalamus and thalamus-cortex take longer to reach adult stage.
![Page 18: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/18.jpg)
Dendritic development
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Qu
ickTim
e™
an
d a
TIF
F (U
ncom
pre
ssed) d
eco
mp
resso
rare
nee
de
d to
see
this p
ictu
re.
1 mo
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
6 mo
![Page 19: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/19.jpg)
Organization of auditory cortex
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 20: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/20.jpg)
Axonal development in auditory cortex
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 21: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/21.jpg)
Myelination and synaptic transmission contribute to development of ABR latency
![Page 22: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/22.jpg)
Model of ABR generation
![Page 23: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/23.jpg)
Myelination and synaptic transmission contribute to development of ABR latency
![Page 24: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/24.jpg)
Conclusions: development of phase locking Phase locking and neural synchrony
develop over a long time course. The auditory nerve and brainstem appear
to be mature in this regard earlier than other parts of the auditory nervous system.
Maturation of phase locking could be related to the development of some sorts of temporal processing.
![Page 25: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/25.jpg)
Complications imposed by adaptation
![Page 26: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/26.jpg)
Susceptibility to adaptation in immature neurons
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
![Page 27: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/27.jpg)
Evoked potential measures of adaptation Rate effects Forward masking
![Page 28: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/28.jpg)
Rate effects in human infants: Wave I
![Page 29: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/29.jpg)
Rate effects in human infants: Wave V
![Page 30: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/30.jpg)
Comparison of ABR waves on rate effect
![Page 31: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/31.jpg)
ABR interpeak interval rate effect
B
BB B B B
JJ
JJ J J
1 month 3 mo 6-12 mo 1-3 yr 4-6 yr adults0
0.2
0.4
0.6
0.8
1
1.2
Age
B 50-10/sec
J 90-10/sec
![Page 32: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/32.jpg)
Forward masking with ABR
![Page 33: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/33.jpg)
ABR susceptibility to forward masking
Adults Newborns0
10
20
30
40
50
60
70 Forward masked
Slow rate unmasked
![Page 34: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/34.jpg)
Conclusions: development of adaptation Before perhaps 3 months of age, infants
appear to be particularly susceptible to adaptation at the level of the brainstem.
This could explain infants’ susceptibility to forward masking at this age.
![Page 35: Temporal processing 2](https://reader035.vdocuments.us/reader035/viewer/2022062520/568158ca550346895dc613ca/html5/thumbnails/35.jpg)
Conclusions: Mechanisms underlying development of temporal processing
Both phase locking and adaptation mature during infancy, at least at the level of the brainstem.
Low level neural immaturity may contribute to some immaturity in temporal processing.
Low level neural immaturity cannot explain infants’ poor gap detection performance, however.