CNBH, PDN, University of Cambridge
Part II: Lent Term 2015: ( 4 of 4)
Central Auditory Processing
Roy Patterson
Centre for the Neural Basis of Hearing
Department of Physiology, Development and Neuroscience
University of Cambridge
email rdp1@cam.ac.uk
Lecture slides on CamTools
https://camtools.cam.ac.uk/portal.html
Lecture slides, sounds and background papers on
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/
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Contents/Progress
Act I: Communication sounds and the information in
these sounds: message, Ss and Sf
Act II: Behavioural evidence for the role of these different forms
of information in the perception of communication
sounds
Act III: The processing of communication sounds in the early
stages of the auditory system, and hypotheses about
the representation of communication sounds in later
stages of the auditory pathway
Act IV: Brain imaging evidence concerning the representation
of communication sounds in auditory cortex
CNBH, PDN, University of Cambridge
We have discussed a model of auditory perception that
describes how sounds might be processed and represented at a
sequence of stages in auditory system.
All of the stages are mandatory and the order is crucial.
One representation is intended to simulate your initial Auditory
Image of the incoming sound and it is central to the model.
Sensations like pitch and loudness are summary statistics calculated from the
auditory image after it has been constructed.
Speech and music perception are thought to be based on the patterns that
arise in the auditory image.
So, this Auditory Image Model (AIM) predicts that we
should find a hierarchy of processing modules in the
auditory pathway.
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There is a sequence of neural centres in the auditory pathway.
Overviewhierarchy.
2
It looks like it could be a processing
The centres are separated by distances that are large relative the
resolution of functional brain imaging (fMRI).
LL
LL
The correspondence between the perceptual model and the anatomy suggests
that
(1) AIM could be useful when designing brain imaging studies of the
auditory system
and
(2) the brain imaging data could help us locate the auditory image.
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Basilar membrane motion in the cochlea
Anatomy of the Auditory Pathway: 1
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Neural activity pattern in the cochlear nucleus
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Strobed temporal integration in the inferior colliculus?
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The initial auditory image in the MGB??
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Auditory Image
The normalized auditory image in primary auditory cortex???
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The Auditory Image Model describes how the auditory system
separates pulse-resonance sounds from noise, and how it
normalizes and segregates the information about the pulse-rate
(Ss) and the resonance scale (Sf ) from the message.
So the brain imaging research focuses on finding evidence that the
neural centres in the auditory pathway are involved in source
segregation and normalization, and that the segregation and pulserate normalization come before the resonance scale normalization.
Moreover, speech-specific analysis and music-specific
analysis should occur in neural centres beyond, but not
too far from, those associated with segregation of pulseresonance sounds from noise and their normalization.
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Brain Imaging with Simple Contrasts
Find two sounds that differ only in the
perceptual property of interest (like pitch).
Scan the brain while people are listening, first to
one sound and then to the other sound.
Compare the brain activity produced by the two
sounds looking for places where one sound
produces more activity than the other.
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Brain imaging with Regular Interval Noise
Copy a sample of random noise; delay it by N ms;
add it to the original noise.
The process emphasises time intervals of N ms in the sound
and we hear a weak tone in the noise.
As you repeat the delay and add process, the relative strength
of the tonal component of the sound increases.
RIN makes a good imaging stimulus because the sounds have
similar distributions of energy over time and frequency.
In the experiment the RIN had 8 iterations of the
delay and add process.
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A B
Auditory Image
Noise
D
F
RIN
J
G
Neural activity patterns
of Noise and RIN
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B
C
E
G
H
K
Initial auditory images of
noise and RIN
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Continuous Imaging vs Sparse Imaging
continuous imaging
sparse imaging
haemodynamic response to test stimulus
haemodynamic response to scanner noise
Difference in sensitivity to stimulus: positive
negative
[original figure by D. Hall, IHR, Nottingham]
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Imaging pitch and melody in the brain
On a given scan, the listener is presented a sound
with a pulsing rhythm.
The sound has
no pitch (a noise),
a fixed pitch (boring melody)
or changing pitch (proper melody).
Asked to listen for pattern in the sound,
but no response is required.
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/PUJG02.pdf
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CN
T value
IC
CN
Parasagital view
showing CN/ IC
AC
AC
IC
Axial view
at level CN
AC
AC
MGB
40
35
30
25
20
15
10
5
0
CN
Coronal view showing IC Coronal view showing MGB
+ superior temporal lobe + superior temporal lobe
Griffiths et al. Nature Neuroscience (2001)
Sound minus silence contrast
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Left Hemisphere
axial
coronal
Group Analysis
noise-silence
fixed-noise
diatonic-fixed
random-fixed
structural
-78
-10
34.4°
axial
saggital
structural
coronal
10
78
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
saggital
Right Hemisphere
x
34.4°
Figure 2
saggital
axial
coronal
Group analysis
noise-silence
fixed-noise
tonic-fixed
random-fixed
structural
axial
saggital
structural
coronal
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
CNBH, PDN, University of Cambridge
x
-78
-10
34.4°
10
78
34.4°
regular
strong pitch
equal
energy
click trains
Neural Activity Pattern
Auditory Image
irregular
no pitch
Gutschalk, Patterson, Scherg, Uppenkamp, and Rupp, (2002)
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CNBH, PDN, University of Cambridge
posterior source: PT
Effects of
regularity
and
intensity
in MEG
effect of regularity in anterior source
effect of level in posterior source
Gutschalk, Patterson, Scherg, Uppenkamp, and Rupp, (2002)
anterior source: HG
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Conjecture
Conjecture
Conjecture
Proposed functional organisation of auditory cortex
all sounds primary auditory cortex
auditory cortex
tonal sounds
loudness
lively pitch
fixed pitch
lively pitch
CNBH, PDN, University of Cambridge
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/PUJG02.pdf
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/GPRUS02.pdf
Where does the auditory system segregate
the information associated with Ss, Sf
and the message?
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A damped sinusoid (12-ms period)
pulse
ringing
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Auditory image of a damped sinusoid
6000 Hz
pulse
1000 Hz
ringing
100 Hz
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Stimuli for Phonology Study
formant frequencies
regular
irregular
regular
onset timing
irregular
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Comparison
of speech and
music regions
z = 4mm
z = 4mm
mpmr-silence
nvdvpv-mpmr
mpmr-nvdvpv
noise-silence
fixed-noise
lively-fixed
y = -24mm
y = -17mm
z = -5mm
z = -5mm
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Left Hemisphere
saggital
Right Hemisphere
axial
saggital
axial
pitch
vtl
AudIm
coronal
phonology
Group analysis
noise-silence
fixed-noise
tonic-fixed
random-fixed
structural
coronalphonology
structural
x
-78
-10
34.4°
10
78
34.4°
CNBH, PDN, University of Cambridge
Conjecture
Conjecture
Conjecture
Proposed functional organisation of auditory cortex
all sounds primary auditory cortex
auditory cortex
tonal sounds
loudness
lively pitch
fixed pitch
receptive phonology
lively pitch
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Done!
Act I: the information in communication sounds
(animal calls, speech, musical notes)
Act II: the perception of communication sounds
(the robustness of perception)
Act III: the processing of communication sounds in the
auditory system (signal processing)
Act IV: the processing of communication sounds
(anatomy, physiology, brain imaging)
CNBH, PDN, University of Cambridge
End of Act IV
Thank you
Patterson, R.D., Uppenkamp, S., Johnsrude, I. and Griffiths, T. D. (2002). The
processing of temporal pitch and melody information in auditory
cortex. Neuron 36 767-776.
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/PUJG02.pdf
Gutschalk, A., Patterson, R.D., Rupp, A., Uppenkamp, S. and Scherg, M.
(2002). Sustained magnetic fields reveal separate sites for sound level and
temporal regularity in human auditory cortex. NeuroImage 15 207-216.
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/GPRUS02.pdf
Kriegstein, K. Von, Smith, D. R. R., Patterson, R. D., Kiebel, S. J. and
Griffiths, T. D. (2010). “How the human brain recognizes speech in the
context of changing speakers,”J. Neuroscience 30(2) 629–638.
http://www.pdn.cam.ac.uk/groups/cnbh/teaching/lectures/KSPKGjn2010.pdf
CNBH, PDN, University of Cambridge
Cast list
Roy Patterson, David Smith, Tim Ives, Ralph van Dinther
Centre for the Neural Basis of Hearing,
Physiology Department, University of Cambridge
fMRI in Cambridge: Ingrid Johnsrude, Dennis Norris, Matt
Davis, Alexis Hervais-Adelman, William Marslen-Wilson
MRC Cognition and Brain Sciences Unit,
15 Chaucer Road, Cambridge
MEG in Heidelberg: Andre Rupp, Alexander Gutschalk,
Stefan Uppenkamp, Michael Scherg
MEG in Muenster: Katrin Krumbholz, Annemarie
Preisler, Bernd Lutkenhoner
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Activation of voiced vs whispered speech
x=+51
signal change (%)
***
L
***
***
TE1.2
TE1.1
y=-2
voiced > whispered
whispered > voiced
GPR varies > VTL varies
voiced > silence
whispered > silence
CNBH, PDN, University of Cambridge
coronal
Group analysis
noise-silence
fixed-noise
tonic-fixed
random-fixed
Conjecture
axial
axial
structural
Conjecture
saggital
structural
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
Conjecture
saggital
coronal
x
-78
-10
34.4°
10
78
34.4°
CNBH, PDN, University of Cambridge
coronal
Group analysis
noise-silence
fixed-noise
tonic-fixed
random-fixed
Conjecture
axial
axial
structural
Conjecture
saggital
structural
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
Conjecture
saggital
coronal
x
-78
-10
34.4°
10
78
34.4°