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CNBH, PDN, University of Cambridge
Part II: Lent Term 2011: ( 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 and background papers Not on CamCors
www.pdn.cam.ac.uk/cnbh
Latest material on size information in hearing
www.AcousticScale.org
CNBH, PDN, University of Cambridge
Progress:
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
Overview 1
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.
CNBH, PDN, University of Cambridge
There is a sequence of neural centres in the auditory
could be a processing hierarchy,
pathway that looks like it Overview 2
and 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 that
(2) the brain imaging data could help us locate the all important auditory
image.
CNBH, PDN, University of Cambridge
Overview 3
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 pulse-
rate normalization come before the resonance scale normalization.
Moreover, speech-specific analysis and music-specific
analysis should occur in neural centres just beyond
those associated with segregation of pulse-resonance
sounds from noise and their normalization.
CNBH, PDN, University of Cambridge
Cast list
Roy Patterson, David Smith, Tim Ives, Alexis Hervais-
Adelman, Martin Vestergaard
Centre for the Neural Basis of Hearing,
Physiology Department, University of Cambridge
fMRI in Cambridge: Dennis Norris, Matt Davis, William
Marslen-Wilson, Friedemann Pulvermuller
MRC Cognition and Brain Sciences Unit,
15 Chaucer Road, Cambridge
MEG in Heidelberg: Andre Rupp, Alexander Gutschalk,
Stefan Uppenkamp, Michael Scherg
MEG in Muenster: Annemarie Preisler, Bernd
Lutkenhoner
IHR in Nottingham: Katrin Krumbholz, Nick
Clarke
CNBH, PDN, University of Cambridge
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
Part III a
Where does the auditory system segregate the
information associated with Ss, Sf and the message?
a) in the pathway up to primary auditory cortex
CNBH, PDN, University of Cambridge
Anatomy of the Auditory Pathway: 1
Basilar membrane motion
CNBH, PDN, University of Cambridge
Neural activity pattern
CNBH, PDN, University of Cambridge
Strobed temporal integration
CNBH, PDN, University of Cambridge
Auditory Image
CNBH, PDN, University of Cambridge
0 iterations A B C
no temporal regularity
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
Noise
no pitch
D E
8 iterations
F G H
temporal regularity
RIS
pitch
J K
CNBH, PDN, University of Cambridge
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]
CNBH, PDN, University of Cambridge
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.
CNBH, PDN, University of Cambridge
Sound minus silence contrast
CN
Griffiths et al. (2001)
IC T value
CN 40
35
Parasagital view Axial view 30
showing CN/ IC at level CN 25
20
15
AC AC AC AC 10
5
IC MGB
0
CN
Coronal view showing IC Coronal view showing MGB
+ superior temporal lobe + superior temporal lobe
CNBH, PDN, University of Cambridge
Part III b
Where does the auditory system segregate the
information associated with Ss, Sf and the message?
b) in auditory cortex and adjacent areas in the
temporal lobe.
CNBH, PDN, University of Cambridge
Left Hemisphere Right Hemisphere
saggital axial axial saggital
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
coronal structural structural coronal
x
Group Analysis -78 -10 10 78
noise-silence
fixed-noise
diatonic-fixed
random-fixed 34.4° 34.4°
Figure 2
CNBH, PDN, University of Cambridge
saggital axial axial saggital
Patterson, Uppenkamp, Johnsrude and Griffiths (2002)
coronal structural structural coronal
x
Group analysis -78 -10 10 78
noise-silence
fixed-noise
tonic-fixed
random-fixed 34.4° 34.4°
CNBH, PDN, University of Cambridge
Gutschalk, Patterson, Scherg, Uppenkamp, and Rupp, (2002)
regular
strong pitch
equal
Neural Activity Pattern Auditory Image
energy
click trains
irregular
no pitch
CNBH, PDN, University of Cambridge
anterior source: HG posterior source: PT
Effects of
Gutschalk, Patterson, Scherg, Uppenkamp, and Rupp, (2002)
regularity
and
intensity
in MEG
effect of regularity in anterior source effect of level in posterior source
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
lively pitch
CNBH, PDN, University of Cambridge
Stabilised auditory image of the /ae/ in ‘hat’: 2
glottal pulses formants
Patterson et al. (1995)
Tonotopic axis of cochlea
Patterson (1994b)
pitch
CNBH, PDN, University of Cambridge
A damped sinusoid (12-ms period)
pulse
ringing
CNBH, PDN, University of Cambridge
Auditory image of a damped sinusoid
6000 Hz
pulse
1000 Hz
ringing
100 Hz
CNBH, PDN, University of Cambridge
Stimuli for Phonology Study
onset timing
regular irregular
regular
formant frequencies
irregular
CNBH, PDN, University of Cambridge
Comparison
of speech and
music regions
z = 4mm z = 4mm
mpmr-silence noise-silence
nvdvpv-mpmr fixed-noise
mpmr-nvdvpv lively-fixed
y = -24mm y = -17mm
z = -5mm z = -5mm
CNBH, PDN, University of Cambridge
Left Hemisphere Right Hemisphere
saggital axial axial saggital
pitch
vtl
AudIm
coronal
phonology structural structural phonology
coronal
x
Group analysis -78 -10 10 78
noise-silence
fixed-noise
tonic-fixed
random-fixed 34.4° 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
receptive phonology
fixed pitch
lively pitch
CNBH, PDN, University of Cambridge
Progress: 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)
