Auditory Processing

Physical Dimension Perceptual Dimension

Amplitude Loudness

Frequency Pitch

Complexity Timbre

W. W. Norton

W. W. Norton

W. W. Norton

W. W. Norton

Mapping the Auditory System in Rhesus

Monkeys

University of Iowa

NeuroscienceProgram

The University of IowaDepartment of Psychology

Behavioral and Cognitive Neuroscience

Visual Processing Streams

25

“WHAT”

“WHERE”

24

Auditory cortexUnfolded view of

supratemporal plane and adjoining STG.

BeltParabelt

Core

Kaas and Hackett, PNAS 2000

Auditory Projection System

Lower Brainstem

Lower Brainstem

IC

MGB

IC

Early Auditory

Areas

MGB

Early Auditory

Areas

Auditory Projection System

Lower Brainstem

Lower Brainstem

IC

MGB

IC

Early Auditory

Areas

MGB

Early Auditory

Areas

Corpus Callosum,Anterior & Posterior

Commissures

Tectal Commissures

Lower Brainstem

Lower Brainstem

MGB

Early Auditory

Areas

MGB

Early Auditory

AreasForebrain Comm.

Tectal Comm. ICIC

Intact side 'Deaf' side

Methods

Speakers 2-DG injected intravenously

Monkey listens passively for 45 min

Wide variety of acoustic stimuli

Brain prepared for autoradiography

LCGU measured in ROIs throughout brain

ROIs compared for hemispheric asymmetries

Three surgically prepared monkeys

Auditory StimuliPassive Listening

BIRDS (10%)

ENVIRONMENTAL (18%)

HUMAN (9%)

MONKEYS (31%)

MUSIC (12%)

OTHER ANIMALS (8%)

TONES, SWEEPS, NOISE (12%)

29

2 DG in Intact (left) and Deafferented (right) Hemisphere

Early auditory areas

MGB

IC

A15

“Hearing” “Deaf”

30

31 Poremba et al., Science, 2003

Columns of 2DG activation in rSTG

Hearing Side of Deafferented Monkey

Completely Intact Monkey

32 Poremba et al., Science, 2003

Metabolic Mapping of Visual Cortex

Metabolic Mapping of Auditory Cortex

Overlap of Auditory and Visual Maps

Similar Auditory and Visual Processing Streams

57

“What”

“Where”

35

Left Hemisphere Right Hemisphere

Superior Temporal Gyrus (STG)(n=7 monkeys)

12

34

5

% o

f W

ho

le B

rain

Act

ivit

y

Monkey Vocalizations

Complex Sounds and Vocalizations

Complex Sounds No Vocalizations

Ambient Background Sound

70

80

90

100

110

120

130

Human Vocalizations

High

Low

High

Low

Monkey Vocalizations

p<0.001

*

Complex Sounds and

Vocalizations

p<0.01

*

FDG Activity in the Dorsal Temporal Pole

70

80

90

100

Ambient Background

Noise

% o

f W

ho

le B

rain

Ac

tivi

ty

Left Hemisphere Right Hemisphere

Monkey Vocalizations

p<0.001

*

Complex Sounds and

Vocalizations

p<0.01

*

FDG Activity in the Dorsal Temporal Pole

70

80

90

100

Ambient Background

Noise

Left Hemisphere Right Hemisphere

Complex Sounds No Vocalizations

% o

f W

ho

le B

rain

Ac

tivi

ty

70

80

90

100

Ambient Background Sound

Monkey Vocalizations

% o

f W

ho

le B

rain

Ac

tivi

ty

p < 0.001

*

MonkeyVocalizations

Split BrainMonkeys

Left Hemisphere Right Hemisphere

Dorsal Temporal Pole (n=8 intact monkeys, n=3 split brain monkeys)

44 Poremba et al., Nature, 2004

Similar Auditory and Visual Processing Streams

57

“What”

“Where”

Parabelt projections to prefrontal cortex

Romanski et al., Nature Neuroscience, 1999