Cerebral Networks of Speech Motor Control: fMRI Data

H. Ackermann, K. Mathiak, I. Hertrich,

W. Grodd, A. Riecker

Departments of Neurology and Neuroradiology,

University of Tübingen

5th International Conference onSpeech Motor ControlNijmegen, June 7 – 10, 2006

Cerebral Organization of Speech Motor Control: The Beginnings

Petersen et al. 1988, 1989 (PET study)but see Sidtis et al. 1999

Cerebral Organization of ….

Petersen et al. 1988, 1989, Posner & Raichle 21999

supplementary motor area (SMA)BL sensorimotor cortex LH insular cortexBL medial cerebellum

Wise et al. 1999: left anterior insula engaged in „articulatory planning“ (Dronkers 1996, but see Hillis et al. 2002)

P Indefrey, WJM Levelt. The spatial and temporal signatures of word production components. Cognition 2004;92:101-144

review of 82 imaging studies on word production

cerebral correlates / time course of the following successive stages of speech production:

lexical selection, phonological code retrieval, syllabification, self-monitoring, phonetic / articulatory processes (Levelt, Roelofs & Meyer 1999)

Indefrey & Levelt 2004

Cerebral Network of Phonetic /

Articulatory Processes

12 areas pertaining to the central-motor system:

R/L ventral motor and sensory regions, R dorsal motor region, R SMA, R/L cerebellum, R/L thalamus, R midbrain

5 areas not pertaining to the central-motor system,

e.g., orbitofrontal and occipitotemporal regions

Indefrey & Levelt 2004

Syllable Rate Control: fMRI Experiment I

figure

Riecker et al. 2005

normal subjects, overt (aloud) syllable repetitions (“pa”), 2.0 / 2.5 / 3.0 / 4.0 / 5.0 / 6.0 Hz, applied via earphones

Experiment I: Signal Analysis

1. Parametric approach:

1.1. hemodynamic main effects across all

repetition rates versus baseline

1.2. positive linear, negative linear andnonlinear rate / response

functions Büchel & Friston 1996,

1998

2. Connectivity analyses based upon time series of hemodynamic activation

Experiment I: Signal Analysis

1. Parametric approach:

1.1. hemodynamic main effects across all

repetition rates versus baseline

1.2. positive linear, negative linear andnonlinear rate / response

functions Büchel & Friston 1996,

1998

2. Connectivity analyses based upon time series of hemodynamic activation

Overt Syllable Repetitions IMain Effects

normal subjects

Riecker et al. 2005

Guenther et al. 2006

Experiment I: Signal Analysis

1. Parametric approach:

1.1. hemodynamic main effects across all

repetition rates versus baseline

1.2. positive linear, negative linear andnonlinear rate / response

functions Büchel & Friston 1996,

1998

2. Connectivity analyses based upon time series of hemodynamic activation

Overt Syllable Repetitions IIRate / Response Functions

Riecker et al. 2005

Overt Syllable Repetitions IIIGroup Averages

Riecker et al. 2005normal subjects

Insel links

0

2

4

6

1 2 3 4 5 6

Caudatum links

0

2

4

6

1 2 3 4 5 6

Putamen / Pallidum

0

2

4

6

1 2 3 4 5 6

Thalamus

0

2

4

6

1 2 3 4 5 6

JJ Sidtis, SC Strother, DA Rottenberg. Predicting performance from functional imaging data: Methods matter. NeuroImage 2003;20:615-624

question: can functional imaging data predict performance?

task: syllable repetitions as fast as possible

syllable rate = (- 3.55 * right caudate) + (2.51 * left inferior frontal) + 5.60

more efficient organization at higher rates (p.c.)

Rate Control / Basal Ganglia:

Brown 2003: Oscillatory nature of human basal

ganglia activity

Logigian et al. 1991: Tremor oscillations may pace

repetitive voluntary motor behaviour (finger

flexion / extension, oral diadochokinesis)

Possible control mechanism of syllable

repetitions: adjustment of inherent basal ganglia

oscillations to the pacing signal

Overt Syllable Repetitions IIIGroup Averages

Riecker et al. 2005

Cerebellum z=-24

0

2

4

6

1 2 3 4 5 6

Cerebellum z=-57

0

2

4

6

1 2 3 4 5 6

normal subjects

Syllable Rate Control: fMRI Experiment II

Hypothesis: differential contribution of basal ganglia and cerebellum to syllable rate control

Task: covert (silent) syllable repetitions, 2.5 / 4.0 / 5.5 Hz,

  paced via earphones

Design: block design (8 blocks, R/A, 10 meas)

Analysis: categorical and parametric (rate and time effects) analysis using SPM99

Wildgruber et al. 2001

Covert Syllable Repetitions: R/R-F

Wildgruber et al. 2001

Syllable Rate in Dysarthric SubjectsAcoustic Analyses

Ackermann et al. 1995

Review: Hertrich, Ackermann. Acoustic analysis of durational ... In: Lebrun Y (ed). From the Brain to the Mouth. Dordrecht 1997, 11-47Review: Ackermann, Mathiak, Ivry. Temporal organization of „internal speech” ... Behav Cogn Neurosci Rev 2004;3:14-22

Overt Syllable Repetitions IIIGroup Averages

Riecker et al. 2005normal subjects

Insel links

0

2

4

6

1 2 3 4 5 6

Caudatum links

0

2

4

6

1 2 3 4 5 6

Putamen / Pallidum

0

2

4

6

1 2 3 4 5 6

Thalamus

0

2

4

6

1 2 3 4 5 6

Finger Tapping TasksRate / Response Functions

Riecker et al. 2003normal subjects

Summary Part 1: Cerebral Rate Control

Convergence of clinical-behavioural findings and

functional imaging data:

Striatum: normal speaking rate / hastening

phenomenon - negative fMRI rate / response

functions

Cerebellum: reduced syllable rate (> 3 Hz) –

fMRI threshold effect at about 3 Hz

for a review see Ackermann & Hertrich 2000, Ackermann et al. 2004

Cerebellar Functions

Experiment I: Signal Analysis

1. Parametric approach:

1.1. hemodynamic main effects across all

repetition rates versus baseline

1.2. positive linear, negative linear andnonlinear rate / response

functions Büchel & Friston 1996,

1998

2. Connectivity analyses based upon time series of hemodynamic activation

Time course of

hemodynamic

activation

Riecker et al. 2005

time (s)

effectsize

Two Cerebral Networks of Speech Motor Control ???

bold lines: very high correlations (>0.9)

thin lines: high correlations (0.75-0.9)

Syllable Rate Control: fMRI Experiment II

Hypothesis: differential contribution of basal ganglia and cerebellum to syllable rate control

Task: covert (silent) syllable repetitions, 2.5 / 4.0 / 5.5 Hz,

  paced via earphones

Design: block design (8 blocks, R/A, 10 meas)

Analysis: categorical and parametric (rate and time effects) analysis using SPM99

Wildgruber et al. 2001

Covert production of fluent speech (highly overlearned word strings): Wildgruber et al. 1996, Ackermann et al. 1998, Riecker et al. 2000

Inner / Silent / Covert Speech

internal speech = “prearticulatory, but otherwise fully parsed speech code” (Levelt 1989)

“close functional equivalence between motor imagery and motor preparation” (Jeannerod 1994)

inner speech = “window” into articulatory planning processes (preceding movement execution)

but: Sokolov 1968, 1972

Covert Syllable Repetitions: R/R-F

Wildgruber et al. 2001LC: -21, -60, -24 / RC: 24, -57, -24

Guenther et al. 2006: DIVA model

effectsize

Two Cerebral Networks of Speech Motor Control ???

anterior insula / speech production: Ackermann & Riecker 2004

Hemodynamic activation of intrasylvian cortex

in association with

anticipation / application of painful stimuli,

spider phobia (sensitive to therapy),

swallowing & tactile stimulation of the tongue,

stress urinary incontinence (sensitive to therapy),

high-intensity emotional facial expressions,

aesthetic judgments of beauty,

olfactory functions.

NeuroImage, vol 29, no 1, January 1, 2006

Speech and Anterior Insula

Insular cortex part of the cerebral representation of the autonomic nervous system, e.g., cardiac functions or respiration, e.g., Harper et al. 2005

pre-setting of laryngeal and respiratory muscles

However, no insular activation during whistling, Dresel et al. 2005

for a review see Ackermann & Riecker 2004

Hemodynamic activation of intrasylvian cortex

in association with

anticipation / application of painful stimuli,

spider phobia (sensitive to therapy),

swallowing & tactile stimulation of the tongue,

stress urinary incontinence (sensitive to therapy),

high-intensity emotional facial expressions,

aesthetic judgments of beauty,

olfactory functions.

NeuroImage, vol 29, no 1, January 1, 2006

time (s)

effectsize

Insel links

0

2

4

6

1 2 3 4 5 6

Caudatum links

0

2

4

6

1 2 3 4 5 6

Putamen / Pallidum

0

2

4

6

1 2 3 4 5 6

Thalamus

0

2

4

6

1 2 3 4 5 6

Part 1: Rate / Response Functions ofHemodynamicActivation

Part 2:Time Course of Hemodynamic Activation

NEUROLOGIE Dirk Wildgruber

Axel RieckerIngo Hertrich Klaus Mathiak

Hermann Ackermann

Michael Erb Uwe Klose

Wolfgang Grodd

NEUROLOGY

NEURORADIOLOGY

Participants