1. Dynamic Causal Modelling for ERP/ERFs
Practical session
Stefan Kiebel and Rosalyn Moran

2. estimated by perturbing the system and measuring the response
DCM for Evoked Responses 3 4
STG
STG
functional connectivity vs. effective connectivity
causal architecture of interactions
estimated by perturbing the system and measuring the response 1 2 A1 A1
input
modulation of effective connectivity
The aim of DCM is to estimate and make inferences about the coupling among brain areas, and how that coupling is influences by changes in the experimental context.
differences in the evoked responses
changes in effective connectivity

3. Data acquisition and processing
mode 1
Data acquisition and processing
Oddball paradigm
standards
deviants
mode 2
pseudo-random auditory sequence
80% standard tones – 500 Hz
20% deviant tones – 550 Hz
time
preprocessing
mode 3
raw data
convert to matlab file
filter
epoch
down sample
artifact correction
average
data reduction to principal spatial modes
(explaining most of the variance)
128 EEG
scalp electrodes
ERPs / ERFs
time (ms)

4. The Mismatch Negativity (MMN) is the ERP component elicited by deviations within a structured auditory sequence peaking at about 100 – 200 ms after change onset. b 4
standards
deviants 3
MMN
HEOG
VEOG 2 a 1 V m -1 -2 -3 -4
-100
-50 50
100
150
200
250
300
350
400 ms c

5. Motivation for MMN model
plausible models…
Forward - F
Backward - B
Both - FB
Opitz et al., 2002 3 4
STG
STG
lA1
rA1
lSTG
rSTG 1 2 A1 A1
input
Doeller et al., 2003
modulation of effective connectivity

6. Intrinsic connections
Matlab
spm eeg
choose time
window
choose data
number of spatial
components
sources or nodes
in your graph
from
DCM.AF
DCM.AB
DCM.AL
specify extrinsic
connections
driving input to
DCM.C
modulations
Intrinsic connections
DCM.B
estimate the model
visualise
output

7. DCM specification – testing different models
Forward and
Forward - F
Backward - B
Backward - FB
STG
STG
STG
STG
STG
STG
STG A1 A1 A1 A1 A1 A1
input
input
input
Forward
Forward
Forward
Backward
Backward
Backward
Lateral
Lateral
Lateral
modulation of effective connectivity

8. results Bayesian Model Comparison log-evidence group level subjects
Forward (F)
Backward (B)
Forward and Backward (FB)