The functional connectivity of cortical areas

1
The functional connectivityof cortical areas

• Or how to produce many numbers

2
Coordination of different modules
?
3
Structural equation modelling
Popular in behavioral sciences - e.g. whats
role of intelligence in performance? Identify
latent factors in data - structure in covariance
matrix - confirmatory vs exploratory Roots in
path analysis (Wright, 1921) General model
DATA MODEL ERROR - reduce
error http//www.gsu.edu/mkteer/semfaq.html
4
Graphical representation
5
Formal representation
Measurement weighted latent factors error
6
Aplication to fMRI data
Effective connectivity vs functional
connectivity Ec influence of one neuronal
system on another Fc temporal correlation of two
neurophysiological events Anatomy can inform
choice of factor loadings
7
How to estimate effects over time?
Simple regression model Y xB u Include
time Yt xtBt ut Estimate evolution B using
Kalman filter - predictor-corrector algorithm
8
The paradigm
I. Toni, J. Rowe, K.E. Stephan R.E.Passingham.
(2002). Changes of cortico-striatal effective
connectivity during visuomotor learning. Cerebral
Cortex 121040-1047
9
What are the modules?
10
The model
11
The result
12
What have we learned?
Your turn!
13
An application to fMRI