input single-state dcm intrinsic (within- region) coupling extrinsic (between- region) coupling...

u

ijij uBA

input

Single-state DCM

1x

Intrinsic (within-region) coupling

Extrinsic (between-region) coupling

NNNN

N

x

x

x

AA

AA

A

CuxuBAx

1

1

111

)(

Multi-state DCM with excitatory and inhibitory connections

Ex1

IN

EN

I

E

AA

AAA

AA

AAA

u

x

x

x

x

x

ee

eee

ee

eee

A

CuxABx

IINN

IENN

EENN

EENNN

IIIE

NEIEE

1

1

00

0

00

0

)(

1

1111

11111

)exp( ijij uBA

Ix1

)exp( 1111IEIE uBA IEx ,

1

The basic approach

Variational free energy

),(

),,(

xgy

uxfx

u

Fmyp

Fyp

qFyp

m

qq

min)|(

min)|(

min)|(,

),()(

))(),((),|(

Np

gNyp

),(

))|(,()|(ln

ln)|,(ln

qq

q

Nq

ypqKLyp

qypF

Minimise free energy

Make inferences

Define likelihood model

Specify priors

Neural dynamics

Observer function

Extrinsicforward

connections

spiny stellate

cells

inhibitory interneurons

pyramidal cells

4 3

236

746

63

225

1205

52

650

214

014

41

278

038

87

2)(

2))()()((

2))()((

2))()((

iii

i

ee

LB

e

e

ee

LF

e

e

ee

LB

e

e

xxxS

Hx

xx

xxxSxSAA

Hx

xx

xxx

xxCuxSIAA

Hx

xx

xxxSIAA

Hx

xx

1 2)( 0xSAF

)( 0xSAL

)( 0xSABExtrinsic backward connections

Intrinsic connections

neuronal (source) model

Extrinsic lateral connections

State equations

,,uxfx

Output equation

0, Lxxg y

A1 A1

STG

ForwardBackward

Lateral

input

Forward and Backward - FB

STG

IFG

2.4

1 (

10

0%

) 4.5

0 (1

00

%) 5

.40

(1

00

%) 1

.74

(96

%)

1.4

1 (

99

%) 0

.93

(55

%)

mode 1

mode 2

mode 3

A1A1

STGSTG

IFG

Changes in extrinsic connections with ‘oddballs’

FFB

lo

g ev

iden

ce Bayesian Model Comparison

subjects

Forward (F)

Backward (B)

Forward and Backward (FB)

Two subgroups