Summary
Introduction: This article is part of the Focus Theme of Methods of Information in Medicine on “Biosignal Interpretation: Advanced Methods for Neural Signals and Images”.
Background: Dynamic Causal Modelling (DCM) is a generic formalism to study effective brain connectivity
based on neuroimaging data, particularly functional Magnetic Resonance Imaging (fMRI).
Recently, there have been attempts at modifying this model to allow for stochastic
disturbances in the states of the model.
Objectives: This paper proposes the Multiple- Model Kalman Filtering (MMKF) technique as a stochastic
identification model discriminating among different hypothetical connectivity structures
in the DCM framework; moreover, the performance compared to a similar de terministic
identification model is assessed.
Methods: The integration of the stochastic DCM equations is first presented, and a MMKF algorithm
is then developed to perform model selection based on these equations. Monte Carlo
simulations are performed in order to investigate the ability of MMKF to distinguish
between different connectivity structures and to estimate hidden states under both
deterministic and stochastic DCM.
Results: The simulations show that the proposed MMKF algorithm was able to successfully select
the correct connectivity model structure from a set of pre-specified plausible alternatives.
Moreover, the stochastic approach by MMKF was more effective compared to its deterministic
counterpart, both in the selection of the correct connectivity structure and in the
estimation of the hidden states.
Conclusions: These results demonstrate the applicability of a MMKF approach to the study of effective
brain connectivity using DCM, particularly when a stochastic formulation is desirable.
Keywords
Stochastic - DCM - fMRI - Multiple-Model Kalman Filter