A Multi-Subject, Dynamic Bayesian Networks (DBNS) Framework for Brain Effective Connectivity

As dynamic connectivity is shown essential for normal brain function and is disrupted in disease, it is critical to develop models for inferring brain effective connectivity from non-invasive (e.g., fMRI) data. Increasingly, (dynamic) Bayesian network (BNs) have been suggested for this purpose due to their flexibility and suitability. However, ultimately extrapolating BN results from one subject to an entire population first requires methods meaningfully addressing inter-subject, within-group variability. Here we explore two group analysis approaches in fMRI using DBNs: one is to construct a group network based on a common structure assumption across individuals, and the other is to identify significant structure features by examining DBNs individually-trained. By investigating real fMRI data from Parkinsons disease (PD) and normal subjects performing a motor task at three progressive levels of difficulty, we noted that both methods detected statistically significant, biologically plausible connectivity between task-related region-of-interest (ROIs) that differed between the PD and normal subjects. However, the second approach was more sensitive, finding more features that were also consistent with prior neuroscience knowledge. Determining highly reproducible DBN nodes/edges across subjects seems promising for inferring altered functional connectivity within a group.