Inferring consistent functional interaction patterns from natural stimulus FMRI data

There has been increasing interest in how the human brain responds to natural stimulus such as video watching in the neuroimaging field. Along this direction, this paper presents our effort in inferring consistent and reproducible functional interaction patterns under natural stimulus of video watching among known functional brain regions identified by task-based fMRI. Then, we applied and compared four statistical approaches, including Bayesian network modeling with searching algorithms: greedy equivalence search (GES), Peter and Clark (PC) analysis, independent multiple greedy equivalence search (IMaGES), and the commonly used Granger causality analysis (GCA), to infer consistent and reproducible functional interaction patterns among these brain regions. It is interesting that a number of reliable and consistent functional interaction patterns were identified by the GES, PC and IMaGES algorithms in different participating subjects when they watched multiple video shots of the same semantic category. These interaction patterns are meaningful given current neuroscience knowledge and are reasonably reproducible across different brains and video shots. In particular, these consistent functional interaction patterns are supported by structural connections derived from diffusion tensor imaging (DTI) data, suggesting the structural underpinnings of consistent functional interactions. Our work demonstrates that specific consistent patterns of functional interactions among relevant brain regions might reflect the brain's fundamental mechanisms of online processing and comprehension of video messages.

Visualization of the inferred consistent interaction patterns extracted via GES algorithm from natural stimulus fMRI data in the functional brain networks include auditory/language, motor, working memory and visual systems when subjects watched video clips. (a), (b) and (c) show the consistent connectivity patterns for video categories of advertisement, sports and weather report, respectively. The nodes of the functional networks are represented as green spheres. The blue lines without arrows and with red arrows represent non-directional and directional connections, respectively. (d), (e) and (f) show the significance of consistency of the interaction connections demonstrated in (a), (b) and (c), respectively. The color bar is on the right side.378Highlights► Performed natural stimulus fMRI when subjects watched videos. ► Consistent interaction patterns can be inferred from relevant brain networks. ► GES, PC and IMaGES algorithms outperform GCA algorithm. ► Consistent functional interaction patters are supported by DTI data. ► Inferred interaction patterns are meaningful given current neuroscience knowledge.