Featured Projects
Check out a few of our featured projects. For more information on these projects, or to see other projects that are currently going on in the lab, check out our full list of projects here. For big picture overviews of what SFIM has done, please check out our past BSC reviews (2003, 2007, 2012, 2016, 2020).
Layer-Specific fMRI
We are working to improve the spatial resolution and specificity of fMRI so that it is possible to distinguish neural activity changes across cortical layers.
Selected Publications
BOLD Connectivity Dynamics
A common assumption in most resting state fMRI (rsfMRI) studies is temporal stationarity. However, recent work has shown that rsfMRI connectivity patterns change considerably across short periods of time, even within the length of a typical rest scan. Little is known about this phenomenon (see Hutchinson et al. 2013 for an in-depth review of this topic). For example, we don't know yet what is the most appropriate temporal scale to investigate this phenomenon. We also don't know if all connections have similar or different levels of variability. Moreover, the potential relationship between fMRI connectivity changes and ongoing cognition is not yet fully understood. Several projects at the SFIM focus on characterizing and understanding BOLD connectivity dynamics both during undirected rest and task.
Tracking Ongoing Cognition in Individuals using Brief, Whole-Brain Functional Connectivity Patterns
Functional connectivity (FC) patterns in functional MRI exhibit dynamic behavior on the scale of seconds, with rich spatiotemporal structure and limited sets of whole-brain, quasi-stable FC configurations (FC states) recurring across time and subjects. Based on previous evidence linking various aspects of cognition to group-level, minute-to-minute FC changes in localized connections, we hypothesized that whole-brain FC states may reflect the global, orchestrated dynamics of cognitive processing on the scale of seconds. To test this hypothesis, subjects were continuously scanned as they engaged in and transitioned between mental states dictated by tasks. FC states computed within windows as short as 22.5 s permitted robust tracking of cognition in single subjects with near perfect accuracy. Accuracy dropped markedly for subjects with the lowest task performance. Spatially restricting FC information decreased accuracy at short time scales, emphasizing the distributed nature of whole-brain FC dynamics, beyond univariate magnitude changes, as valuable markers of cognition
Edge time series exploration: probing fine-scale connectivity patterns and dynamics
What's in a functional correlation? Using a simple technique to temporally unwrap Pearson correlation, we can observe the instantaneous similarities between two areas of the brain. These instantaneous similarities, which form so-called 'edge time series', have the potential to reveal different information about the brain's connectivity dynamics. For this project, we report on varying elements of edge time series information, such as describing the conditions that lead to high amplitude (i.e., spiking) events and measures capturing connectivity variability.
Selected Publications