Year: 2026
Type: preprint
Abstract: Understanding the neural basis of human cognition requires measuring not only localized brain activity but also how functional interactions between brain regions change in response to different cognitive demands. Event-related fMRI is an efficient design for linking trial-wise behavioral and computational variables to brain activity, but comparable methods for examining their effects on functional connectivity remain limited. Here, we develop beta-PPI (beta-series psychophysiological interaction), a method that leverages single-trial response estimates from even-related fMRI to quantify how trial-wise variables modulate functional connectivity. This task-based functional connectivity method provides a flexible approach for studying functional connectivity for event-related fMRI designs. We evaluated beta-PPI using comprehensive simulations across several experimental conditions and signal qualities. Beta-PPI can sensitively detect ground-truth effects and exhibited good parameter recovery. Compared with generalized psychophysiological interaction, beta-PPI achieved comparable performance across most conditions while demonstrating improved statistical power under lower signal-to-noise conditions. We further validated beta-PPI using empirical event-related fMRI data. Distinct trial-wise cognitive variables selectively modulated functional connectivity during their corresponding trial epochs, demonstrating the temporal specificity and flexibility of the approach. By testing how trial-wise variables modulate functional connectivity, beta-PPI extends task-based connectivity analysis to model-based fMRI and provides a common single-trial framework that could facilitate the integration of connectivity, activation, and representational analyses in event-related Fmri.
Institution: University of Iowa
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7169870418