Estimating trial-wise modulation of functional connectivity using event-related fMRI

Area of Science:

• Neuroscience
• Cognitive Science
• Functional Magnetic Resonance Imaging (fMRI)

Background:

• Understanding human cognition requires analyzing both brain activity and functional connectivity.
• Event-related fMRI is useful for linking behavior to brain activity, but methods for studying its impact on functional connectivity are limited.

Purpose of the Study:

• To introduce beta-PPI, a novel method for quantifying how trial-wise variables modulate functional connectivity in event-related fMRI.
• To provide a flexible task-based functional connectivity approach for event-related fMRI designs.

Main Methods:

• Developed beta-PPI, leveraging single-trial response estimates from event-related fMRI.
• Evaluated beta-PPI through comprehensive simulations and validated with empirical event-related fMRI data.
• Compared beta-PPI performance against generalized psychophysiological interaction.

Main Results:

• Beta-PPI effectively detects effects and shows good parameter recovery in simulations.
• Beta-PPI demonstrated improved statistical power in low signal-to-noise conditions compared to generalized psychophysiological interaction.
• Empirical data showed beta-PPI selectively modulated functional connectivity based on trial-wise cognitive variables, confirming temporal specificity.

Conclusions:

• Beta-PPI offers a flexible and powerful method for task-based functional connectivity analysis in event-related fMRI.
• This method extends task-based connectivity analysis to model-based fMRI.
• Beta-PPI provides a unified framework for integrating connectivity, activation, and representational analyses in fMRI research.