psychophysiological interaction
An fMRI analysis method examining how functional connectivity between brain regions varies with experimental conditions.
Full Definition
Psychophysiological interaction (PPI) analysis is a specialized fMRI technique that investigates context-dependent changes in functional connectivity between brain regions. Unlike standard functional connectivity analyses that examine correlations across entire time series, PPI specifically tests whether the strength of connectivity between a seed region and other brain areas differs significantly between experimental conditions or psychological states. The method combines physiological variables (neural signals) with psychological variables (task conditions) to identify their interaction effects. PPI analysis is particularly valuable for understanding how brain networks reorganize during different cognitive demands and has become a standard approach for studying dynamic functional connectivity in neuroinformatics research.
Usage
Usage note: Often abbreviated as PPI; ensure interaction term is properly specified in methods.
In Context
- "Psychophysiological interaction analysis revealed enhanced connectivity between amygdala and prefrontal cortex during emotional processing." — Results section
- "The PPI model included task regressors and their interaction with the seed time series." — Statistical analysis methods