To assess inter-regional interactions throughout the brain, we employed a beta time series approach as described by Rissman and colleagues17. Briefly, each voxel's BOLD response in the task was modeled in a general linear model (GLM) as an individual regressor specifying the onset of each trial convolved with the canonical hemodynamic response function (HRF), resulting in 128 covariates of interest. The parameter, or beta, estimates derived for each trial for each voxel were then sorted by condition (spatial, temporal, correct, or incorrect trials) into a beta series. The spatial and temporal conditions consisted of both correct and incorrect retrieval questions to determine networks involved in the general process of spatiotemporal retrieval. The beta series of voxels belonging to an ROI were subsequently averaged culminating in twenty-six average beta series per condition. Finally, the Pearson product-moment correlation coefficient between all ROI's beta series was computed, creating a correlation matrix of all pairwise combinations (26 × 26) describing the strength of the functional relationship between two regions.
