Schematic description of performance-based connectivity analysis. The first stage determines if there is a linear combination of regional blood flow values that predicts a specific behavior measured during functional brain imaging (top row). Regions that meet this requirement are called primary predictors (red and green regions, bottom right). In this example, the primary predictors are the right caudate nucleus (red), which was shown to have a negative relationship with speech rate, and the left inferior frontal region (green), which was shown to have a positive relationship with speech rate (Sidtis et al., 2003, 2006, 2010). The second stage examines the relationships between the predictor regions and the remaining regions using partial correlations, controlling for the influence of the region contralateral to the predictor (Sidtis, 2012a).