Correlation among fMRI Contrast of ANT
The unsatisfactory
reliability estimates might be due to the collinearity of conditions for
calculating attention network contrast. We calculated the correlation
among the eight contrasts using the region-based activations to verify
the prediction. As demonstrated by Figure 6 , there was severe
collinearity between the congruent and incongruent condition (r =
0.86), alerting contrast and center cue condition (r = 0.66), and
orienting contrast and spatial cue condition (r = 0.50). The
executive contrast shared few variances with the congruent (r =
-0.12) and incongruent conditions (r = 0.40), which might
question the usage of executive contrast to measure the executive
process as the interested part had been canceled out because of
subtraction.