Fig. 5

Comparison of mean HGB activity during the operand and operator periods. Each subplot represents one ROI of the arithmetic network indicated by the title (same conventions as in Fig. 1). For all channels assigned to each ROI, we computed the mean HGB responses across the operand (N1–N3) and operator (O1, O2) periods. We compared the relative changes (increases or decreases) of the channels’ mean HGB activities using the paired, two-tailed sign test. In each ROI, we tested: N1 vs. N2; N1 vs. N3; N2 vs. N3; O1 vs. O2. A star indicates significance of difference (P < 0.05, FDR-corrected for multiple testing).