BOLD changes in magnitude (M/M
0) and frequency shifts (Δω/ω
0) signals in the sagittal sinus. For two subject participating in Experiment 1: (A) M/M
0, and (B) Δω/ω
0 activity maps (red/green = positive/negative correlation with stimulus regressor, P < 0.05 Bonferroni corrected) overlaid on a magnitude EPI image; (C) magnitude EPI image; (D) high‐resolution gradient‐recalled echo image; (E) Δω/ω
0 and M/M
0 time‐courses in the sagittal sinus (the sign of Δω/ω
0 was inverted for display purposes only). The blue arrow indicates the location of the sagittal sinus. In subject 1 and 2, <ΔM
A‐B/M
0> was = 10.5 and 11.0%; <Δω
A‐B/ω
0> was = −2.4 and −2.6 ppb, yielding a <ΔY
A‐B> of 0.048 and 0.054, respectively.