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Blood oxygenation level dependent (BOLD) signal changes occurring during execution of a simple motor task were measured at field strengths of 1.5, 3 and 7 T using multi-slice, single-shot, gradient echo EPI at a resolution of 1×1×3 mm³, to quantify the benefits offered by ultra-high magnetic field for functional MRI. Using four different echo times at each field strength allowed quantification of the relaxation rate, R₂^⁎ and the change in relaxation rate on activation, ΔR₂^⁎. This work adds to previous studies of the field strength dependence of BOLD signal characteristics, through its: (i) focus on motor rather than visual cortex; (ii) use of single-shot, multi-slice, gradient echo EPI for data acquisition; (iii) co-registration of images acquired at different field strengths to allow assessment of the BOLD signal changes in the same region at each field strength. ΔR₂^⁎ was found to increase linearly with field strength (0.51±0.06 s …