Prospective slice-by-slice motion correction reduces false positive activations in fMRI with task-correlated motion

Objective: We aimed to test the hypothesis that slice-by-slice prospective motion correction at 7 T using an optical tracking system reduces the rate of false positive activations in an fMRI group study with a paradigm that involves task-correlated motion. Materials and methods: Brain activation during right leg movement was measured using a block design on 15 volunteers, with and without prospective motion correction. Clearly erroneous activations were compared between both cases, at the individual level. Additionally, conventional group analysis was performed. Results: The number of falsely activated voxels with T-values higher than 5 was reduced by 48% using prospective motion correction alone, without additional retrospective realignment. In the group analysis, the statistical power was increased — the peak T-value was 26% greater, and the number of voxels in the cluster representing the right leg was increased by a factor of 8.3. Conclusion: Slice-by-slice prospective motion correction in fMRI studies with task-correlated motion can substantially reduce false positive activations and increase statistical power