Figure 3

Functional connectivity analyses for (A) Seed-based functional connectivity analysis between the right ipsilateral primary motor cortex (seed) and the rest of the brain in the 50% MVC condition, data is a Z-statistic threshold map in standard space. Z-threshold = 3.1. Figure is in radiological view (left on right, right on left). (B) Change in interhemispheric functional connectivity between contralateral and ipsilateral primary motor cortices (M1–M1; red data points), and the contralateral and ipsilateral supplementary motor areas (SMA–SMA; orange data points) for 5% MVC (circles) and 50% MVC (triangles). Back horizonal bar represents the mean change. Grey shaded area represents the standard deviation. p = 0.007: significant condition × ROI × time interaction, p = 0.004: significant ROI × time interaction for 50% MVC condition, p = 0.045: significant paired-sample t-test for SMA–SMA connectivity, and (C) Scatter plot correlation between X-axis: The change in interhemispheric functional connectivity z-scores between the contralateral left and ipsilateral right supplementary motor areas (SMA-SMA) and Y-axis: beta values representing the decline in motor performance over time (negative slope = performance decline over time) (r²_adjusted = 0.208, p = 0.050, β = − 0.157). Figure 3A was made in MRIcoGL⁶¹.