FIG. 3.

The degree of contralesional blood oxygenation level–dependent (BOLD) activity increases at 4 weeks in response to unaffected limb stimulation. (A) Group mean, unaffected (left) forelimb–evoked activation data (one-tailed t-test, corrected for multiple comparisons, p < 0.001, z > 1.7) before and at 1, 2, 3, and 4 weeks after injury, superimposed on a rat brain template, and also shown as 3D surface projections. (B, C) Plots of contralesional cortex BOLD signal percent change during unaffected limb stimulation compared with at rest for all rats imaged (B) pre-injury and (C) at 4 weeks post-injury. (D) Quantified BOLD signal was significantly increased at 4 weeks post-injury compared with pre-injury, but not at earlier time-points (p < 0.001, linear mixed models analysis of variance). (E) Contrast plots of activated gray and white matter brain regions that were positively correlated to injury severity (tensor-based morphometry data) during unaffected forelimb stimulation at 4 weeks post-injury. *p < 0.05. Key: Hatched circle represents approximate position of primary injured region.