Functional Diffusion Tensor Imaging: Measuring Task-Related Fractional Anisotropy Changes in the Human Brain along White Matter Tracts (original) (raw)
Figure 4
Time course experiment.
The time courses of the diffusion weighted MRI signal for the visual and the tactile task measured perpendicular to the tract's main direction using a single stimulus. An increase in glial cell volume is expected to lead to an increase of the measured signal. The tactile and the visual stimulus period (red horizontal line) started at t = 12 s and ended at t = 72 s. a) The results represent the averages of 15 measurements (3 subjects; 5 measurements per subject) smoothed using a Gaussian kernel with sigma = 14 s. For the tactile stimulus (green) the maximum signal was found at t = 78 s. For the visual stimulus (blue) the maximum signal was found at t = 98 s. b) The averages of the signals of the background voxels that were used to correct for global signal variations (dashed blue line for the visual task and green dashed line for the tactile task). Note that these signals were independently scaled for visualization.