Fig 1.
Raw signal and power spectrum analysis.
(a) Sample raw rs-BOLD signal from grey matter of an mTBI patient(a) and a healthy control brain(b). These time courses were specifically from a 4x4x3mm voxel in the right hippocampus, located at 24.0[L], 5.0[P], 15.0[S] mm in the N27 atlas. (c,d) Power spectrum, from the same voxel from Fig 1a and Fig 1b respectively, showing power-law decay on a log-log scale. A frequency range of 0.08–0.16 Hz was fit because of the consistency in power law scaling behavior (between and within subjects) of this spectral region.
Fig 2.
(a) Kolmogorov – Smirnov normality test. h = 1 indicates rejection of the null hypothesis at a 5% significance level. (b) Kurtosis map. Voxels where k ≠ 3.0 ± 0.5 were removed from analysis. The map was centered at k = 3. (c) Skewness map. Skewness measures asymmetry of the distribution. Positive skew(sk) indicates more data points above the mean while negative skew indicates more data points below the mean. Voxels where sk ≠ 0.0 ± 0.5 were removed from the analysis and the sk map was normalized.
Fig 3.
Montage showing 9 axial slices (taken every 5mm) through the TT_Daemon human brain atlas [22] with a selection of the 240 colour-coded brain structures identified.
Fig 4.
FD map over a gray matter mask for an mTBI patient(a) and a healthy control(b). FD values closer to 2 show increased signal complexity while FD values closer to 1 show decreased signal complexity in that region.
Fig 5.
Z-score map over grey matter mask was used to calculate the regions that significantly deviated (p = 0.01) from the mean FD. This particular patient showed significant FD decreased in the right hippocampus (red) and the right amygdala (green).
Fig 6.
Bar graph showing ROI frequency in mTBI. Regions where FD decreases significantly. i.e. 9 out of 15 patients showed decreased FD in the right amygdala while 5 out of 15 showed decreased FD in the right hippocampus.
Table 1.
Mean Z-score, standard deviation and p-values for ROI FD values that deviated greatest from healthy controls.
Table 2.
Pearson correlation coefficients and p-values of PCSS compared against regional rs-BOLD Z-score.
Table 3.
Qualitative criteria used to determine strength of the correlation between FD and PCSS.