Table 1. Clusters with significant changes in DTI indices of white matter microstructure after a day of waking (TP1 compared with TP2).
| DTI parameter | No. of voxels in cluster | Change after a day of waking | MNI (x, y, z) maxima | Anatomical region of the peak voxel a | Peak voxel P-value |
|---|---|---|---|---|---|
| FA | 21062 | ↑ | 39, −8, 27 | R SLF | 0.006 |
| 9273 | ↑ | −23, 31, 19 | L ATR, IFOF, UF | 0.024 | |
| 175 | ↑ | −8, −37, 56 | L Cingulum | 0.047 | |
| 64 | ↑ | −18, 11, −25 | L Orbitofrontal* | 0.046 | |
| 11 | ↑ | −15, −39, 63 | L CST | 0.049 | |
| 2 | ↑ | −18, −36, 62 | L CST | 0.049 | |
| RD | 30466 | ↓ | 34, −29, 37 | R SLF | <0.001 |
| MD | 9516 | ↓ | 28, −57, 19 | R IFOF, ILF, Fmaj | 0.005 |
| 62 | ↓ | −19, −37, 37 | L Cingulum | 0.048 | |
| 42 | ↓ | −19, −54, 43 | L Precuneus* | 0.048 | |
| 10 | ↓ | 45, −18, 45 | R Postcentral gyrus* | 0.048 | |
| 2 | ↓ | 33, −47, 29 | R SLF, ILF | 0.049 | |
| 1 | ↓ | 34, −48, 26 | R SLF, ILF | 0.049 |
DTI; diffusion tensor imaging. TP; time point. MNI; Montreal Neurological Institute. R; right. L; left. SLF; superior longitudinal fasciculus. ATR; anterior thalamic radiation. IFOF; inferior fronto-occipital fasciculus. UF; uncinate fasciculus. CST; cortico-spinal tract. Fmaj; forceps major. ILF; inferior longitudinal fasciculus.
aAnatomical region based on Johns Hopkins University (JHU) white matter tractography atlas and the ICBM-DTI-81 white matter labels atlas [36–38].
*Not within the white matter atlases; gross anatomical description.