Figure 1.
Percentage of freezing behavior during pre-shock period (free exploration), FC period (three paired CS with US), and cue/contextual test performed one month post-FC. One-way ANOVA with Dunnett’s multiple comparison test was employed (***p<0.001). Error bars represent the standard error of the mean (n = 8).
Figure 2.
Statistical maps from voxel-wise planned comparisons between time points for FA.
Upper row: statistical maps (colored regions) from planned comparisons are overlaid on a mean fractional anisotropy (FA) map (shown in corresponding axial, coronal and sagital views respectively) averaged from all animals. In the clusters indicated by arrows, FA first increased then decreased in amygdala (Amg, p<0.005, 31 voxels, n = 18), first decreased then increased in hippocampus (HP, p<0.005, 33 voxels, n = 9), and kept increasing in cingulum (CG, p<0.005, 49 voxels, n = 18) 1-hr, 1-day post-FC respectively. Colors are coded according to the threshold they exceeded. Lower row: corresponding FA values were presented by normalization of pre-FC at all time points within the significant voxels. Error bars represent mean ± standard error of the mean (n = 18 for Amg and CG, n = 9 for HP).
Figure 3.
ROIs obtained from the significant clusters pointed in Figure 2. ROIs were overlaid on an FA map averaged from all animals. Cingulum and adjacent gray matter (red), amygdala (blue) and hippocampus (green) are shown from anterior to posterior (left to right, up to down).
Figure 4.
DTI quantification on the ROIs.
FA, MD (in µm2/ms), radial diffusivity (λ⊥ in µm2/ms) and axial diffusivity (λ// in µm2/ms) between time points were compared using repeated measures ANOVA with Tukey’s multiple comparison test (*p<0.05, **p<0.005, ***p<0.001). Error bars represent standard error of the mean (n = 18 for Amg and CG, n = 9 for HP).
Table 1.
Comparisons of DTI quantitation measurements between current study and previous studies.