Fig. 4

Functional brain images at various time points after SNI. In each sub-figure, statistical t-maps are shown in 8 consecutive coronal slices of the rat brain, 1 mm each, from the most caudal level (5 mm caudal to the bregma, upper-left corner) to the most rostral (2 mm rostral to the bregma, lower-right). (a) Brain responses to SNI surgery during fMRI scanning. Positive BOLD responses are shown in the S1HL area (blue arrows), CC (purple arrows), and RAIC (yellow arrows) (n = 7, four males and three females). (b) MEMRI voxel-wise comparison of brain activity between the SNI (n = 10), sham (n = 10), and naïve (n = 10) rats on Day 1 after SNI surgery. The SNI group exhibited reduced activity in the S1 contralateral to the injured hind limb (blue arrows) and increased activity in the ipsilateral AIC (green arrows). (c) MEMRI voxel-wise comparison of brain activity between the SNI (n = 10), sham (n = 8), and naïve (n = 10) rats on Day 8 after SNI surgery. The SNI group exhibited increased activity in the RAIC and AIC (yellow and green arrows, respectively). The SNI and sham groups respectively shown in (b) and (c) were independent. Note Robust RAIC activation induced immediately after SNI (yellow arrow in a). The enhanced RAIC activity was maintained over 8 days (green arrows in c)