Figure 3. The averaged BOLD signal intensity changes in the non-headache controls (NHC) and the migraineurs. In the NHC, MRI signals were averaged over the left and right visual cortex (Fig. 2). MAS: migraine-affected side of the visual cortex of the migraineurs; OS: the opposite side of the visual cortex. 

Figure 5. Asymmetric visual activity in the migraineurs. The BOLD signal intensity changes in the migraine-affected side (MAS) of the visual cortex increased at SFs of 1.2, 3.0, and 6.0 cpd, compared with in the opposite side (OS) and in the non-headache controls (NHC). The increased neuronal activity was significant at 1.2 cpd SF (Wilcoxon signed-rank test, p<0.028, n=6).