Figure 6. Difference in spatial frequency–dependent magnetic resonance imaging cortical activation. The percent change in the magnetic resonance (MR) signal is plotted as a function of the spatial frequency of the checkerboard pattern. Compared to the normal vision control group, the mean percentage change decreased significantly in the amblyopia groups across a range of spatial frequencies. There was no significant difference between the strabismic group and the anisometropic group at 60 s and 30 s checkerboard patterns, while the anisometropia reduced the cortical response to the 15 s checkerboard pattern (high-spatial-frequency) stimulus in the bilateral Brodmann areas (BA) 17. anisometropic amblyopia: 20 subjects; strabismic amblyopia: 17 subjects; normal vision volunteers: 16 subjects. *means p<0.05, **means p<0.01.