Evaluation of Visual Acuity in MOG-Induced EAE

Mouse VA was assessed using the Virtual Optometry System (OptoMotry, Cerebral Mechanics, Inc., Canada). Briefly, the virtual rotating columns were projected on the LCD monitors with different spatial frequencies in cycles/degree (c/d). The mouse head movement in response to the virtual column rotations was noted. The spatial frequency was starting from 0.1 c/d with step size of 0.05 c/d until the mouse stopped responding. The VA was defined as the highest spatial frequency to which the mouse responded to the virtual rotating columns. Each mouse was confirmed to have normal VA before immunization. After immunization, daily VA was assessed until VA ≤ 0.25 c/d, our definition for the onset of ON in MOG_35–55 EAE mice (Chiang et al., 2014 (link); Lin et al., 2014a (link),b (link)). The first day of VA ≤ 0.25 c/d both Dex- and PBS-treated group was 13.4 ± 3.7 days post immunization. Upon Dex treatment commencement, VA was performed twice a week and 1 day before MRI scans.