Figure 5. Mice expressing E50K human mutant optineurin demonstrate functional visual impairment.

(A) Contrast sensitivity testing by VEP. (A1) Representative VEP waveforms recorded. (A2 & A3) Visual responsiveness to patterned stimuli of decreasing contrast was significantly diminished in BAC hOPTN^E50K mice compared to wildtype littermates between the range of 100 to 12 percent contrast (p = 0.008). Note that the x-axis is plotted logarithmically. (A4) Logarithmic regression shows normal contrast sensitivity threshold. (B) Visual acuity testing by VEP as spatial frequency in cycles per degree (cpd). (B1) Representative VEP waveforms. (B2 & B3) VEP responses were reduced at 0.05 cpd in BAC hOPTN^E50K mice (p < 0.001), but were comparable at other spatial frequencies to wildtype littermates. (B4) Linear regression showed similar visual acuity threshold for both genotypes. (C) VEP waveform latency revealed no delay in nerve conduction in 18-month old BAC hOPTN^E50K mice. (C1) The averaged VEP waveform shows the initiation of the VEP which is when the visual signal was first detected in the primary visual cortex following visual stimulation. (C2-C4) There was no temporal delay in the initiation of the visual cortical response (Time to VEP), the negative peak (Time to N1) or positive peak (Time to P1) following visual stimulation. n = 11 WT, n = 8 for E50K, data represent means ± SEM. **p < 0.01, ***p < 0.001.