Prolonged monocular deprivation (7 days) of the dominant, contralateral eye, initiated in adulthood (P90) and chronic monocular deprivation (from P21 – P100) induced a significant decrease in the VEP contralateral bias in adult wild type, but not NARP −/− mice. Diazepam (DZ, during the last 5 days of chronic MD) enabled ocular dominance plasticity in chronically- deprived NARP −/− mice, but does not change the ocular dominance shift in wild type mice. One way ANOVA (F7,32=18.706, p<0.001); *p<0.05 Bonferroni's post hoc versus WT no MD. Normal VEP contralateral bias is depicted by grey horizontal bar. Inset: representative VEP waveforms. C=contralateral eye, I=ipsilateral eye. Scale bars: 50 ms, 50 µV.