Figure 3
(a) Linear regression between absolute monthly change in discrimination index and retinal layer thickness measured by OCT in 4-month-old C57BL/6J mice. Discrimination indices were quantified by a NORT at 4 months of age, 6 months of age and 9 months of age. The absolute monthly change in discrimination indices was calculated by the difference in discrimination indices divided by the time elapsed between the measurements in 4, 6, and 9 months. Absolute monthly changes in retinal layer thickness were calculated similarly. Relationships were considered significant if the gradient of regression lines were significantly non-zero. There is a significant positive linear relationship between the absolute monthly change in INL thickness and the absolute monthly change in discrimination index (y = 3.046x − 0.5284, r2 = 0.2970, p = 0.0059). (b) Violin plot of the absolute monthly change in retinal layer thickness in C57BL/6J mice with and without NCD. Based on the DSM-V, the threshold of NCD was set as an absolute monthly change in discrimination index less than one standard deviation below the mean, which was − 0.2222 (µ = − 0.0579, σ = 0.1643). Mice below this threshold were considered to have NCD, and mice above this threshold were considered to have no NCD. Data were first analyzed with an F test for equal variances. Normality of residuals was determined through Anderson–Darling, D’Agostino-Pearson omnibus, Shapiro–Wilk, and Kolmogorov–Smirnov tests. INL data passed all normality and equal variance tests and were assessed with two-tailed unpaired t-tests. Absolute monthly change in INL thickness was significantly increased in mice without NCD compared to mice with NCD (p = 0.0083). INL inner nuclear layer, ONL outer nuclear layer. ** p < 0.01.
