Electroretinography in NCBE-deficient mice indicates ON bipolar cell dysfunction.

<p><i>A, D,</i> Representative single flash ERG recordings from NCBE WT (black) and KO (red) mice (age 12 months) for increasing intensities under dark-adapted (<b><i>A</i></b>, scotopic) and light-adapted (<b><i>D</i></b>, photopic) conditions. <b><i>B, C, E, F,</i></b> Box-and-whisker plots of single flash ERG b-wave amplitudes (<b><i>B, E</i></b>) and latencies (<b><i>C, F</i></b>), plotted against flash intensity. Scotopic b-wave but not a-wave amplitudes in NCBE KO mice were reduced (<b><i>A,</i></b><i> </i><b><i>B</i></b>), and b-wave latencies (<b><i>C</i></b>) were increased compared to NCBE WT mice. <i>Inset</i> in <b><i>C</i></b>: Overlay of scotopic single flash ERG response traces of NCBE WT (black) and NCBE KO (red) mice at −2.0 log cd*s/m² intensity (arrow head). Scale bar: horizontal 50 ms, vertical 100 µV. Under photopic conditions, b-wave amplitudes (<b><i>D, E</i></b>) and b-wave latencies (<b><i>F</i></b>) of NCBE KO mice were similarly affected. <b><i>G,</i></b><i> </i><b><i>I,</i></b> Representative ERG recordings of a flicker frequency series (flash intensity <b><i>G</i></b>: −2 log cd*s/m²; <b><i>I</i></b>: 0.5 log cd*s/m²) under scotopic conditions. Flicker amplitudes (<b><i>H, J</i></b>) of NCBE KO mice decreased at much lower flash frequencies than that of WT controls. Vertical lines an <b><i>A</i></b>, <b><i>D</i></b>, <b><i>G</i></b>, <b><i>I</i></b> represent stimulus onset. In all quantitative plots (<b><i>B, C, E, F, H, J</i></b>), boxes indicate the 25% and 75% quantile range, whiskers indicate the 5% and 95% quantiles, and solid lines connect the medians of the data. NCBE WT (n = 2), NCBE KO (n = 3).