Functional assessment of <i>Ndph</i>^<i>y/-</i> and corresponding control mice based on ERG at 2 months.

<p>Quantitative evaluation (box-and-whisker plot) of the scotopic (A, left) and photopic (B) b-wave amplitude data for <i>Ndph</i>^<i>y/-</i> mice (grey) and controls (black). Additional quantification of scotopic a-wave amplitude (A, right). Boxes indicate 25% and 75% quartiles, whiskers 5% and 95% quantiles and the asterisks the median of the data. (C) Selected single flash ERG traces for the scotopic -2.0 log (cd*s/m2) stimulus intensity, representing pure rod system response (top) and the scotopic 1.0 log (cd*s/m2) stimulus intensity (center; mixed rod-cone system response) and photopic 1.0 log (cd*s/m2) stimulus intensity (bottom; cone system response). The scotopic and photopic b-wave amplitudes were significantly reduced in <i>Ndph</i>^<i>y/-</i> mice when compared to control animals. Representative single ERG traces showed a large reduction of b-wave amplitude leading to a “negative ERG” in scotopic conditions in <i>Ndph</i>^<i>y/-</i> mice and making a lack of oxygen very probable to be the source of the functional defects. In addition, a complete loss of oscillatory potentials in both scotopic and photopic conditions was observed.