Figure 4. Scotopic 15 Hz flicker electroretinogram characteristics in the proband (A), case II 1 (B), and a control subject (C) are presented. Various intensities between −3.4 log scot td-sec and +0.35 log scot td-sec were performed. Dashed lines show the response filtered using a simple Fourier domain, bandpass filter (13–18 Hz). In the control panel (C), the rod system activity observed between −3.40 log scot td-sec and −2.0 log scot td-sec intensities originates from the slow rod pathway. At an intensity of −1.52 log scot td-sec, there is no discernable rod activity denoting neutralization of activity between the slow and fast rod pathways (C). At intensities of −1.30 log scot td-sec, the rod system activity reappears (which is out of phase to the response seen at −2.0 log scot td-sec and originates in the fast rod pathways), which progressively increases in amplitude and shows progressive advancement in phase (C). In case IV 1 and case II 1, the rod activity is discernable only at intensities higher than +0.19 log scot td-sec and −0.62 log scot td-sec, respectively (figures A and B, respectively). This suggests that only residual fast rod pathway activity is seen in CACNA1F-related disease.