The average, SEM, and 95% confidence limits for the ERG regressions established from 5 trials in Figure 3. Amplitude (a) and timing (b) ERG gains whose 95% confidence limits encompass 1 indicate an ERG gain of unity. Those that are significantly greater than 1 indicate an amplification in gain (*) and significantly less than 1 a compression in gain (#). This indicates that the PIIIamp to PIIamp has a gain which encompasses unity whereas there is an amplification of gain between the PIIamp to pSTRamp and the PIIamp to nSTRamp. In terms of timing, there is an amplification of gain between the PIIIit to PIIit in contrast to a compression of gain between the PIIit to pSTRit and the PIIit to nSTRit.