**Figure 3. **Circadian rhythms in the
wild-type and *Gnat1*^{−/−} cone ERG. Wild-type mice
showed significant difference in b-wave amplitude (**A**) and
implicit time (**B**) over the course of light adaptation when
measured at CT6 (open circles) compared to CT18 (closed circles) F test
curve fit comparison p<0.0001 for each parameter. Similar effects of
circadian phase were observed on b-wave amplitude (**C**; F test
p<0.0001) and implicit time (**D**; F test p<0.0001) in *Gnat1*^{−/−}
mice. All data are shown as mean±SEM. Replicates for **A** and **B**
were: n=10 (CT6), n=8 (CT18), for **C** and **D**: n=8 (CT6),
n=6 (CT18). The estimated parameters for curve fit for the curves in **A**
were, CT6: Y_{0}=-5.061 a=149, k=0.124, CT18: Y_{0}=-2.029
a=127, k=0.1082. Estimated parameters for **B**, CT6: Y_{0}=83.39,
a=54.94, k=0.143, CT18: Y_{0}=96.08, a=59.07, k=0.176.
Estimated parameters for **C**, CT6: Y_{0}=88.72, a=194.4,
k=0.127, CT18: Y_{0}=46.62, a=159.3, k=0.0666. Estimated
parameters for **D**, CT6: Y_{0}=56.23, a=51.78, k=0.283,
CT18: Y_{0}=59.20, a=52.11, k=0.087.