Figure 6.

Optogenetic manipulations do not change neuronal variability or correlations. A–C, Fano factor pooled across mice distributions are similar under light-on and light-off conditions. A, PV-ChR2; B, PV-Arch; C, CamK2a-ChR2. Black, Light-off trials; blue, green, red, light-on trials. D–F, Pairwise correlation distributions pooled across mice are similar under light-on and light-off conditions. D, PV-ChR2; E, PV-Arch; F, CamK2a-ChR2. Colors same as in A. G, Increasing Fano factor reduces Fisher information, shown here for a single neuron with Gaussian tuning curve (amplitude 8 spikes/s, center frequency 20 kHZ, tuning width 0.2 decades) with a constant baseline (2 spikes/s). H, Incorporating the measured Fano factors into our model of neuronal firing via a generalized Poisson model has a weak effect on the predicted threshold.