Membrane potential at different contrasts. (A) Left: Tuning of the membrane potential of the same neuron as in Figure 15 for different contrasts. Center: Average tuning curve of 24 (12 excitatory, 12 inhibitory) randomly sampled neurons, ranging over all POs. The tuning curves are aligned at a PO of 90°. Error bars indicate mean±std over sampled neurons. To improve the display, they are plotted only for every third data point. The mean membrane potential (over all neurons and all orientations) is indicated by solid, horizontal lines in each case. The shading represents the standard deviation (over neurons) of the mean (over orientations) of the average membrane potential (v
). Right: Same as the panel in the center, for the free membrane potential, Vfm =V + τ rV reset. (B) The same mean±std (over sampled neurons) of tuning curves for the distance to threshold of free membrane potentials (Vfm − Vth), for different regimes of recurrence. For the lowest contrast, most of the error bars are smaller than the size of markers and hence not visible. The mean membrane potential and its standard deviation over the (sampled) population is shown, as before, by horizontal lines and shadings, respectively.