Figure 5.

Statistics of individual nodes. (A) (Top) Scatter plot of rates vs. CVs across neurons in a single network with low average CV. Colors indicate the value of the in-degree of neurons. Histogram: distribution of rates in the network. (Middle) Corresponding scatter plot of CVs vs. excitation/inhibition ratio g_loc of the single neurons as well as distribution of g_loc. (Bottom) Scattered rates vs. g_loc. (B) Same as (A), but for network with high average CV. (C,D) Relation between mean firing rate and CV of a single LIF neuron, depending on mean μ and standard deviation σ of voltage fluctuations. The parameters μ, σ denote the mean and standard deviation of the free membrane potential due to input currents. (C) Contours for constant μ and increasing σ (higher rates for higher σ). (D) Same data, but contours drawn for constant σ and increasing μ (higher rates for higher μ). The shape of the CV-rate dependency in neurons within networks [top panels in (A,B)] suggests that high firing rates result from an increase in input mean rather than variance.