Correlations in random, fixed in-degree networks.

<p>(<b>A</b>) A comparison of numerically obtained excitatory-inhibitory cross-correlations to the approximation given by Eq. (26). (<b>B</b>) Mean and standard deviation for the distribution of correlation functions for excitatory-inhibitory pairs of cells. (Solid line – mean cross-correlation, shaded area – one standard deviation from the mean, calculated using bootstrapping in a single network realization). (<b>C</b>) Mean and standard deviation for the distribution of cross-correlation functions conditioned on cell type <i>and</i> first order connectivity for a reciprocally coupled excitatory-inhibitory pair of cells. (Solid line – mean cross-correlation function, shaded area – one standard deviation from the mean found by bootstrapping). (<b>D</b>) Average reduction in error between cross-correlation functions and their respective first-order conditioned averages, relative to the error between the cross-correlations and their cell-type averages. Blue circles give results for a precisely tuned network, and red squares for a network with stronger, faster inhibition. Error bars indicate two standard errors above and below the mean. for panels A-C are as in the precisely tuned network of <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002408#pcbi-1002408-g006" target="_blank">Figure 6</a>, and the two networks of panel D are as in the networks of the same figure.