Suppression of correlations by purely inhibitory feedback in absence of external fluctuations.

<p>Activity in a network of binary inhibitory neurons with synaptic amplitudes . Each neuron receives randomly drawn inputs (fixed in-degree) with . <b>A</b> Population averaged activity. Numerical solution of mean field <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003428#pcbi.1003428.e150" target="_blank">equation (7)</a> (solid horizontal line). <b>B</b> Cross covariance between inhibitory neurons. Theoretical result (32) shown as dot. St. Andrew's Cross indicates the leading order term . <b>C</b> Correlation between the input currents to a pair of excitatory neurons. The black curve is the contribution due to pairwise correlations , the gray curve is the contribution of shared input . The dot symbols show the theoretical expectations (33) based on the leading order (crosses) and based on the full solution (32) (dot). Threshold of neurons .