Continuum spans transition from weakly to strongly correlated cortical state.

<p><b>(a,b)</b> Zero-lag Pearson correlation coefficients were computed for all electrode pairs (n = 496) during ongoing activity. Shown are example distributions of all pairwise correlations for unaltered inhibition (black), increased inhibition (blue), and decreased inhibition (red). Broader distributions for unaltered inhibition indicate that correlations are more diverse than for either increased or decreased inhibition. Data in (a) are from one rat; data in (b) is from another rat. <b>(c)</b> Mean pairwise correlations undergo a sigmoidal increase as κ increases, with κ = 1 dividing weakly correlated cortical states from strongly correlated states. To illustrate this trend, we computed the mean pairwise correlation for each experiment and present the mean (line) ± standard error (shaded areas) across all experiments with similar κ. <b>(d)</b> The model undergoes a similar transition from weak to strong population correlations as inhibition is tuned from strong to weak (blue to red, color map the same as <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004576#pcbi.1004576.g002" target="_blank">Fig 2H</a>). <b>(e)</b> Model results match experiments more closely when model state is parameterized by κ.