Supplementary Figure 1: Intrinsic properties of cortical neurons in culture vs density and age.
From: Synaptic scaling rule preserves excitatory–inhibitory balance and salient neuronal network dynamics
Intrinsic properties vs. neuronal density (a) or days in vitro (DIV, b). Data presented as mean ± STD (n = 491 neurons in 165 preparations). To quantify the relation between the measured parameters and density or DIV, Spearman Correlation and p-values (*: p < 0.01; **: p < 0.001) were calculated (green). To determine whether there were significant changes in the parameters with density or DIV, we compared the values at the lowest and highest densities and DIV (50 points from each end of the plots) and calculated Mann-Whitney U-test p-values (red). Note that for density there were no statistically significant differences in the measured properties (a). Several parameters (input resistance, rheobase, F0.5) changed with DIV (b) but all had reached steady-state by 2 weeks, when the experiments were performed.
Abbreviations: Vm, membrane potential; Rm, input resistance; τ, membrane time constant; HW, half width of action potential; AHP, afterhyperpolarization; FI: slope of the firing vs current plot; F0.5, firing rate evoked when 0.5 nA current step was injected. Rheobase is minimum current to evoke a spike. Spike threshold is measured from resting membrane potential.
