Figure 1

Synaptic scaling after inactivation alone is reflected in the amplitude of miniature, but not evoked, currents. A, Following inactivation alone, mEPSC amplitude is enhanced in chronically TTX-treated culture; (p < 0.0001, KS test; n{CTL,TTX} = 1595,1390 events). Control cultures are shown in black, and TTX-treated cultures are shown in red. Inset: example mEPSCs. B, The frequency of mEPSCs is differently distributed in TTX-treated culture (one point per cell; KS Test: p < 0.005; Bartlett’s test for equal variances: p < 10^-10; n{CTL,TTX} = 68,60 cells); Inset: Mean +/- SEM (dark bars); median and interquartile range (light bars). C, In paired recordings between random neurons, monosynaptic connections probed by the first stimulus following TTX washout showed evoked EPSCs (eEPSCs) of similar amplitude in control and TTX-treated networks. Inset: mean amplitude (p > 0.35, Wilcoxon Rank Test; p > 0.6, KS Test); circles indicate experiments conducted in 500 nM CNQX and renormalized to full amplitude; triangles indicate no drug. D, The fraction of postsynaptic neurons showing an eEPSC in response to the first presynaptic stimulus was similar in control and TTX-treated cultures (p > 0.3).