Table 1.
Simulation results from 500-msec-long records
| Condition | Rate (events/ msec) | Variance (pA2) | Skew (−10−34∗ A3) | 4th Moment (A4∗ −10−45) | 4th Cumulant (A4 ∗ −10−45) | AmpS (−pA) | Amp 4th (−pA) | RateS (events/msec) | Rate 4th (events/msec) |
|---|---|---|---|---|---|---|---|---|---|
| One-component mEPSC | 0.5 | 26 ± 2 | 3.0 ± 0.5 | 7 ± 2 | 5 ± 2 | 32.1 ± 3.4 | 32.0 ± 6.4 | 0.5 ± 0.1 | 0.5 ± 0.2 |
| One-component mEPSC | 1 | 50 ± 4 | 5.6 ± 0.9 | 16 ± 4 | 9 ± 3 | 30.8 ± 2.8 | 30.2 ± 5.3 | 1.0 ± 0.2 | 1.2 ± 0.6 |
| One-component mEPSC | 2 | 103 ± 8 | 11.7 ± 1.9 | 49 ± 11 | 17 ± 6 | 31.1 ± 3.0 | 27.9 ± 6.3 | 2.1 ± 0.3 | 3.6 ± 2.5 |
| One-component mEPSC | 5 | 255 ± 11 | 28.2 ± 4.1 | 240 ± 31 | 44 ± 24 | 30.6 ± 3.9 | 29.2 ± 12.7 | 5.4 ± 1.3 | 24 ± 60 |
| One-component mEPSC | 8 | 404 ± 21 | 44 ± 7 | 553 ± 68 | 63 ± 34 | 30.3 ± 4.0 | 26.7 ± 12.3 | 8.7 ± 2.3 | 38 ± 90 |
| One-component mEPSC | 12 | 606 ± 31 | 69 ± 15 | 1212 ± 182 | 108 ± 108 | 31.5 ± 5.9 | 27.2 ± 23.1 | 12.7 ± 4.2 | |
| One-component mEPSC | 24 | 1227 ± 65 | 150 ± 36 | 4784 ± 658 | 258 ± 269 | 33.6 ± 7.0 | 29.1 ± 26.6 | 23.2 ± 9.2 | |
| Sinusoidal modulation | 2 | 101 ± 6 | 11.1 ± 1.7 | 50 ± 9 | 19 ± 6 | 30.5 ± 3.4 | 32.9 ± 6.7 | 2.1 ± 0.4 | 2.0 ± 1.2 |
| Wider bandpass | 2 | 772 ± 67 | 172 ± 46 | 2388 ± 674 | 588 ± 420 | 31.1 ± 6.0 | 28.0 ± 13 | 2.2 ± 0.7 | 43 ± 240 |
| Two-component mEPSC | 2 | 97 ± 5 | 10.31 ± 0.4 | 44 ± 7 | 15 ± 5 | 30.9 ± 2.9 | 29.2 ± 7.1 | 2.1 ± 0.3 | 3.2 ± 2.2 |
| Include residual current | 0.5 | 25 ± 2 | 2.8 ± 0.5 | 6 ± 2 | 4 ± 1 | 30.6 ± 3.2 | 29.5 ± 5.8 | 0.5 ± 0.1 | 0.6 ± 0.3 |
| Include residual current | 2 | 103 ± 8 | 12.2 ± 2.3 | 53 ± 13 | 21 ± 9 | 32.6 ± 4.0 | 32.9 ± 8.1 | 1.9 ± 0.3 | 2.29 ± 1.1 |
| Include residual current | 8 | 407 ± 25 | 45.4 ± 8.8 | 573 ± 90 | 74 ± 45 | 30.6 ± 4.6 | 29.9 ± 14.1 | 8.8 ± 2.5 | |
| Include residual current | 24 | 1227 ± 69 | 140 ± 31 | 4674 ± 580 | 147 ± 216 | 31.4 ± 6.2 | 17.8 ± 27.8 | 26.9 ± 12.6 | |
| Plus channel noise | 0.5 | 33 ± 2 | 2.8 ± 0.5 | 8 ± 2 | 4 ± 1 | 30.9 ± 3.41-a | 28.8 ± 5.4 | 0.5 ± 0.1 | 0.79 ± 0.3 |
| Plus channel noise | 2 | 118 ± 9 | 12.1 ± 2.2 | 63 ± 13 | 21 ± 9 | 32.4 ± 4.1 | 32.3 ± 7.9 | 1.92 ± 0.4 | 2.39 ± 1.2 |
| Plus channel noise | 8 | 459 ± 25 | 44.3 ± 9.3 | 703 ± 97 | 69 ± 51 | 31.5 ± 5.3 | 29 ± 19 | 7.9 ± 2.4 | |
| Plus channel noise | 24 | 1421 ± 71 | 135 ± 33 | 6191 ± 665 | 120 ± 265 | 29.6 ± 6.7 | 13 ± 35 | 32 ± 19 |
Mean values and SDs for estimates of the cumulants, rates, and amplitudes are given at different release rates. Each simulation was run 50 times to determine means and SDs of the quantities tested. Rate estimates derived from skew and variance (abbreviated as AmpS and RateS) were calculated according to Equations 10-13. Similar estimates derived from fourth cumulant and skew (designated as AmpF and RateF) were calculated according to Equations 14 and 15. The first eight rows of the table show simulations for single-component mEPSCs at different rates with the amplitude distribution. H′s = 2.766, Z′s= 2490, H′4 = 1.941, and Z′4 = 7206 were used as calibration constants (see also Eqs. 12-15 and legend to Fig. 1B). For the subsequent rows (2 rows with different filtering and mEPSC waveforms and 8 rows including residual current and channel noise), values were recalculated according to the given waveform of the filtered mEPSC. The parameter i′ (Eq. 9) was 23.3 fA for the simulations at 0.5, 2, and 8 events/msec when channel noise was added and 14.3 fA for the simulation at 24 events/msec. These values were obtained from linear fits of variance against mean AMPA-induced current from exactly those traces used in the simulation. i′ = 0 was used for all other traces.
Extra variance of 5.6 pA2 was allowed in this calculation for amplifier and recording noise, which dominated in this case and was not accurately represented in the fits of variance against mean of AMPA-induced currents.