Results from EPSC variance–mean analysis under conditions of high release probability
| Cell | Ionic conditions (mm) | Fit of parabola | N | q(pA) | qinitial slope (pA) |
|---|---|---|---|---|---|
| Nov03A | 10 Ca, 1 Mg | + (sat) | 467 | 15.6 | 7.0 |
| Dec17B | + | 290 | 17.9 | 6.3 | |
| Feb19A | + | 675 | 15.2 | 6.4 | |
| Feb19B | − | 2.8 | |||
| Mar04A | + | 130 | 30.9 | 4.6 | |
| Mar04B | + (sat) | 845 | 7.5 | 4.4 | |
| Mar08A | 15 Ca, 0 Mg | − | 8.7 | ||
| Mar08B | + | 510 | 21.7 | 6.0 | |
| Mar10A | + (sat) | 576 | 9.4 | 3.1 | |
| Mar11B | + | 1995 | 6.9 | 2.6 | |
| Average ± SD | 686 ± 573 | 15.6 ± 8.1 | 5.2 ± 2.0 |
All experiments were done in the presence of 70 nmNBQX. Extracellular Ca2+ and Mg2+concentrations were as indicated. The goodness of parabola fits to EPSC variance–mean data is indicated, with + and + (sat) denoting cases in which parabola fits could be obtained. In case of + (sat), the EPSC variance–mean plot showed a saturating behavior without going through a maximum, as in the example of Figure5C. The values of q andqinitial slope are quantal sizes obtained from parabola fits and line fits to the initial part of EPSC variance–mean plots, respectively. Both were corrected for the CV of mEPSC amplitude distributions (Eq. 4).