Figure 4.

Quantal amplitude does not depend on presynaptic Fmr1 expression. A–D, Examples of uEPSCs before (A, B) and after (C, D) wash-in of CdCl₂ to lower the probability of release to the point where it is assumed that isolated single quanta are observed. Note the decreased uEPSC amplitude and increased failures after wash-in. Black and gray lines indicate successes and failures, respectively. Calibrations: (in A) A, B, 50 mV, 20 pA; 2 ms; (in C) C, D, 10 pA, 2 ms. E, uEPSCs were averaged during CdCl₂ application (excluding failures) to obtain an estimate of the average quantal amplitude. This was unchanged. F, uEPSC amplitude before wash-in was smaller in the KO/WT pairs in these experiments. *p < 0.05. uEPSC traces are a running average of three samples.