Cd ²⁺ blocks mEPSC bursts. (A) A recording in control solution (3 Ca_o/20 K_o) displaying two bursts (green; dotted areas and expanded traces below), and after addition of 100 μM Cd²⁺ (black trace, containing one burst). (B) Summary data showing that Cd²⁺ reduces overall mEPSC frequency (left), burst frequency (center), and percentage time of bursting (right). (C and D) Comparison of IEI histograms in linear (C; bin size: 50 ms) and logarithmic (D; bin size: 0.2 log unit) coordinates before and after addition of 100 μM Cd²⁺ (n = 5 cells). P values represent the results of paired t tests for mEPSC frequency, burst frequency, and percent bursting time in Cd²⁺ vs. control in B, and that of a paired-test comparison between the first 50 ms bin of IEI histograms in Cd²⁺ vs. control (C). Data obtained from n = 5 cells from 4 animals.