Figure 6.

PPR difference between PCs and BGs persists in paired recordings. A, Paired recording from a PC (Vh = -10 mV) and a BG (Vh = -65 mV) in 2 mm Ca²⁺, 1.3 mm Mg²⁺, and no CTZ. Paired stimuli (timing shown by arrowheads) were given at an interval of 150 msec; stimulus strength was set near threshold so that some failures of CF stimulation occurred. The CF-evoked responses either succeeded or failed at the same time in the two cells, indicating that the two cells share the same CF. B, Responses to paired-pulse stimulation from the same cells as in A, with the extracellular solution changed to 0.5 mm Ca²⁺, 2.8 mm Mg²⁺, and 200 μm CTZ. Notice that the PPR difference in the two cells persists at this condition. C, Summary of the PPR at an ISI of 150 msec in paired recordings in the same condition as in B. Open bar is for CF-PC EPSC, and filled bar is for CF-BG responses (n = 7 cell pairs; paired t test, ^*p < 0.001).