FIGURE 3.

Effects of muscarinic receptor activation by carbachol in the dentate gyrus. Data are shown prior to (control) and during (carbachol) bath application of 10 mM carbachol. Stimulus-evoked fEPSPs (ENT and ARR combined, n = 22 animals) were suppressed by carbachol (a1) while simultaneously-recorded population spikes were unaffected (a2), however, there were no significant differences between ENT (n = 10) and ARR (n = 12) groups in these measures (b1, b2; p > .05). The high variance in the ENT control group (b1) was largely due to one cell, however, it was not a significant outlier (Grubbs’ test, p > .05). Paired pules ratio (PPR) of EPSPs was not affected by carbachol and did not differ between cells from ENT (n = 9) and ARR (n = 11) groups (c1; p > .05). By contrast, PPR of the population spike was significantly increased by carbachol in both ENT and ARR groups, although the effect was significantly reduced in cells from ARR animals (c2). ** Indicates stimulus (0.2–0.7 mA in panel c1), ISIs (40–100 ms in panel c2) that differed significantly between ENT and ARR groups under carbachol treatment (p < .01)