Fig. 5.

Antagomir effects on hippocampal biophysics in naïve animals. (A) Stimulus–response curves. We stimulated the Schaffer collateral pathway in the hippocampus and recorded the population synaptic response in CA1 stratum radiatum (Left schematic). Robust responses were observed in all treatment groups (Middle Left) and no significant differences in excitability were seen between groups (Right; mixed ANOVA, P > 0.05). (B) Paired-pulse facilitation. We used the same electrode configuration as A but this time delivered two pulses (generating a response that was 30% of the maximum) at varying intervals. Robust facilitation was seen in all groups (B, representative raw data for 50-ms stimulation interval) with no clear differences between groups (C, mixed ANOVA, P > 0.05). (D) Single cell biophysics. We made current clamp recordings from CA1 pyramidal neurons and injected a current step protocol (−100 to +400 pA, 25-pA increments, 100-ms step duration). Raw data show the threshold action potential from each neuron. Total numbers of rats and cells used for each group are listed. (E) There were no differences in any passive properties (resting membrane potential [RMP] and input resistance scatterplots) or in properties of the threshold action potentials (all one-way ANOVA with Bonferroni post hoc test, P > 0.05).