Fig. 3.

Electrophysiological results. (A) Assessment of hippocampal long-term potentiation. The time course of CA1 fEPSPs is illustrated. The induction protocol (TBS) was delivered at time 0. In WT mice, LTP magnitude was reduced after FS. In 3xTg, FS failed to alter LTP magnitude. *, P < 0.05. Inset, specimen recording of fEPSPs recorded immediately before and 30 min after TBS in a slice obtained from the Tg/FS group. Scale bars; 3 ms, 0.1 mV. (B) Assessment of excitability in cingulate cortex pyramidal cells. Frequencies of action potentials elicited by injecting depolarizing currents of various intensities are plotted. The frequency is significantly higher in WT/FS group neurons than in WT group neurons, indicating that FS induced hyperexcitability in WT mice. The same is true in 3xTg mice. Inset, specimen recording of spikes evoked in a neuron obtained from a Tg/FS mouse by an injection of 500 ms-long current (500 pA). The majority of error bars are too short to be clearly seen. Scale bars; 20 mV, 50 ms. **, P < 0.005.