Figure 4. CTZ induces spontaneous epileptiform activity in hippocampal CA1 region in in vivo recordings.

A, typical recordings showing that the evoked population spikes recorded from the CA1 pyramidal layer in urethane-anaesthetized rats transform from single peak at control (a) to multiple peaks (b and c, indicated by arrows) after CTZ injection (5 μmol, 5 μl, i.c.v.) (• indicates the stimulus artefact). B, a representative recording showing that spontaneous epileptiform bursts appeared ∼2 h after CTZ injection. In control conditions (a), there were only small baseline activities in CA1 pyramidal cells. Black dots indicate stimulus artefacts, the same as shown in Aa. After CTZ administration (b), large synchronized bursting activities appeared, with each large burst consisting of many smaller bursts of activities.