Fig. 4.

Repetitive stimulation-induced epileptiform bursts were associated with a negative DC shift in field-potential and depolarization. A and B: simultaneous whole cell (WC, top) and field-potential (FP, bottom) recordings showing changes in membrane potential and the baseline field-potential during 5-Hz perforant-path repetitive stimulation. In slices from rats with kainate-induced epilepsy, repetitive stimulation caused a DC shift in field potential (B, bottom), which was absent or negligible in slices from control rats (A, bottom). The initial, middle, and later responses (●) to repetitive stimulations in both groups were shown in expanded scale below as indicated ↓. Repetitive stimulation caused a modest depolarization in dentate granule cells in slices from control rats (A, top) and appeared to cause a larger depolarization in granule cells in slices from rats with kainate-induced epilepsy (B, top). - - -, the baseline voltage levels. Scale bars in A apply to B.