Fig. 4.

Incidence of hippocampal oscillations in individual regions was not significantly affected by manipulations of excitatory and inhibitory activity. Slow oscillations, ripples, and fast ripples were detected and defined as described in materials and methods. A, left: representative raw recording of a 0Mg-induced interictal spike in CA3 of a slice from an epileptic rat. Right: the same trace separated into the superimposed slow oscillation [with overlying suprathreshold population spike (arrowhead; spike and wave complex), which forms the “backbone” of the interictal spike], ripple, and fast ripple. Similar superimposition of ripples and fast ripples on the slow oscillations/spike and wave complexes were evident during SLE (not shown). Potential contamination of slow oscillation measures with stand-alone population spikes (∼7 ms in duration) was minimized by exclusion of putative events ≤10 ms in duration. B and C: the incidence of slow oscillations (left), ripples (center), and fast ripples (right) in individual hippocampal regions for the entire duration of the recording was not significantly different in 0Mg and 0Mg+BMI but was significantly higher in slices from epileptic (C) compared with control (B) rats in 0Mg+BMI. Bars indicate means ± SE; no. of slices/rats is indicated in parentheses. *Different from control, t-test, P < 0.05. **Different from control, t-test, P < 0.01. ^#Different from other recording conditions, ANOVA with Sidak post hoc comparison, P < 0.05. Scale bars in A, right, apply to all traces.