Extracellular Calcium Controls the Expression of Two Different Forms of Ripple-Like Hippocampal Oscillations

摘要: Hippocampal high-frequency oscillations (HFOs) are prominent in physiological and pathological conditions. During ripples (100-200 Hz), few pyramidal cells fire together coordinated by rhythmic inhibitory potentials. In the epileptic hippocampus, fast (>200 Hz) reflect population spikes (PSs) from clusters of bursting cells, but HFOs ripple range vastly intermixed. What is meaning this frequency range? determines expression different HFOs? Here, we used concentrations Ca(2+) a (1-3 mM) to record local field potentials single hippocampal slices normal rats. Surprisingly, found that sole manipulation results emergence two forms reminiscent recorded vivo rats, respectively. We scrutinized cellular correlates mechanisms underlying these combining multisite, single-cell paired-cell recordings prepared rat reporter line facilitates identification GABAergic cells. major effect extracellular modulating intrinsic excitability disynaptic inhibition, critical factors shaping network dynamics. Moreover, locally concentration an environment had similar on cell excitability, Therefore, HFO band reflects firing dynamics networks.