Fig. 9.
Glutamatergic involvement in spontaneous local field potential (LFP) generation in hippocampal CA1. (A) Schematic diagram of glutamatergic driving of γ rhythm in CA1 (adapted from Leung46 ). Apical dendritic γ activity in CA1 is driven by CA3 pyramidal cells (PYR) being recurrently inhibited by somatic interneurons (INT). CA3 receives glutamatergic (Glu) inputs from the dentate gyrus and entorhinal cortex. (B) Mean logarithmic power change from baseline (normalized to 0) with isoflurane dose (% vol) of the 70 to 100 Hz γ-band LFPs recorded in stratum radiatum, compared to the power (amplitude square) change of the normalized population excitatory postsynaptic potentials evoked by apical dendritic monosynaptic (mono pEPSP) or trisynaptic excitation (tri pEPSP). Error bar is one SD. Mono pEPSP power change is similar to radiatum LFP power change at 0.25% dose while tri-pEPSP power change is similar to radiatum LFP power change at 0.5 to 1.5% dose.