Fig. 7.

γ frequency oscillations and seizure-like events are abolished by expansion of the extracellular space. A, γ oscillation and subsequent ictal discharge, evoked by paired stimuli, in Mg²⁺-free ACSF in a juvenile (P17) hippocampal slice before and after perfusion with hyperosmolar (30 mm sucrose added) ACSF. Field potential (fp) and membrane potential (ic) recordings from CA1 and CA3 strata pyramidale.B, Same recording as in A on an expanded time scale and taken from the trace as defined by the dotted rectangle during the γ oscillation.