Fast neuronal network oscillations in the gamma range (~30-80 Hz) have been implicated in higher brain functions such as memory formation and sensory processing. In hippocampal slice preparations gamma oscillations can be evoked by acetylcholine, which mimics cholinergic input from the septum. In this study, the O2 and energy demands of gamma oscillations were determined in acute mouse slices and in rat organotypic slice cultures by applying electrophysiology, O2 sensor microelectrodes and fluorescence imaging (NAD(P)H, FAD). It was shown that gamma oscillations decrease...