Spontaneous SWRs in 490 mM horizontal hippocampal slices. Top: raw LFP traces (red and black) showing sharp waves from two recording locations in CA1 (filtered; 0.1 to 1500 Hz). Bottom: examples of ripples from the top trace are displayed on an expanded time scale (filtered; 30 to 1500 Hz). Note that in this 15 second section of recordings there are 26 SWRs, some large events (note 1,4,8) and some small events (note 6,7,9).