SPWs are large amplitude negative polarity deflections (40–100 ms) in CA1 stratum radiatum....
-- Buzsáki, G. (2015). Hippocampal sharp wave-ripple: A cognitive biomarker for episodic memory and planning: HIPPOCAMPAL SHARP WAVE-RIPPLE. Hippocampus 25, 1073–1188.
40-100 ms cycles correspond to 10-20 Hz