Figure 1.

Steps in extraction of activity episodes. Calculated frequency (34 kHz) is displayed in the figure heading. A. Sample trace (blue) and smoothed result of first Butterworth filter (red). B. Modified first derivative (black) and subsequent negated second derivative (blue). C. Identification of candidates that are local minima of second derivative (red, green) and final selected locations of activity episodes (green).

Del Giorno et al. BMC Neuroscience 2012 13(Suppl 1):P173   doi:10.1186/1471-2202-13-S1-P173