The Habituation/Cross-Habituation Test Revisited: Guidance from Sniffing and Video Tracking

Figure 12

New combined proximity-velocity criterion improves HaXha exploration scoring in WT mice. To test the usefulness of the exploration criterion of the velocity >0.5 cm/s and distance <4 cm, the trials were scored accordingly (center) for sniff rate (Hz) when exploring (sniff_ON_di4Xve05) or not (sniff_OFF_di4Xve05) and exploration time (s; explore_ON_di4Xve05). The results of the standard criterion ( cm and angle < 20°) are shown on the left (same as Figure 1, left). Data were more robust upon removing sniff rates of mice with exploration time <1 sec (_B extension). The new criterion increased S1 exploration time (orange line) and decreased S2 and S3 exploration time variance (arrows), while retaining high sniff rates indicative of sniff-guided odorant exploration, leading to stronger statistical conclusions. The difference (%) in time bins meeting these two criteria was also assessed (% overlap; crit_diffpct_div4ve05) as well as between the Noldus distance-angle exploration marker output and the thresholded smoothed distance-angle score (crit_diffpct). ; ; (paired 1-sided -test versus S1).