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

Figure 1

The sniff rate increases during cross-habituation in female wild type (WT) mice. A cotton tip odorized with phenyl ethanol (PE) or mouse urine as social odor (S) was presented 3 times during the habituation/cross-habituation test (HaXha). PE3 represents the 3rd presentation of PE and S1 the 1st presentation of S. The time exploring the odorant (OnTime) by WT mice (129 strain, ) was scored in real-time by Noldus video tracking system based on the standard criteria of nose proximity (<2 cm) and head orientation (<20°) to the odor source. The simultaneously plethysmographically measured sniff rate was measuring while exploring (OnFreq) and not exploring (OffFreq), as was the sniff amplitude (PeakMax_on and PeakMax_off, resp.). Increased exploration time during S1 shows cross-habituation and was accompanied by an increase in the sniff rate. OnFreq and OffFreq: sniff rate (Hz); PeakMax_on and PeakMax_off: sniff peak amplitude (standard deviations of -scored pressure signal). OnTime: odor object exploration time (s). All data are mean ± SEM.