Ultrasonic Sound Effects Mice – University Case Study

Summary

In an aversive ultrasound-induced defense paradigm, mice displayed a major increase in ‘wild’ escape-like behaviors. Study keywords include depression; anxiety; defense behaviors. (Page 1  )

Mice were tested for their innate fear reactions to a train of ultrasonic stimuli (US) … Animals were placed one per cage for at least 1 week before testing. In brief, 100 ms frequency sweeps between 17 and 20 kHz, 85 dB, alternately ON 2 seconds and then OFF 2 seconds for 1 min were delivered into the home cage (10 × 29 cm²) after a 3-min baseline period. Flight reactions triggered during ON periods were measured as the number of running events from one side of the cage to the other followed by behavioral arrest, whereas the percentage time ‘freezing’ to the US stimuli was quantified by sampling events of complete immobility (except respiration) every 4 during the OFF period. These defense behaviors were measured from a video file by an observer unaware of mouse genotype. (Page 3  )

This diagram shows the inverse relationship between brain tissue levels of 5-HT and aversive ultrasound-induced flight behaviors in mice. There was an enhancement of flight behaviors in reaction to the aversive ultrasound (1 min fast sweep 17–20 kHz, 85 dB) in mice compared with control mice, which was reversed by a chronic treatment with pargyline. (Page 9  )