Ultrasonic vocalizations (UVs) are a useful and highly sensitive assessment tool for the study of numerous rodent models of teratology, toxicology and emotionality. While collecting UV data is a relatively straightforward task, analyzing it presents some challenges. These include defining the parameters for what constitutes a vocalization, the age of subject, and creating a situation in which the rats are likely to vocalize.

In this study, an automated system to detect and analyze UVs was developed for both pups and adult rats. The compressed 20-200 kHz output of an S-25 Bat Detector was digitally recorded (1000 Hz for adults, 5000 Hz for pups) and analyzed to detect UV start time, duration and relative intensity. Test sessions lasted 30 min for adults and 6 min for pups. With adults, UVs were initiated by an acoustic startle stimulus, and the study focused on UVs that were > 190 ms long, with > 120 ms between calls. With pups, UVs were initiated by maternal separation, and calls of interest were > 150 ms long, with > 60 ms between calls.

This technique has proven valuable in detecting subtle teratologic effects of ultrawide band radiofrequency radiation, genetic, gender and age variations in emotionality, and the effects of repeated handling.

The views, opinions and/or findings contained in this poster are those of the authors and should not be construed as official Department of the Air Force, Department of Defense or U.S. Government position, policy or decision, unless so designated by other documentation.

Paper presented at Measuring Behavior 2002 , 4^th International Conference on Methods and Techniques in Behavioral Research, 27-30 August 2002, Amsterdam, The Netherlands

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