Sound localization with accuracy of a few millimetres: Hybrid Vocalization Localizer
Social interaction is commonplace in a vast number of species, forming the basis for mating and selection. Vocal communication is often an important part in social interaction. In rodents, the most common laboratory animal in neuroscience, vocal communication is hard to study because many vocalizations are ultrasonic, and it is hard to assign each vocalization to one of the interaction partners. Bernhard Englitz, Max Sterling and Ruben Teunisse developed a novel sound localization system which achieves a landmark improvement of accuracy, down to just a few millimetres.
Who is saying what?
A rigorous and meaningful study of vocal social interaction requires reliable assignment, to know 'who is saying what'. This information is important to understand the intentions and internal state of the animals, which can also signal distress and other emotional states. Previous methods have been too inaccurate and therefore likely assigned many vocalizations to the 'wrong' participant. Dr. Englitz and his team therefore set out to develop a localization system for ultrasonic vocalizations that can achieve the required accuracy for reliable assignment.
Dr. Englitz: “We developed a new sound localization system, Hybrid Vocalization Localizer (HyVL), which combines the advantages of two different types of microphones. It achieves a landmark improvement of accuracy, down to just a few millimetres, which forms the basis for a reliable detection and assignment of individual vocalizations. We applied the system to courtship interactions between two or three mice. In interactions of two mice, we find that female courtship vocalizations appear to be substantially rarer than previously shown. In interactions with three mice, we find that one of the males typically dominates the conversation, which is also reflected in the relative spatial location that he assumes in relation to the female mouse. “
Research in neuroscience and animal ethology in many different species will be able to benefit from this substantially improved accuracy and reliability. Further, the development of treatments for neurodevelopmental disorders often relies on monitoring the social interaction of mice or rats, and the use of vocalizations as a biomarker for normal social behaviour and distress could substantially benefit from an application of HyVL, because its costs are comparatively low.