Vocalization associated respiration patterns : thermography-based monitoring and detection of preparation for calling

Abstract

Vocal emission requires coordination with the respiratory system. Monitoring the increase in laryngeal pressure, needed for vocal production, allows detection of transitions from quiet respiration to vocalization-supporting respiration. Characterization of these transitions could be used to identify preparation for vocal emission and to examine the probability of it manifesting into an actual vocal production event. Specifically, overlaying the subject's respiration with conspecific calls can highlight events of call initiation and suppression, as a mean of signalling coordination and avoiding jamming. Here we present a thermal-imaging based methodology for synchronized respiration and vocalization monitoring of free ranging meerkats. The sensitivity of this methodology is sufficient for detecting transient changes in the subject's respiration associated with the exertion of vocal production. The differences in respiration are apparent not only during the vocal output but also prior to it, marking the potential time frame of the respiratory preparation for calling. A correlation between conspecific calls with elongation of the focal subject's respiration cycles could be related to fluctuations in attention levels or in the motivation to reply. This framework can be used for examining animals' capability for enhanced respiration control during modulated and complex vocal sequences, detect "failed" vocalisation attempts and investigate the role of respiration cues in the regulation of vocal interactions.