Abstract
A major mode of rodent communication occurs through ultrasonic vocalizations (USVs), which are influenced by environmental factors, mouse strain or genetic background and, importantly, by developmental stage. However, few studies have looked into the age-dependent evolution of spectral features of mouse USVs. Here, we report the existence of a novel vocalization, previously unreported, which we named “Fleeting” consisting of two acoustic elements produced with a narrow silent temporal interval between them. Strikingly, this vocalization pattern was extinguished after the second postnatal week, and this temporal pattern was associated with increased emission of Complex vocalizations, by gradual loss of the inter-element interval, suggesting a maturation process occurring at this time point. Importantly, the Fleeting vocalization was analyzed in a mouse model (Tsc2+/-) of Autism Spectrum Disorder (ASD), and showed an abnormal persistence, in particular in females which presented delayed conversion of Fleeting into Complex vocalizations compared with males. The identification of this novel vocalization represents an important insight into the maturation of mouse vocal repertoire and may be used as a developmental milestone in studies on neurodevelopmental disorders with communication impairments.
Regional brain volume differences between males with and without autism spectrum disorder are highly age-dependent
