Fig. 6

Ultrasonic vocalizations in adult mice. a Call rate in response to distinct olfactory and social stimuli. b Percent time vocalizing (Y-axis and circle symbols; WT: white circles, mdx: black circles) and time spent sniffing the stimuli (X-axis and horizontal histograms; WT: white bars, mdx: gray bars) in each test, as indicated below the X-axis. Tests are ordered from left to right from highest to lowest sniffing activity recorded in WT mice. Horizontal position of circles corresponds to the mean time sniffing. Overall, the largest amount of calls emitted by adult male mice was recorded during reciprocal interactions with freely moving females, then with anesthetized female and male–male interaction. Long time spent vocalizing was not systematically correlated with long time spent investigating stimuli. For example, exposition to females’ bedding resulted in large amounts of exploration (>40 % time sniffing) but relatively short time spent vocalizing compared to other testing situation associated with comparable time sniffing, such as in the male–female interaction. Ordering tests following the experimental test order does not reveal any progressive decrease or increase in exploration or USV production, suggesting that test order did not overcome responsiveness to social stimuli, but USV production was modulated by social context. c–j Histograms show the call duration (c), sequence rate (d), sequence duration (e), number of syllables or sequence elements (f), peak frequency at call start (g) and end points (h), and peak amplitude at start (i) and end points (j). U urine test, B bedding test, AF anesthetized female test, MF male–female interaction, MMwt interaction with a WT male, MMmdx interaction with an mdx male, Pfreq peak frequency, Pamp peak amplitude. *p < 0.05, Tukey post hoc test. ^# p < 0.05, main genotype effect in two-way ANOVA