Altered USV production in old Tau.P301L mice.

<p>A1- Rough USV spectrographic display with frequency and time scales in kHz and ms, respectively. A2 – As above but showing the tags (Tg, white dots) placed at slope changes in frequency on the rough USV and the analyzed USV parameters: duration of USV (Dur_(USV)), frequency at tags (Freq_(USV)), max and min Freq_(USV) (RangeFreq), complexity (number of segments delimited by tags), and number of USV produced per min of recording (Nb_(USV)). The total time of USV per min (totT_(USV)) was obtained by summation of individual Dur_(USV). B – Columns in histograms show Dur_(USV) (expressed in ms) in Tau.P301L (black columns) and FVB/N (white columns) mice at age 4–5 months and 8–10 months (young and old mice, respectively). Note the significant reduction of Dur_(USV) in old Tau.P301L mice. C – As in B but for Nb_(USV) (expressed in USV per min). Note the drastic reduction of Nb_(USV) in old Tau.P301L mice. D – As in B but totT_(USV) (expressed in s per min of recording). Note the significant and drastic reduction of totT_(USV) in old Tau.P301L mice. * indicates a significant inter-strain difference at a given class of age and $ a significant age-related difference for a given strain; ns, non significant inter-strain difference.