Ultrasonic vocalization (UV) as a measure of social memory was investigated
in female mice. UVs emitted by a resident female in the presence of a same
-sex partner were measured during a 3-min, pretest social interaction. In a
second 3-min test session, mice were reexposed to the familiar partner or
presented with a novel partner. In the first case, there was a decline in U
Vs emitted by resident mice when the intervals between the 2 sessions were
15, 30, or 60 min. After 24 hr. this effect disappeared. In contrast, with
a novel female partner, the number of UVs remained unchanged. Scopolamine (
0.05 mg/kg ip) disrupted this memory process: Drug-treated females did not
show the expected decrease in UVs when reexposed to the familiar female aft
er 30 min. This study provides behavioral and pharmacological evidence that
ultrasonic calls can be used as a measure of social memory in female mice.