Fig. 2
From: Stroking stimulation of the skin elicits 50-kHz ultrasonic vocalizations in young adult rats
Responses of 50-kHz USVs to various stimulation. The number of 50-kHz USVs during ventral stroking (light gray column) was compared with that of other stimulations (dark gray column): light touching (a), stroking of the external genitalia (EG) (b), and swinging of the body (c). A comparison was also made between ventral stroking and holding without stroking (sham) (d). Ordinates, total number of 50-kHz USVs during 30-s stimulus period. **p < 0.01 ***p < 0.001, by paired t-test. n = 6