Isolation-Induced Ultrasonic Vocalization Calls (USVs) During 3-min Observation Time (n = 12–18 Per Treatment). (A) Number of USV calls of the pups isolated from their mother and littermates at days P3, P5, P9, and P11. Number of USVs was significantly reduced in lipopolysaccharide (LPS)-treated pups at day P3 (*P < .05). (B) Total duration of USV calls for each pup at days P3, P5, P9, and P11. Total duration of calls was significantly decreased in LPS-treated offspring at day P5 (***P < .001). (C) Mean duration of USVs for each pup at days P3, P5, P9, and P11. The mean duration of each was also reduced in LPS-treated offspring at day P5 (***P < .001). (D) Total number of USV calls during first isolation and second isolation right after brief maternal contact in prenatal saline- and LPS-treated offspring at day P9 (n = 12 per treatment). All the data are presented as mean ± standard error of the mean (*P < .05 and ***P < .001).