Hyperlocomotion and deficits in the PPI of PACAP−/− mice were normalized by risperidone treatment. (a) Locomotor activity in wild-type and PACAP−/− mice that received 0.1 mg/kg risperidone (RIS) or saline. n=6 per group. (b) Representative locomotor patterns of saline- or 0.1 mg/kg risperidone-treated wild-type and PACAP−/− mice during 25–30 min of a 60 min recording in an open field test. (c) PPI levels induced by a 77 dB prepulse in wild-type and PACAP−/− mice after pretreatment with risperidone (0.1 mg/kg) or saline. Numbers of animals for experiments are shown in parentheses. Data are given as means±s.e.m. *P<0.05, **P<0.01, ***P<0.001, compared to wild-type. #P<0.05, ##P<0.01, compared with saline in PACAP−/− mice.