Figure 1: Stereotypic movement The duration (A) and frequency (B) of repetitive bipedal circling of an EGFtreated cynomolgus monkey (6 years old male) with spinning its neck was measured for 60 min and averaged in 3 time observations (filled bars). Video observations were done before and after risperidone treatment (RIS; 0.05 and 0.10 mg/kg: dotted bars). The same measurement was done for a reference monkey (Ref; open bars). Bars represent mean ± SEM. **P<0.01, compared with a reference monkey and +P<0.05, compared between before and after risperidone treatment of an EGF monkey, both by two-tailed t-test. Note; risperidone treatment conversely resulted in a non-significant trend of an increase in a mean duration of one occurrence of repetitive bipedal circling (F3,11=2.57, P=0.127).