Effects of lurasidone on ketamine-induced joint visual attention dysfunction as a possible disease model of autism spectrum disorders in common marmosets.

Infants with autism have difficulties performing joint visual attention (JVA), defined as following another person's pointing gesture and gaze. Some non-human primates (NHPs) can also perform JVA. Most preclinical research on autism spectrum disorders (ASD) has used rodents as animal models of this social interaction disorder. However, models using rodents fail to capture the complexity of social interactions that are disrupted in ASD. Therefore, JVA impairment in NHPs might be a more useful model of ASD. The aim of this study was to develop an appropriate and convenient ASD model with common marmosets. We first tested whether marmosets were capable of performing JVA. Subsequently, we administered ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, to induce JVA impairment and investigated the effects of lurasidone, a newer antipsychotic agent, on the JVA impairments. An apparatus was constructed using 4 white boxes, which were attached to the corners of a frame. All boxes had a hinged door, and marmosets could easily obtain a reward by pushing the door. An experimenter pointed and gazed at the boxes to inform the marmosets which box contained the reward. Their behavior was scored according to the number of incorrect choices. The JVA score was significantly higher in the cued vs. uncued tasks. Ketamine significantly decreased the JVA score, but lurasidone significantly reversed this effect. These findings suggest that this experimental system could be a useful animal model of neuropsychiatric disorders characterized by NMDA-receptor signaling, including ASD, and that lurasidone might be effective for some aspects of ASD.