Our group has just published on line new results on a mouse model of the maternal infection risk factor for autism. In this model, pregnant mice are given an immune activation to imitate an infection such as the flu. The new results show that the very young and adult offspring of these mice display the cardinal behavioral symptoms of autism: increased repetitive/stereotyped behaviors and deficits in communication and social interaction. The repetitive behaviors that are monitored are self-grooming and marble burying. The social interaction test asks if the mice prefer interacting with a another mouse versus a novel object. The verbal communication test involves recording ultrasonic vocalizations (USVs). These vocalizations cannot be heard by humans but can be recorded with special equipment (“bat detector”). [see Figure 6.2 in the book for an example of these recordings and a comparison with recordings of bird song] Senior postdoctoral fellow Natalia Malkova and colleagues Collin Yu and Elaine Hsiao found that the offspring of immune-activated mothers emit fewer USVs, and their calls are somewhat different in character as well. Thus, there are quantitative and qualitative differences in their USVs compared to control mice. These behavioral findings support our earlier assessment of postmortem brains, which showed that the offspring of infected or immune-activated mothers display a neuropathology commonly found in autism, a spatially distinct deficit in Purkinje cells.