A hallmark symptom of autism spectrum disorders is impairment in social interactions, yet little is known about the neural mechanisms underlying this deficit. In contrast to autism, Williams-Beuren syndrome involves enhanced sociability. The syndrome affects many systems, including the motor, sensory, language, cognitive, emotional and social systems. It is caused by a chromosomal microdeletion. Most individuals with the disorder have relatively preserved language skills in conjunction with high sociability, which are quite opposite from the salient features of autism.

In daily life, people often experience activation of multiple sensory systems at the same time. For example, speech perception and social behavior rely on an interaction between the auditory and visual systems (i.e., listening to a person’s voice while watching his lips move). Similarly, as people interact with the environment, signals from the visual and balance (vestibular) systems must work together. This process is known as ‘multisensory integration,’ and when it’s not functioning well, as in autism, life becomes challenging.

Pavel Osten and his colleagues at Cold Spring Harbor Laboratory in New York studied mouse brain circuits that mediate social and other innate behaviors, such as aggression and sexual behaviors. The researchers used a novel method called serial two-photon tomography and computational whole-brain analysis of the induction of the immediate early gene c-FOS, one of a class of genes induced by neuronal activity and a molecular marker of neuronal activation.

Autism spectrum disorders are prevalent neurodevelopmental disorders that involve early postnatal symptoms and regression of developmental milestones within the first few years of life. Healthy brain development, particularly in regions of the cortex involved in sensory and cognitive processing, depends on periods of rapid cellular growth known as critical periods. Connections between neurons, or synapses, are formed and refined during these time-restricted windows in a process known as synaptic plasticity, which is key to the proper functioning of the brain. Mouse models of autism show delays in specific developmental milestones: Synaptic connections remain in an immature state past the normal closure of the critical period, and there is a shift in the window for when synapses can be modified by experience.

We lack effective tools for assessing behavior and cognition in the most severely impaired individuals with autism. Jeffrey Munson and his colleagues at the University of Washington are addressing this need through the application of motion-controlled gaming technologies.

The younger siblings of children diagnosed with autism are at an increased risk for autism themselves. By studying these at-risk babies, we can better understand the development of the condition and this, in turn, may lead to more effective early treatments. It remains challenging, however, to study brain function in a safe and effective way in young babies. Mark Johnson and his colleagues at the University of London have been developing a new method of brain imaging called functional near-infrared spectroscopy (fNIRS), which involves weak beams of light that are absorbed differently in active vs. inactive parts of the brain.

Some forms of autism spectrum disorder include stereotyped, repetitive motor behaviors. The cerebellum, a part of the brain that helps individuals to coordinate complex movements, appears to be physically altered in some people with autism. What’s more, several genes whose mutations have been linked to autism exert their actions strongly in the cerebellum. Together, these observations suggest that the electrical and chemical signals transmitted by neurons in the cerebellum may be disrupted, leading to some of the pathological motor behaviors associated with autism spectrum disorder.

As the number of genetic anomalies associated with autism continues to escalate, demand grows to understand the mechanisms through which these genes affect brain function and behavior. Mouse models engineered to express autism susceptibility genes are critical for achieving this goal, but their utility depends on behavioral assessment methods that have limited reliability, comprehensiveness, sensitivity and throughput.

Copy number variation (CNV) of the 16p11.2 region is associated with numerous developmental problems, including an increased risk for autism. Little is known about how the function of the cortex differs between individuals with 16p11.2 deletions and duplications, and between those who have autism and those who do not. Charles Nelson and his colleagues set out to investigate these knowledge gaps in a sample of children with 16p11.2 CNVs using electrophysiological methods to assess cortical processing.