Repetitive behaviors and restricted interests are defining traits of autism. While the exact cause of these behaviors is unknown, several studies suggest they may originate in the striatum, a cluster of neurons in the brain that helps initiate and execute movements. Over the past twenty years, the scientific understanding of the striatum has increased, and some scientists now believe this region of the brain may be connected to the social difficulties experienced by many people with autism. Ann Graybiel, professor of brain and cognitive sciences at the Massachusetts Institute of Technology, explains that the traditional view is that the striatum inhibited or excited movement. Now, researchers understand that it “might also be dealing with mood, motivation, approaching good or avoiding bad, reward-based learning — all kinds of things like that.” According to a Spectrum News report, the striatum also appears to play an important role in learning to make eye contact, and determining which sensory information warrants attention. This view is based on studies that have traced the striatum’s connection to the parts of the brain that process sensory information, thoughts, feelings, and emotions. The striatum’s structure and functions might also be impaired by mutations in many genes linked to autism.
The striatum is part of the basal ganglia, clusters of neurons located deep in the center of the brain. The striatum processes signals from the cerebral cortex about desired goals, and prompts neurons in the basal ganglia to initiate actions to achieve those goals. The striatum was first linked with autism in 1978, when scientists reported rhythmic and tic-like gestures in children with autism, unusual posture and gait, and an unusual, upward extension of the big toes, known as “striatal toes.” These problems are often observed in people and lab animals with a damaged striatum. The link between autism and the striatum has also been supported by brain imaging studies, which have found that some parts of the striatum are enlarged in people with autism. As noted in Spectrum’s report, people with autism generally show low activity in the striatum when completing tasks that offer a social reward. Difficulties with processing social reward may explain why people with autism are often uninterested in social interaction. Genetic studies have found that many of the genes mutated in people with autism are highly expressed in the striatum. Dave Sulzer, professor of neurobiology at Columbia University, and his colleagues are focusing on a gene called mTOR, which is unusually active in children with autism, and the role that it plays in the striatum. Sulzer noted that the striatum’s structure is “very complicated,” and that “autism is a developmental [condition], so people should be looking at development.” Source: https://www.spectrumnews.org/news/striatum-the-brains-reward-hub-may-drive-core-autism-traits/