Autism has become a more frequently diagnosed disorder than ever before. There are three behavioral domains that psychologists use to diagnose autism: repetitive behavior, deficits in social interaction and communication (Lewis, Tanimura, Lee, & Bodfish, 2006). Repetitive behavior is operationally defined as the broad class of behaviors related by repetition, rigidity and invariance (Lewis et al., 2006). When it comes to repetitive behaviors in autism and brain function, there is not much research done. Importance is obvious for this topic because if researchers find what in the brain causes the repetitive behavior, they could treat it. Some of the repetitive behavior in children with autism is debilitating and they would benefit from treatment for the specific symptoms.
Caudate volume has been associated with repetitive behavior in different research (Hollander et al., 2005 and Rojas et al., 2006). In a study done by Hollander et al. (2005), they took magnetic resonance image (MRI) of the brain of seventeen subjects with autism. They discovered that the right caudate nucleus was higher in volume in autistic subjects than in the control subjects. In another study, they too, did MRI’s of the autistic subjects’ brains and control subjects without autism. The researchers found significant correlations between volumes of the caudate nucleus and a measure of repetitive behaviors (Rojas et al., 2006). In this study, they used the Autism Diagnostic Interview (ADI-R) test and compared them to the brain images. This comparison showed that the caudate nucleus volume and the Repetitive and Stereotyped Behavior Domain had a positive correlation. The caudate nucleus is part of the cortical-basal ganglia and in a study by Lewis et al. (2006), they found results of alterations in this area in the growth of repetitive behaviors. The caudate nucleus was found to be smaller in stereotyped subjects of this study. Other researchers (O’Hearn, Asato, Ordaz, & Luna, 2008) found similar results when asking subjects to complete a mental rotation task. They found that the caudate nucleus was less activated during the task.
The different gyri in the brain have also been associated with the differences in brain function dealing with repetitive behavior in patients with autism. Rojas et al. (2006) found when they did MRI’s on subjects with autism the grey matter volume in the left and right medial frontal gyri, left middle temporal and pre-central gyri, right fusiform gyrus, and the right post-central gyrus increased. This same study also showed a negative correlations in the superior temporal gyri and the left post-central gyrus compared to the ADI-R. O’Hearn et al. (2008) also did a study in which they found less activation in the right inferior frontal gyrus and the right medial frontal gyrus with patients with autism related to their repetitive behavior.
The putamen volume is also differing in patients with autism exhibiting repetitive behavior. In a study done...