Disturbances In Autism Spectrum Disorder Research Articles

Parent–child DRD4 genotype as a potential biomarker for oppositional, anxiety, and repetitive behaviors in children with autism spectrum disorder

The primary objective of the present study was to examine whether a combination of parent-child DRD4 genotypes results in more informative biomarkers of oppositional, separation anxiety, and repetitive behaviors in children with autism spectrum disorder (ASD). Based on prior research indicating the 7-repeat allele as a potential risk variant, participants were sorted into one of four combinations of parent–child genotypes. Owing to the possibility of parent-of-origin effects, analyses were conducted separately for mother–child (MC) and father–child (FC) dyads. Mothers completed a validated DSM-IV-referenced rating scale. Partial eta-squared (ηp 2) was used to determine the magnitude of group differences: 0.01–0.06 = small, 0.06–0.14 = moderate, and > 0.14 = large. Analyses indicated that children in MC dyads with matched genotypes had the least (7−/7−) and most (7+/7+) severe mother-rated oppositional-defiant (ηp 2 = 0.11) and separation anxiety (ηp 2 = 0.19) symptoms. Conversely, youths in FC dyads with matched genotypes had the least (7−/7−) and most (7+/7+) severe obsessive-compulsive behaviors (ηp 2 = 0.19) and tics (ηp 2 = 0.18). Youths whose parents were both noncarriers had less severe tics than peers with at least one parental carrier, and the effect size was large (ηp 2 = 0.16). There was little evidence that noncarrier children were rated more severely by mothers who were carriers versus noncarriers. Transmission Disequilibrium Test analyses provided preliminary evidence for undertransmission of the 2-repeat allele in youths with more severe tics ( p = 0.02). Parent genotype may be helpful in constructing prognostic biomarkers for behavioral disturbances in ASD; however, findings are tentative pending replication with larger, independent samples.

Impaired Error Monitoring and Correction Function in Autism

INTRODUCTION: Error monitoring and correction is one of the executive functions and is important for effective goal directed behavior. Deficient executive functioning, including reduced error monitoring ability, is one of the typical features of such neurodevelopmental disorders as autism, probably related to perseverative responding, stereotyped repetitive behaviors, and an inability to accurately monitor ongoing behavior. Our prior studies of behavioral and event-related potential (ERP) measures during performance on visual oddball tasks in high-functioning autistic (HFA) children showed that despite only minor differences in reaction times HFA children committed significantly more errors. METHODS: This study investigated error monitoring in children with autism spectrum disorder (ASD) with response-locked event-related potentials - the Error-related Negativity (ERN) and Error-related Positivity (Pe) recorded at fronto-central sites. The ERN reflects early error detection processes, while the Pe has been associated with later conscious error evaluation and attention re-allocation. Reaction times (RT) in correct trials and post-error slowing in reaction times were measured. In this study fourteen subjects with ASD and 14 age- and IQ- matched controls received a three-category visual oddball task with novel distracters. RESULTS: ERN had a lower amplitude and longer latency in the ASD group but was localized in the caudal part of anterior cingulate cortex (ACC) in both groups. The Pe component was significantly prolonged in the ASD group but did not reach significance in amplitude differences compared to controls. We found significant post-error slowing in RTs in controls, and post-error acceleration in RTs in the ASD group. CONCLUSIONS: The reduced ERN and altered Pe along with a lack of post-error RT slowing in autism might be interpreted as insensitivity in the detection and monitoring of response errors and a reduced ability of execute corrective actions. This might result in reduced error awareness and failure in adjustment when dealing with situations where erroneous responses may occur. This deficit might be manifested in the perseverative behaviors often seen in individuals with ASD. The results are discussed in terms of a general impairment in self-monitoring and other executive functions underlying behavioral and social disturbances in ASD.

Abnormal activation of the social brain during face perception in autism.

ASD involves a fundamental impairment in processing social-communicative information from faces. Several recent studies have challenged earlier findings that individuals with autism spectrum disorder (ASD) have no activation of the fusiform gyrus (fusiform face area, FFA) when viewing faces. In this study, we examined activation to faces in the broader network of face-processing modules that comprise what is known as the social brain. Using 3T functional resonance imaging, we measured BOLD signal changes in 10 ASD subjects and 7 healthy controls passively viewing nonemotional faces. We replicated our original findings of significant activation of face identity-processing areas (FFA and inferior occipital gyrus, IOG) in ASD. However, in addition, we identified hypoactivation in a more widely distributed network of brain areas involved in face processing [including the right amygdala, inferior frontal cortex (IFC), superior temporal sulcus (STS), and face-related somatosensory and premotor cortex]. In ASD, we found functional correlations between a subgroup of areas in the social brain that belong to the mirror neuron system (IFC, STS) and other face-processing areas. The severity of the social symptoms measured by the Autism Diagnostic Observation Schedule was correlated with the right IFC cortical thickness and with functional activation in that area. When viewing faces, adults with ASD show atypical patterns of activation in regions forming the broader face-processing network and social brain, outside the core FFA and IOG regions. These patterns suggest that areas belonging to the mirror neuron system are involved in the face-processing disturbances in ASD.