Frequency-specific age-related changes in the amplitude of spontaneous fluctuations in autism.

Background: Autism spectrum disorder is characterized by atypical developmental changes during brain maturation, but regional brain functional changes that occur with age and across different frequency bands are unknown. Therefore, the current study aimed to explore potential age and frequency band-related changes in the regional brain activities in autism. Methods: A total of 65 participants who met the DSM-IV criteria for autistic disorder and 55 typically developed (TD) participants (both age 6-30 years) were recruited in the current study. The two groups were matched in age (t=-1.314, P=0.191) and gender (χ2=2.760, P=0.097). The amplitude of low-frequency fluctuations (ALFF) was employed to explore the effect of development on spontaneous brain activity in individuals with autism and in TD participants across slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), and slow-3 (0.073-0.1 Hz) frequency bands. The diagnosis-by-age interaction effect in the whole brain voxels in autism and TD groups was investigated. Results: Autism individuals showed significantly higher ALFF in the dorsal striatum in childhood (Caudate cluster: t=3.626, P=0.001; Putamen cluster: t=2.839, P=0.007) and remarkably lower ALFF in the dorsal striatum in adulthood (Caudate cluster: t=-2.198, P=0.038; Putamen cluster: t=-2.314, P=0.030) relative to TD, while no significant differences were observed in adolescence (all P>0.05). In addition, abnormal ALFF amplitudes were specific to the slow-4 (0.027-0.073 Hz) frequency band in the clusters above. Conclusions: The current study indicated abnormal development patterns in the spontaneous activity of the dorsal striatum in autism and highlighted the potential role of the slow-4 frequency band in the pathology of autism. Also, the potential brain mechanism of autism was revealed, suggesting that autism-related variations should be investigated in a specific frequency.

Developmental brain structural atypicalities in autism: a voxel-based morphometry analysis.

BACKGROUND: Structural magnetic resonance imaging (sMRI) studies have shown atypicalities in structural brain changes in individuals with autism spectrum disorder (ASD), while a noticeable discrepancy in their results indicates the necessity of conducting further researches. METHODS: The current study investigated the atypical structural brain features of autistic individuals who aged 6-30 years old. A total of 52 autistic individuals and 50 age-, gender-, and intelligence quotient (IQ)-matched typically developing (TD) individuals were included in this study, and were assigned into three based cohorts: childhood (6-12 years old), adolescence (13-18 years old), and adulthood (19-30 years old). Analyses of whole-brain volume and voxel-based morphometry (VBM) on the sMRI data were conducted. RESULTS: No significant difference was found in the volumes of whole-brain, gray matter, and white matter between the autism and TD groups in the three age-based cohorts. For VBM analyses, the volumes of gray matter in the right superior temporal gyrus and right inferior parietal lobule in the autism group (6-12 years old) were smaller than those in the TD group; the gray matter volume in the left inferior parietal lobule in the autism group (13-18 years old) was larger than that in the TD group; the gray matter volume in the right middle occipital gyrus in the autism group (19-30 years old) was larger than that in the TD group, and the gray matter volume in the left posterior cingulate gyrus in the autism group was smaller than that in the TD group. CONCLUSION: Autistic individuals showed different atypical regional gray matter volumetric changes in childhood, adolescence, and adulthood compared to their TD peers, indicating that it is essential to consider developmental stages of the brain when exploring brain structural atypicalities in autism.

Atypicalities in the developmental trajectory of cortico-striatal functional connectivity in autism spectrum disorder.

LAY ABSTRACT: Autism spectrum disorder has long been conceptualized as a disorder of "atypical development of functional brain connectivity (which refers to correlations in activity levels of distant brain regions)." However, most of the research has focused on the connectivity between cortical regions, and much remains unknown about the developmental changes of functional connectivity between subcortical and cortical areas in autism spectrum disorder. We used the technique of resting-state functional magnetic resonance imaging to explore the developmental characteristics of intrinsic functional connectivity (functional brain connectivity when people are asked not to do anything) between subcortical and cortical regions in individuals with and without autism spectrum disorder aged 6-30 years. We focused on one important subcortical structure called striatum, which has roles in motor, cognitive, and affective processes. We found that cortico-striatal intrinsic functional connectivities showed opposite developmental trajectories in autism spectrum disorder and typically developing individuals, with connectivity increasing with age in autism spectrum disorder and decreasing or constant in typically developing individuals. We also found significant negative behavioral correlations between those atypical cortico-striatal intrinsic functional connectivities and autistic symptoms, such as social-communication deficits, and restricted/repetitive behaviors and interests. Taken together, this work highlights that the atypical development of cortico-subcortical functional connectivity might be largely involved in the neuropathological mechanisms of autism spectrum disorder.

Health-related risky behaviors and their risk factors in adolescents with high-functioning autism.

BACKGROUND: Health-related risky behaviors generally refer to behaviors that have a negative impact on health and quality of life. Health-related risky behaviors in adolescents with high-functioning autism (HFA) have not been well understood so far. Adolescents with HFA may have more health-related risky behaviors than neurotypical adolescents. AIM: To investigate health-related risky behaviors and their risk factors with HFA. METHODS: This is an observational study. Our study enrolled 110 adolescents aged 12-19-years-old meeting Diagnostic and Statistical Manual of Mental Disorders 4th edition criteria for HFA. They were recruited from Peking University Sixth Hospital. There were also 110 age, sex and nationality matched controls enrolled who came from a public school in Beijing, China. Both groups completed the Adolescents Health-related Risky Behavior Inventory. Nonparametric tests were carried out for comparison of the Adolescents Health-related Risky Behavior Inventory scores between the two groups. Expression recognition, the Inventory of Subjective Life Quality for Child and Adolescent, Chinese Wechsler Intelligence Scale for Children, Wechsler Intelligence Scale for Adult-Chinese Revised, Theory of Mind test and Autism Spectrum Screening Questionnaire were assessed in the autism group to explore factors associated with health-related risky behaviors. Multivariate regression analysis was conducted to explore the risk factors of health-related risky behaviors in the HFA group. RESULTS: The results showed that the total score of the Adolescents Health-related Risky Behavior Inventory and scores of "aggression and violence," "suicide and self-injury," "health compromising behavior" and "unprotected sex" subscales in the HFA group were significantly higher than those in the control group (Z range -4.197 to -2.213, P < 0.05). Among the associated factors, poor emotional experience (B = -0.268, P < 0.001), depression (B = -0.321, P < 0.001), low score of intelligence (B = -0.032, P = 0.042), low score of Theory of Mind test (B = -1.321, P = 0.003) and poor adaptation to school life (B = -0.152, P = 0.006) were risk factors. These risky behaviors may promote the occurrence of health-related risky behaviors in adolescents with HFA. CONCLUSION: This study showed that adolescents with HFA were more likely to be involved in health-related risky behaviors. Different health-related risky behaviors have different reasons.