This past year we completed several clinical and brain imaging investigations of adolescents with Autism Spectrum Disorders (ASD). Our clinical studies focused on a number of ASD-related behavioral characteristics and issues. In one study we showed that although high-functioning adolescents with ASD tended to have more intense and idiosyncratic interests and hobbies than age and IQ matched control subjects, their interests were not more restricted in number, as has been commonly thought. In fact, it was the intensity with which they pursued these interests and hobbies, rather than their total number, that was most strongly related to other ASD symptoms. In a separate study we found that the speed at which subjects performed relatively simple cognitive tasks was strongly related to ASD symptoms including difficulties with social communication. This finding suggests that speed of performance may be a useful predictor of functional outcome in ASD. Finally, contrary to recent claims that symptoms of depression and anxiety are associated with higher IQ and fewer ASD symptoms, we observed an increased risk for depression/anxiety symptoms in our high-functioning children and adolescents with ASD, regardless of IQ or ASD symptoms. Our structural brain imaging studies have continued to document abnormally thin cortex, as well as increased cortical gyrification, in ASD subjects relative to matched control subjects. These findings are consistent with an ever-growing literature on cortical atypicalities in ASD. We have also continued to document the functional consequences of these atypicalities using functional MRI. In a series of studies, we found that the neural circuitry associated with perceiving and understanding social interactions showed a lack of category-specificity in the ASD subjects. Specifically, brain regions that typically respond to complex motion, such as when viewing social, relative to mechanical interactions, responded equally strong to both types of interactions in ASD subjects. One interpretation of this finding is that ASD may be characterized by deficient neural connectivity within brain regions comprising the social processing network. Our studies of functional brain connectivity supported this possibility. In collaboration with the NIMH Scientific and Statistical Computing Core, we developed an unbiased, data-driven, procedure for identifying brain regions showing abnormal patterns of functional connectivity using resting-state fMRI data. During a resting-state scan, subjects simply lie quietly in the scanner, not performing any specific task. Under these conditions, spatially distant regions of the brain can show similar patterns of slowly fluctuating neural activity. The strength of similarity, or correlation, between the fluctuations in different brain regions can be used as a measure of the strength of the connections between them. Our study identified several regions of the ASD brain that showed abnormally weak connections with other brain regions. These regions included the medial portions of prefrontal cortex, the amygdala, and anterior and posterior regions of the temporal lobes, all of which have been strongly associated with social cognition. Importantly, the strength of the connections we observed was related to social deficits of our ASD subjects as determined by behavioral ratings provided by their parents - the greater the social difficulty the weaker the functional connectivity. Resting-state fMRI data have proven to be particularly useful for comparing clinical patient groups because they are easy to obtain and are not subject to group differences in performance that can confound the interpretation of task-based neuroimaging data. However, the analysis of these data is fraught with a problems and pitfalls that have not been fully appreciated or explored. To help remedy this situation, we have published several papers that describe these difficulties in detail and offer potential solutions.

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Project End
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Budget End
Support Year
5
Fiscal Year
2013
Total Cost
$997,922
Indirect Cost
Name
U.S. National Institute of Mental Health
Department
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Power, Jonathan D; Plitt, Mark; Kundu, Prantik et al. (2017) Temporal interpolation alters motion in fMRI scans: Magnitudes and consequences for artifact detection. PLoS One 12:e0182939
Ramot, Michal; Kimmich, Sara; Gonzalez-Castillo, Javier et al. (2017) Direct modulation of aberrant brain network connectivity through real-time NeuroFeedback. Elife 6:
Power, Jonathan D (2017) A simple but useful way to assess fMRI scan qualities. Neuroimage 154:150-158
Power, Jonathan D; Plitt, Mark; Laumann, Timothy O et al. (2017) Sources and implications of whole-brain fMRI signals in humans. Neuroimage 146:609-625
Wallace, Gregory L; Dudley, Katerina; Anthony, Laura et al. (2017) Divergence of Age-Related Differences in Social-Communication: Improvements for Typically Developing Youth but Declines for Youth with Autism Spectrum Disorder. J Autism Dev Disord 47:472-479
White, Emily I; Wallace, Gregory L; Bascom, Julia et al. (2017) Sex differences in parent-reported executive functioning and adaptive behavior in children and young adults with autism spectrum disorder. Autism Res 10:1653-1662
Kraper, Catherine K; Kenworthy, Lauren; Popal, Haroon et al. (2017) The Gap Between Adaptive Behavior and Intelligence in Autism Persists into Young Adulthood and is Linked to Psychiatric Co-morbidities. J Autism Dev Disord 47:3007-3017
Wallace, Gregory L; Kenworthy, Lauren; Pugliese, Cara E et al. (2016) Real-World Executive Functions in Adults with Autism Spectrum Disorder: Profiles of Impairment and Associations with Adaptive Functioning and Co-morbid Anxiety and Depression. J Autism Dev Disord 46:1071-83
Pugliese, Cara E; Anthony, Laura Gutermuth; Strang, John F et al. (2016) Longitudinal Examination of Adaptive Behavior in Autism Spectrum Disorders: Influence of Executive Function. J Autism Dev Disord 46:467-77
Berman, Rebecca A; Gotts, Stephen J; McAdams, Harrison M et al. (2016) Disrupted sensorimotor and social-cognitive networks underlie symptoms in childhood-onset schizophrenia. Brain 139:276-91

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