International Meeting for Autism Research (May 7 - 9, 2009): Default Mode Network in Patients with High Functioning Autism Spectrum Disorders during Resting State fMRI

Thursday, May 7, 2009: 3:10 PM

Northwest Hall Room 2 (Chicago Hilton)

L. Miller , Olin Neuropsychaitry Research Center, Institute of Living, Hartford Hospital, Hartford, CT

K. Jagannathan , Olin Neuropsychiatry Research Center,, Institute of Living, Hartford Hospital, Hartford, CT

J. O'Boyle , Trinity College Dublin, Hartford, CT

R. T. Schultz , Pediatrics, Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA

M. C. Stevens , Olin Neuropsychiatry Research Center, Institute of Living, Hartford Hospital / Yale University, Hartford, CT

R. Sahl , Psychiatry, Institute of Living, Hartford Hospital, Hartford, CT

G. Pearlson , Olin Neuropsychiatry Research Center, Institute of Living, Hartford Hospital / Yale University, Hartford, CT

M. Assaf , Olin Neuropsychiatry Research Center, Institute of Living, Hartford Hospital / Yale University, Hartford, CT

Background: Autism Spectrum Disorders (ASD) are characterized by deficits in social and communication processes. It has been suggested that brain-wide reduced functional connectivity, including in the default mode network (DMN), might underlie these deficits. Past research has found that activation of the DMN, a brain network that is activated during passive task states, is related to social and emotional processing and that its connectivity might be impaired in ASD.

Objectives: 1) To compare DMN strength of functional connectivity of ASD patients to matched Healthy Controls (HC) during fMRI resting state scan using Independent Component Analysis (ICA); and 2) to evaluate the correlation between DMN strength of functional connectivity and severity of patients’ symptoms as measured by the Autism Diagnostic Observation Schedule (ADOS).

Methods: Resting state fMRI data with no cognitive task were collected from fifteen high functioning ASD patients and fifteen HC matched on age, gender and race. was used to identify the DMN. Group differences were examined using random effect two sample t-tests and multiple regression analysis was used to measure the correlation between DMN connectivity strength and ADOS scores. All analyses were corrected for age and IQ.

Results: The results indicated that within the DMN, patients showed significantly weaker strength of regional activity in the posterior cingulate gyrus and the precuneus. Correlation analysis showed that as patients had more severe symptoms as measured by the ADOS, they had less regional connectivity of the precuneus, a key region in DMN.

Conclusions: Our data suggests that ASD patients show decreased connectivity in the default mode compared to HC and that this abnormal connection correlates with their symptom severity. Due to the simplicity and the short time span of resting state scans, this method can be applied to lower functioning and younger individuals and possibly used as a biomarker for Autism in future genetic and treatment studies. This work was supported by Autism Speaks and Hartford Hospital .

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