Functional Connectivity in Autism Spectrum Disorders: Challenges and Perspectives

There is broad agreement that in autism spectrum disorders (ASDs), the connectivity within and across numerous functional brain networks is affected. Resting-state functional connectivity MRI (rs-fcMRI) has become a method of choice in connectivity studies of ASDs, yet a clear picture of exact patterns of atypical network organization has yet to emerge. Inconsistent findings and lack of uniquely specific biomarkers can, in part, be attributed to etiological heterogeneity. Cohort effects may be mitigated in large multisite samples, but statistically significant findings with small effect size in highly powered studies require careful interpretation. Differences in scanning protocols and diverse data processing and analysis procedures create additional methodological challenges in functional connectivity research of ASDs. Standardized data collection and rich phenotyping in large samples will be critical to overcome these challenges. However, there are also concerns about the use of “resting states” for fMRI data acquisition, and better controlled natural stimulation may be a preferable alternative.