Objectives: To assess the differences in the distribution of the Hurst exponent in spontaneous BOLD signal fluctuations from fMRI brain imaging in adults with ASC and matched controls.
Methods: 31 adult, right-handed males (18-45 years old) with a clinical and ADI-R confirmed diagnosis of ASC, and 33 age-, sex-, handedness- and IQ-matched neurotypical adults were scanned in a 3T MRI scanner by echo planar imaging in an eye-closed, awake, non-task resting state. Following preprocessing of the acquired images to correct for motion, maps of H were generated at each intra-cerebral voxel for each participant. These were then co-registered into the standard anatomical space of the Montreal Neurological Institute by affine transform and cross-section statistical analysis at the cluster level performed using permutation inference (CamBA v2.2.0 http://www-bmu.psychiatry.cam.ac.uk/software/).
Results: Statistical significance was set such one false positive cluster was expected under the null-hypothesis (equivalent p=0.003). At this level widespread increases in H were observed in participants with ASC relative to controls, particularly in the limbic systems and the anterior cingulate.
Conclusions: These data provide preliminary evidence that H may be substantively different in resting neural oscillations in ASC compared with matched controls. The regions identified have previously been implicated with ASC using other imaging techniques and it seems therefore plausible that changes in the persistence of fMRI time-series reflect changes in the underlying neural systems associated with the condition.