Abnormal spatial and temporal concordance between local spontaneous intrinsic brain activity measures across three major psychiatric disorders.

Fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo) are frequently used to assess local spontaneous brain activity and identify functional abnormalities in schizophrenia (SZ), bipolar disorder (BD), and attention deficit/hyperactivity disorder (ADHD), yet their spatial and temporal coupling alterations in these psychiatric disorders remain unclear. Here, resting-state functional MRI data were collected from a sample of patients with SZ, BD, and ADHD as well as healthy controls. Kendall's W was utilized to calculate volume-wise and voxel-wise concordance between fALFF and ReHo, followed by performance of group comparisons. Results showed that SZ and BD had decreased volume-wise concordance relative to ADHD and controls. Compared with controls, SZ showed decreased voxel-wise concordance in broadly distributed gray matter areas, and BD demonstrated localized voxel-wise concordance decrease in the anterior cingulate cortex. Additionally, direct comparisons between disorders revealed that SZ exhibited decreased voxel-wise concordance in the prefrontal and occipital cortex relative to BD, and widespread voxel-wise concordance decrease in the prefrontal, occipital and temporal regions relative to ADHD. BD showed circumscribed voxel-wise concordance decrease in the supramarginal gyrus relative to ADHD. These findings suggest different patterns of spatial and temporal decoupling between local intrinsic brain activity measures across these major psychiatric disorders.