Reduced amplitude of low frequency fluctuation in the sensorimotor cortex in early psychosis: association with motor dexterity and hyperconnectivity

Previous studies have demonstrated widespread regional abnormalities in blood oxygen level-dependent (BOLD) amplitude of low frequency fluctuation (ALFF) in psychotic disorders. How regional ALFF is related to functional connectivity and behavior in psychotic illness, however, is poorly understood. Here we examined voxelwise ALFF across the brains of subjects with early psychosis (EP) vs. healthy controls (HCs) as well as its relationships to functional connectivity and task performance. Resting state fMRI data from 55 HCs and 109 participants with EP from the Human Connectome Project-Early Psychosis were analyzed. Our analytic strategy was to examine ALFF across the whole brain to determine what regions showed significant differences in the psychosis group and then determine how those regional abnormalities in ALFF were related to connectivity patterns with other brain areas. We then examined correlations between these measures and performance on task-relevant to the observed circuitry. Significantly lower ALFF was observed in the sensorimotor cortex in participants with EP vs. HC. Decreased sensorimotor ALFF in EP, furthermore, was associated with poor motor dexterity and cognitive function. Finally, in participants with EP, ALFF showed increased connectivity with the cerebellum, anterior cingulate, and insula. Our results suggest that spontaneous low-frequency blood oxygen level-dependent fluctuation amplitude is significantly lower in sensorimotor cortex in EP, and that this change is associated with poor motor skills and cognition. Hyperconnectivity within the observed circuits in participants with EP may indicate more widespread pathology with areas that show abnormally low levels of baseline BOLD fluctuation.