The Dynamic Measurements of Regional Brain Activity for Resting-State fMRI: d-ALFF, d-fALFF and d-ReHo

The human brain is always in the process of constantly changing. Given that the conventional measurements of regional brain activity are less sensitive to changes over time, three dynamic measurements were proposed to capture the temporal variability of regional brain activity. In this study, dynamic amplitude of low frequency fluctuation (d-ALFF), dynamic fractional amplitude of low frequency fluctuation (d-fALFF) and dynamic regional homogeneity (d-ReHo) were obtained from resting-state functional magnetic resonance imaging (rs-fMRI) of both 238 ADHD and 239 typical developing (TD) subjects. Then, they were applied to detecting the regional activity differences between ADHD and TD group. Compared with the conventional measurements (ALFF, fALFF and ReHo), the dynamic measurements were more sensitive in exploring the differences of regional brain activity between ADHD and TD group. The three new measurements not only enrich the diversity of methods for investigating the dynamic variation of regional brain activity, but also emphasize the significance of detecting the temporal variability of regional brain activity.