Findings from neuroimaging studies show low replication rates, but the origin of the problem is not clear. The current project explored the extent of the time-of-day dependent metabolic variation to the replication crisis. Using data from the human connectome project (HCP) release S1200, cross-spectral density dynamic causal modelling was used to analyse time-dependent effects on the hemodynamic response and effective connectivity parameters in the spontaneous fluctuations (>0.1Hz) of the blood oxygenation level dependent (BOLD) signal. Hierarchical group-parametric empirical Bayes found no support for time-of-day variations in effective connectivity, whereas the hemodynamic parameters exhibited a significant time-of-day dependent effect. It is concluded that these findings urge the need to account for the time of day in data acquisition of future MRI studies. Moreover, data from the human connectome project suggest that the relationship between functional and dynamic connectivity and the BOLD signal might not be direct.
bioRxiv Subject Collection: Neuroscience