Fractal analysis of spontaneous fluctuations of the BOLD signal in rat brain

► We assessed fractality in BOLD signal fluctuations by the dichotomous 1/fβ model. ► Most signals were fGn, some fBm, the latter interferent with connectivity analysis. ► The difference between cortical and subcortical βs diminished post mortem. ► Near-zero post mortem β is due to deoxyhemoglobin impacting tissue water diffusion. ► Level of anesthesia decreased β in the cortex, only.