We used model based functional MRI independent component analysis approach for the detection and characterization of the described networks functioning during simple motor task execution. Direct connection between the task execution and anticorrelated functional connectivity of sensory-motor and default mode networks was shown. We observed blood oxygenation level dependent signal (BOLD) frequency characteristics of the default mode network (DMN) together with the sensory motor network (SMN). The results demonstrate a reproducible specific configuration of BOLD low-frequency spectrum. Neural network BOLD spectral pro㌳le approach may be used for future analysis of its functioning and dynamics rules of brain regions connectivity. Regions of precuneus and posterior cingulate cortex were shown to deactivate just partially. Sensorimotor and default-mode networks were functionally connected in the anticorrelated manner with the prevailing frequencies of the BOLD signal oscillation f1 = 0.0153 ± 0.0051 Hz and f2 = 0.0204 ± 0.0051 Hz, where f – frequency of BOLD oscillation. At our study we have found out, that only some separate parts of pC and PCC were deactivated during the task execution. This possibly might support the hypothesis that non deactivated regions of precuneus (pC) and posterior cingulate cortex (PCC) remain active to regulate the transitions from the activated state to the deactivated and back while monitoring the external environment and commands. The last may support the hypothesis of the role of posterior cingulate cortex as a “hub” in default mode networks where non deactivated parts remain active for further control of others default mode networks region state switching.