Performance of a task involves the engagement of various brain areas, as evidenced by the effects of lesions of particular brain areas and the results of functional neuroimaging and neurophysiological studies. Here, we tested the hypothesis that overall task performance would depend on the level of ongoing, resting-state change in synaptic activity of participating areas, such that the degree of success of the outcome would be higher, the higher the resting-state activation. For that purpose, we used 248-sensor magnetoencephalography (MEG) in healthy people to obtain estimates of resting-state synaptic activity in various areas and then correlated those estimates to the average performance score in three visuospatial tasks assessed outside the MEG session using the Montreal Cognitive Assessment (MoCA), namely, the trails, cube, and clock drawing (TCCD) tasks. We found that the average success score in these tasks covaried positively with the level of resting-state neural activity of three broad area clusters, namely,