We reconstruct the entire experimentally observed spatio-temporal signal of a human magnetoencephalogram (MEG) observed in a sensori-motor-coordination experiment by Kelso et al. In this experiment, when an acoustic stimulus frequency is changed systematically, a spontaneous transition in coordination occurs at a critical frequency in both the motor behavior and brain signals. Here we present a stepwise approach for the reconstruction of the spatio-temporal signal: First, we identify the order parameters and recall a theoretical model by the present authors and Kelso which reproduces the temporal dynamics of the order parameters. Second, we use the variational method by Uhl et al. in order to determine the spatial modes of the order parameters. Third, we present a variational method for the reconstruction of the remaining spatio-temporal signal and determine the spatial modes and temporal dynamics of the enslaved variables and possible order parameter modifications. The obtained set of spatial modes proves to be a fixed spatial base system of the observed temporal dynamics in the brain.,