FIG 1. Spontaneous MEG data are waveforms showing how magnetic flux changes with time. Data regarding the trauma patients often show generalized slowing of the background activity and focal slow waves. Ten seconds of data are shown from several channels. Two examples of slow waves are marked by the green and red lines. One way to express the data is as a power spectrum, shown on the right. Most slow waves have complicated magnetic field patterns, as shown by the leftmost iso-field contour map. Some slow waves have very dipolar patterns, and the source can be localized and plotted on spatially aligned MR images. The red dot shows the location of the indicated slow wave, with black dots showing slow-wave sources from other points in time