Mismatch Negativity (MMN) reflects a neural mismatch between an incoming stimuli and the transient representation of stimuli in short-term memory. MMN mechanism forms the basis of unattended change detection, which may lead to the switching of involuntary attention. We used high resolution EEG and LORETA images to investigate the changes of MMN sources over time. Individual structural MRI was used for realistic head modeling and each electrode position in 3-D space was digitized. The right frontal area was activated later than the temporo-parietal generator. The temporo-parieto-frontal network is responsible for template updating and an involuntary attention switch to changes in the auditory environment.