To clarify the mechanism of adaptation to stress in the brain, we performed neuroimaging studies by functional magnetic resonance imaging and magnetoencephalography. First, to investigate which areas of the brain play an important role in the perception of stressful events, we performed fMRI for recognition of unpleasant words concerning interpersonal relationships. Secondly, we evaluated the effect of various stresses on the sensory gating system by MEG to show whether stress could affect the brain mechanism. Finally, we studied the neural activity associated with the expectancy of emotional stimuli using fMRI and MEG, because of the importance of expectancy in adaptation to stress. Our results suggested that stressful events might be recognized in the same brain regions, that acute stress might affect one brain mechanism, and that expectancy might suppress incoming stressful stimuli.