Sleep is a reversible state of consciousness associated with reduction of awareness, response to external stimuli, and appearance of behavioral and physiological changes. The perception of sleep, by definition, is measured by subjective report. Previous study has shown that perception of sleep is associated of loss of thinking process, as well as decreased experience of sensation and perception (Yang, Han, Yang, Su, & Lane, 2010). However, the neurophysiological mechanism underlying sleep perception remains uncertain. The aim of this study is to use EEG and fMRI to compare the difference in brain activities before awakenings with and without perception of sleep.