[The science of the mental present: implications of temporal illusions]

Mental time consists of the mental present, past, and future. In this review, we aimed to elucidate how the brain constructs the mental present, by assessing several temporal illusions that occur within a time frame smaller than one second. We first reviewed the color phi phenomenon and the cutaneous rabbit phenomenon, followed by the flash-lag effect, and finally, reversal of the subjective temporal order due to arm-crossing and saccadic eye movements. After examining the hypotheses that explain each illusion, we proposed that the mental present is constructed in a postdictive manner by combining different aspects of information, such as motion and spatial positions, which are represented over multiple areas in the cerebral cortex. On the basis of the classic time quantum theory and recent findings in neurophysiology and psychology, we further suggest that the mental present is constructed by combining information from one to several periods of -100 ms, each consisting a period of the alpha rhythm in the brain.