The dynamic processes for word and picture encoding in the human brain as revealed by magnetoencephalography

Subjects were asked to memorize either the size or the meaning of the first stimulus (encoding) of a stimulus pair, and to match it to the second stimulus. Words and pictures were used as the stimuli in separate tests. Two components named 1M and 2M in both hemispheres for word or picture stimuli could be detected by magnetoencephalography (MEG). The dipole location of 1M in bilateral hemispheres for words is different from that for pictures, but that of 2M is not. It is considered that picture and word are processed in different systems at the initial stage, mainly in the lateral temporal cortex for words and in the parietal cortex for pictures, whereas they are processed in a common semantic system at the late stage.