DYNAMICS OF BRAIN ACTIVATION DURING PICTURE NAMING

THE cerebral representation of language, deduced from observing patien ts with brain lesions and from stimulations and recordings performed d uring brain surgery1,2, has been further clarified by recent positron emission tomography3 and functional magnetic resonance imaging measure ments4. We now expand this static view into the dynamics of cortical a ctivation using the accurate spatiotemporal resolution of whole-head m agnetoencephalography5. During picture naming, the conversion from vis ual to symbolic representation progressed bilaterally from the occipit al visual cortex towards temporal and frontal lobes. Overt naming elic ited the most widespread cortical activation. Some language-related si tes also reacted, though more weakly or after a longer delay, during c overt naming and even passive viewing.