DYNAMICS OF BRAIN ACTIVATION DURING PICTURE NAMING

THE cerebral representation of language, deduced from observing patients with brain lesions and from stimulations and recordings performed during brain surgery1,2, has been further clarified by recent positron emission tomography3 and functional magnetic resonance imaging measurements4. We now expand this static view into the dynamics of cortical activation using the accurate spatiotemporal resolution of whole-head magnetoencephalography5. During picture naming, the conversion from visual to symbolic representation progressed bilaterally from the occipital visual cortex towards temporal and frontal lobes. Overt naming elicited the most widespread cortical activation. Some language-related sites also reacted, though more weakly or after a longer delay, during covert naming and even passive viewing.