Atypical temporal lobe language representation: MEG and intraoperative stimulation mapping correlation

FUNCTIONAL brain imaging techniques hold many promises as the methods of ch oice for identifying areas involved in the execution of language functions. The success of any of these techniques in fulfilling this goal depends upo n their ability to produce maps of activated areas that overlap with those obtained through standard invasive procedures such as electrocortical stimu lation. This need is particularly acute in cases where active areas are fou nd outside of traditionally defined language areas. In the present report w e present two patients who underwent mapping of receptive language are as p reoperatively through magnetoencephalography (MEG) and intraoperatively thr ough electrocortical stimulation. Language areas identified by both methods were located in temporoparietal regions as well as in less traditional reg ions (anterior portion of the superior temporal gyrus and basal temporal co rtex). Importantly there was a perfect overlap between the two sets of maps . This clearly demonstrates the validity of MEG-derived maps for identifyin g cortical areas critically involved in receptive language functions. (C) 1 999 Lippincott Williams & Wilkins.