Open AccessTemporospatial identification of language‐related cortical function by a combination of transcranial magnetic stimulation and magnetoencephalography
Author(s) -
Shinshi Misako,
Yanagisawa Takufumi,
Hirata Masayuki,
Goto Tetsu,
Sugata Hisato,
Araki Toshihiko,
Okamura Yumiko,
Hasegawa Yuka,
Ihara Aya S.,
Yorifuji Shiro
Publication year - 2015
Publication title -
brain and behavior
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 41
ISSN - 2162-3279
DOI - 10.1002/brb3.317
Subject(s) - magnetoencephalography , transcranial magnetic stimulation , neuroscience , stimulation , psychology , medicine , electroencephalography
Identification of language‐related cortical functions can be carried out noninvasively by transcranial magnetic stimulation ( TMS ) and magnetoencephalography ( MEG ), which allow for lesion‐based interrogation and global temporospatial investigation of cortices, respectively. Combining these two modalities can improve the accuracy of the identification, but the relationships between them remain unclear. We compared TMS and MEG responses during the same language task to elucidate their temporospatial relationships and used the results to develop a novel method to identify language‐related cortical functions. Methods Twelve healthy right‐handed volunteers performed a picture‐naming task during TMS and MEG . TMS was applied on the right or left inferior frontal gyrus ( IFG ) at five time points, and the reaction times ( RT s) for naming the pictures were measured. The temporospatial oscillatory changes measured by MEG during the same task were then compared with the TMS results. Results Transcranial magnetic stimulation of the left IFG significantly lengthened RT s at 300 and 375 msec after picture presentation, whereas TMS of the right IFG did not change RT s significantly. Interestingly, the stimulus time point at which RT s increased significantly for each individual was correlated with when the low gamma event‐related desynchronizations ( ERD s) peaked in the left IFG . Moreover, combining the results of TMS and MEG improved the detection rate for identifying the laterality of language function. Conclusions These results suggest that the low gamma ERD s measured by MEG strongly relate to the language function of picture naming in the left IFG . Finally, we propose a novel method to identify language‐related cortical functions by combining TMS and MEG .