Combining Functional Neuroimaging with Off-line Brain Stimulation: Modulation of Task-related Activity in Language Areas

摘要

Repetitive TMS (rTMS) provides a noninvasive tool for modulatingnneural activity in the human brain. In healthy participants,nrTMS applied over the language-related areas in the left hemisphere,nincluding the left posterior temporal area of Wernicken(LTMP) and inferior frontal area of Broca, have been shown tonaffect performance on word recognition tasks. To investigatenthe neural substrate of these behavioral effects, off-line rTMSnwas combined with fMRI acquired during the performance of anword recognition task. Twenty right-handed healthy men underwentnfMRI scans before and after a session of 10-Hz rTMS appliednoutside the magnetic resonance scanner. Functional magneticnresonance images were acquired during the performance of anword recognition task that used English or foreign-languagenwords. rTMS was applied over the LTMP in one group of 10 participantsn(LTMP group), whereas the homologue region in thenright hemisphere was stimulated in another group of 10 participantsn(RTMP group). Changes in task-related fMRI responsen(English minus foreign languages) and task performances (responsentime and accuracy) were measured in both groups andncompared between pre-rTMS and post-rTMS. Our results showednthat rTMS increased task-related fMRI response in the homologuenareas contralateral to the stimulated sites. We also foundnan effect of rTMS on response time for the LTMP group only.nThese findings provide insights into changes in neural activitynin cortical regions connected to the stimulated site and are consistentnwith a hypothesis raised in a previous review about thenrole of the homologue areas in the contralateral hemisphere fornpreserving behavior after neural interference