Poster F110, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
fMRI-guided theta burst stimulation to the superior temporal cortex impairs sentence processing.
Marina Bedny1, Judy Kim1, Gabriela Cantarero2,3, Pablo Celnik2; 1Johns Hopkins University, 2Johns Hopkins School of Medicine, 3Walter Reed Army Institute of Research
Sentence processing recruits regions in inferior frontal and lateral temporal cortices (e.g., Fedorenko et al., 2011). Here, we asked whether off-line, continuous theta burst stimulation (cTBS) to these areas disrupts sentence processing. Twelve participants underwent an fMRI scan while listening to sentences and answering true/false questions. Each sentences contained two actors, and questions asked about who did what to whom. In a control condition, participants performed a working memory task with lists of nonwords. Stimulation was delivered to the left inferior frontal cortex (IFC), left superior temporal cortex (STC), or vertex. Stimulation sites were identified based on individual-subject fMRI activation during sentence processing (sentences>nonwords). We measured sentence comprehension and non-word memory performance immediately before and after cTBS. In the baseline vertex condition, performance for sentences improved following stimulation (post-pre=9%). In contrast, performance for sentences did not improve after STC stimulation (post-pre=1%) (vertex vs. STC t(11)=2.59, p<.05), suggesting that STC stimulation extinguished within-session improvement. Effects of IFC stimulation on performance did not differ from the effects of vertex stimulation. Further, the effects of cTBS to IFC, STC, and vertex on nonwords performance did not differ. Our results suggest that cTBC to STC selectively impairs sentence processing, and that cTBS may have different effects on IFC and STC.
Topic Area: METHODS: Other