Is word-level lexical stress sensitivity affected by downregulation to the left superior temporal gyrus using TMS?

Abstract

This paper reports two experiments using Transcranial Magnetic Stimulation (TMS) to investigate whether word-level lexical stress involves the left superior temporal gyrus (STG) using a grammar classification task designed to elicit a typicality effect. Experiment 1 used text presented stimuli and, although was not able to elicit a typicality effect, found response times were significantly slower in the no TMS condition compared to when the, control, right PAR region was downregulated. In Experiment 2, speech was presented instead of text and accuracy and response times were similar across all three conditions. A lexical decision control task found evidence, from response time analysis, that the left STG and the right PAR were involved in word and nonword judgments. The discussion explores the findings relative to lexical stress and the role of cortical regions in word and response processing. • Participants made grammar classifications for two-syllable words. • The words presented had either typical or atypical prosody. • The study used no TMS and inhibitory TMS to the left STG and the right PAR. Response times were significantly slower in the no TMS condition compared to the right PAR condition. • A lexical decision control task found evidence that the left STG and the right PAR were involved in word and nonword judgments.