Mertens, B. , Kemp, N. & Garry, M.
School of Psychology. University of Tasmania. Hobart, Australia.
Previous research suggests processing of motor-related language involves motor cortex structures. This study aimed to investigate how the influence of the motor cortex during language processing may be impacted by creating a motor association to words that previously had no motor association. Reaction time (RT) and electromyographic data were recorded from 15 participants in response to hand-action and non-action verbs across two sessions. Between sessions participants practised simple sign language. Real or sham transcranial magnetic stimulation (TMS) was applied over the motor cortex during word processing on some trials. It was expected that real TMS would interfere with motor cortex function resulting in a delay when processing words with high motor association (hand-action words with signs), whereas there would be minimal impact on RT when processing words with low/no motor association (non-action words with no signs). The hypothesised effect of TMS on word type was not supported, however, it was observed that in the first session, regardless of word type, RT was delayed when real, but not sham TMS was delivered. The role of TMS pulse timing and intensity are being investigated as a possible explanation for the observed results.