Transcranial Magnetic Stimulation in Speech and Language Research

Transcranial magnetic stimulation (TMS), as we use it today, was developed in the 1980s, and already in the 1990s, it was clear it would became an essential tool to study human brain functions. The present chapter focuses on the technical challenges that are specific to the use of TMS in speech and language research. A section is devoted to the co-registration of TMS and electroencephalography (EEG), highlighting the great potential as well and the challenges inherent in the integration of these two techniques. The chapter briefly revises the extensive literature using TMS in speech and language research by separating the different available protocols. In particular, trains of TMS pulses can transiently interfere with the activity of a relatively specific cortical target. This approach, often named “virtual lesion approach,” has been used to investigate the role of posterior and anterior language brain areas in receptive and production tasks, respectively. Otherwise, single or paired-pulse protocols measure neurophysiological indexes of intracortical or corticomotor excitability. In this respect, TMS research has shown a specific motor recruitment during speech perception tasks, suggesting a tight functional relationship between production and perception mechanisms. In conclusion, we provide key methodological and technical suggestions on how to best approach the design of TMS studies, based on this relatively mature field of research.