A Contribution to the Role of the Putamen-Claustrum-Insular Region in Speech Motor Control Processes

The study aims to contribute to the understanding of the role of the putamen-claustrum-insular region (region of interest, ROI) in speech motor control processes, considering functional magnetic resonance imaging (fMRI) and acoustic analysis. Forty-three neurotypical participants performed visually presented motor planning and execution tasks (two highly frequent non-word CV-syllable sequences), which differ in gestural complexity. First, it can be shown that the ROI generally plays a role during motor planning and motor execution. Second, comparing blood oxygen level-dependent (BOLD) responses across the complexity conditions revealed that syllables with greater gestural complexity elicited increased activation in the bilateral ROI. This region may help to coordinate articulatory movements in articulatory subsystems. The intricacy of these glottal and supraglottal articulatory movements defines the gestural complexity of the respective speech sound. Finally, our results suggest that these differences in BOLD response in the ROI reflect the differential contribution of articulatory mechanisms that are required to produce phonologically distinct speech sounds.