Supplementary Motor Area Activation in Disfluency Perception: An fMRI Study of Listener Neural Responses to Spontaneously Produced Unfilled and Filled Pauses

Spontaneously produced Unfilled Pauses (UPs) and Filled Pauses (FPs) were played to subjects in an fMRI experiment. For both stimuli increased activity was observed in the Primary Auditory Cortex (PAC). However, FPs, but not UPs, elicited modulation in the Supplementary Motor Area (SMA), Brodmann Area 6. Our results provide neurocognitive confirmation of the alleged difference between FPs and other kinds of speech disfluency and could also provide a partial explanation for the previously reported beneficial effect of FPs on reaction times in speech perception. Our results also have potential implications for two of the suggested functions of FPs: the “floor-holding” and the “help-me-out” hypotheses.