Error in the superior temporal gyrus? A systematic review and ALE meta-analysis of speech production studies

Evidence for perceptual processing in models of speech production is often drawn from investigations in which the sound of a talker’s voice is altered in real time to induce ‘errors’. Methods of acoustic manipulation vary, but are assumed to engage the same neural network and psychological processes. This article aims to review fMRI and PET studies of altered auditory feedback, and assess the strength of the evidence these studies provide for a speech error correction mechanism. Studies included were functional neuroimaging studies of speech production in neurotypical adult humans, using natural speech errors or one of three predefined speech manipulation techniques (frequency altered feedback, delayed auditory feedback and masked auditory feedback). 17 studies met the criteria. Eight of 17 studies did not include an appropriate listening control condition and nine did not collect data showing behavioural compensation. 16 studies reported co-ordinates of brain areas that responded preferentially to manipulated over unmanipulated speech production; these were analysed using the GingerALE toolbox. These foci clustered in bilateral superior temporal gyri (STG), but did not overlap with the cortical fields typically linked to error correction, which lie posterior to these foci. We conclude that neuroimaging evidence is insufficient to confirm accounts of error monitoring