Role of left posterior superior temporal gyrus in phonological processing for speech perception and production

TLDR

Speech perception and production models posit a phonological processing level, but it is debated whether input and output use separate systems, with the left posterior superior temporal gyrus emerging as a key overlapping region. The study reviews neuroscientific evidence that input and output phonological systems partially overlap. An event‑related fMRI experiment was conducted where participants listened to and covertly produced speech. Two left posterior superior temporal gyrus regions responded to both perception and production, indicating overlapping neural systems for phonological processing, with implications for verbal working memory models.

Abstract

Abstract Models of both speech perception and speech production typically postulate a processing level that involves some form of phonological processing. There is disagreement, however, on the question of whether there are separate phonological systems for speech input versus speech output. We review a range of neuroscientific data that indicate that input and output phonological systems partially overlap. An important anatomical site of overlap appears to be the left posterior superior temporal gyrus. We then present the results of a new event‐related functional magnetic resonance imaging (fMRI) experiment in which participants were asked to listen to and then (covertly) produce speech. In each participant, we found two regions in the left posterior superior temporal gyrus that responded both to the perception and production components of the task, suggesting that there is overlap in the neural systems that participate in phonological aspects of speech perception and speech production. The implications for neural models of verbal working memory are also discussed in connection with our findings.