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Neural correlates of natural speech errors during continuous picture naming

Poster A72 in Poster Session A, Thursday, October 6, 10:15 am - 12:00 pm EDT, Millennium Hall
Also presenting in Poster Slam A, Thursday, October 6, 10:00 - 10:15 am EDT, Regency Ballroom

Angelique Volfart1, Katie McMahon1,2, David Howard3, Greig I. de Zubicaray1; 1Queensland University of Technology, 2Herston Imaging Research Facility, 3Newcastle University

The majority of our knowledge about the neuroanatomy of speech errors comes from lesion-symptom mapping (LSM) studies in people with aphasia (PWA) and laboratory paradigms designed to elicit primarily phonological errors in healthy adults, with comparatively little evidence from naturalistic speech production. In this study, we analysed perfusion fMRI data from 24 healthy participants during continuous picture naming and classified their responses into correct and speech error types (e.g., semantic, phonological, omission errors, etc.). Total speech errors engaged a wide set of left-lateralized frontal, parietal and temporal regions that were almost identical to those involved during the production of correct responses. We observed significant perfusion signal decreases in the left posterior middle temporal gyrus (pMTG) and angular gyrus for semantic paraphasias compared to correct trials matched on various psycholinguistic variables. In addition, the left dorsal caudate nucleus showed a significant perfusion signal decrease for omission (i.e., anomic) errors compared with matched correct trials. We did not observe any significant perfusion signal changes in brain regions proposed to be associated with monitoring mechanisms during speech production (e.g., anterior cingulate cortex, superior temporal gyrus). Overall, our findings provide evidence for distinct neural correlates of semantic and omission error types, and indicate that mechanisms responsible for speech errors in healthy participants might vary with those reported for PWA.

Topic Areas: Language Production, Control, Selection, and Executive Processes