Guest lecture: Stéphanie Riès

Frontal control mechanisms in language production

Stéphanie Riès is Assistant Professor in Speech, Language, and Hearing Sciences at the San Diego State University, USA, invited by Paragraphe

Adults fluidly utter 2 to 3 words per second selected from up to 100,000 words in the mental lexicon and only err once every 1000 words. Although seemingly easy, producing language is complex and depends on cognitive control processes that may be shared with non-linguistic cognitive functions. ln particular, cognitive control processes appear to be involved in helping us choose words as we speak. Despite the central importance of our capacity to produce language and the immense persona! and societal cost caused by its disruption, the spatio-temporal pattern of activation of the brain regions involved in word selection and the precise role of these brain regions are largely unknown. I will present results from scalp and intracranial electrophysiological studies and neuropsychological studies beginning to shed light on these issues. These results support the hypotheses that posterior inferior left temporal cortex engages in word retrieval as semantic concepts become available. ln parallel, medial and left prefrontal cortices tune in with left temporal activity on a trial-by-trial basis, supporting top-down control over interference resolution for word retrieval. Supporting these interpretations, computational modeling of neuropsychological data suggests the left Prefrontal Cortex plays a role in the adjustment of the decision threshold for word selection in language production in situations of interference caused by semantically-related neighbors. The implication of these findings for developing the understanding of acquired (i.e., stroke-induced aphasia) and developmental language disorders (i.e., dyslexia) and the possible compensatory, mechanisms involved will be discussed.

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Date: Thursday, May 23, 2019 from 12:30 to 14:00

Venue: Maison internationale de la recherche, Neuville-sur-Oise.