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Stéphanie Riès. Frontal control mechanisms in language production


What: Frontal control mechanisms in language production

Where:  Zoom room 2

Who: Stéphanie Riès, PhD, Assisstant Professor, Speech Language; Director, Laboratory for the Brain Dynamics of Language. San Diego State University, San Diego, US.

When:  Thursday,  October 7th at 3:00 PM.

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 personal 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 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 that 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. In addition, the disruption of input from the medial prefrontal cortex can severely impact semantic interference resolution. The implication of these findings for developing the understanding of acquired language disorders and bilingual language control will be discussed.