Presentation
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Alpha and beta oscillations differentially support linguistic demands in a rule-switching task
Poster A85 in Poster Session A, Tuesday, October 24, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Ioanna Zioga1,2, Ying Joey Zhou1,3, Hugo Weissbart1, Ashley G. Lewis1,2, Andrea E. Martin1,2, Saskia Haegens1,4,5; 1Donders Institute for Brain, Cognition and Behaviour, Center for Cognitive Neuroimaging, Radboud University, Nijmegen, the Netherlands, 2Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands, 3Oxford Centre for Human Brain Activity, Oxford, UK, 4Columbia University, New York, USA, 5New York State Psychiatric Institute, New York, USA
Human and non-human primate research has investigated the role of brain oscillations in basic cognitive functions. In particular, alpha oscillations are related to facilitated processing through the inhibition of task-irrelevant networks, while beta oscillations seem to carry content information about task rules. However, little is known with regard to the generalization of fundamental operations to more complex processes. Here, we constructed a novel rule-switching paradigm incorporating functions from working memory and language comprehension to word production, in order to study the role of alpha and beta dynamics during high-level processing. Specifically, Dutch native speakers were required to come up with an alternative exemplar from the same category or a feature of a given target word (e.g., for the word tuna an exemplar from the same category -seafood- would be shrimp, and a feature would be pink) embedded in spoken sentences. In each trial, a cue indicated the task rule (exemplar or feature) either before listening to the sentence (pre-cue) or after the sentence and a delay period (retro-cue). Participants were prompted to verbalize their answer at the end of the trial. Magnetoencephalography (MEG) was recorded throughout. As expected, reaction times of word production were longer for retro-cue compared to pre-cue, due to higher cognitive load. Reaction times were also longer for features compared to exemplars. Interestingly, participants generated more diverse responses for features compared to exemplars, suggestive of increased association strength for exemplars. Surprisingly, there was a correlation between responses’ word frequency and reaction times, potentially due to contextual constraint effects of the sentences. On the neural level, alpha power during a delay period in the working memory task was lower for retro-cue compared to pre-cue in left hemispheric language-related regions. Critically, the power at each individual’s peak alpha frequency negatively correlated with reaction times, providing evidence for the role of alpha in facilitating task performance by regulating inhibition in regions linked to lexical retrieval. Furthermore, the spatiotemporal pattern of beta activity was dissociated between exemplars vs. features in right temporo-parietal regions, but only when participants were aware of the task rule, which is in line with the proposed role of beta oscillations in the encoding of distinct categories and recruitment of their respective neural networks. Overall, our study provides evidence for the generalizability of the role of alpha and beta oscillations from perceptual to complex linguistic processes, and offers a novel task to investigate links between rule-switching, working memory, and word production.
Topic Areas: Speech Perception,