What: Prediction in Language Processing: ERP Components and Oscillatory Coherence in Aging
Where: BCBL auditorium
Who: Spyridoula Cheimariou, PhD, Assistant Professor. Communicative Disorders, The University of Alabama Speech and Hearing Center, Alabama, USA
When: 12:30 PM
The N400 ERP component has been extensively studied in terms of predictiveness and congruency in younger adults, but the underlying mechanisms are still unclear. Also, although, there is a growing body of research on the neural dynamics of predictive processing in younger adults, older adults’ oscillatory responses have not been investigated yet. A number of studies have indicated the role of synchronization at different frequencies as a means for exploring and distinguishing pre-activation and integration during language processing. Here, we report findings from a picture-word matching task in which we crossed predictiveness and congruency. We conducted a) a N400 ERP component analysis and b) coherence analyses in four frequency bands (theta, alpha, beta, and gamma) before and after the presentation of the target word. We found that younger adults showed an N400 effect only in strongly-constrained conditions, whereas older adults showed an effect in both strongly- and weakly-constrained conditions. In terms fo coherence, pre-onset, we found that older adults showed a predictive effect in alpha, beta, and theta coherence, but not in gamma. Younger adults showed a predictive effect only in gamma frequency. Post-onset, older adults did not show an effect at any frequency. Our findings are discussed within the framework of hierarchical predictive coding.