Original Research ARTICLE
Age Differences in Encoding-Related Alpha Power Reflect Sentence Comprehension Difficulties
- 1Max Planck Institute for Human Cognitive and Brain Sciences, Germany
When sentence processing taxes verbal working memory, comprehension difficulties arise. This is specifically the case when processing resources decline with advancing adult age. Such decline likely affects the encoding of sentences into working memory, which constitutes the basis for successful comprehension. To assess age differences in encoding-related electrophysiological activity, we recorded the electroencephalogram from three age groups (24, 43, 65 years). Using an auditory sentence comprehension task, age differences in encoding-related oscillatory power were examined with respect to the accuracy of the given response. That is, the difference in oscillatory power between correctly and incorrectly encoded sentences, yielding subsequent memory effects (SME), was compared across age groups. Across age groups, we observed an age-related SME inversion in the alpha band from a power decrease in younger adults to a power increase in older adults. We suggest that this SME inversion underlies age-related comprehension difficulties. With alpha being commonly linked to inhibitory processes, this shift may reflect a change in the cortical inhibition–disinhibition balance. A cortical disinhibition may imply enriched sentence encoding in younger adults. In contrast, resource limitations in older adults may necessitate an increase in cortical inhibition during sentence encoding to avoid an information overload. Overall, our findings tentatively suggest that age-related comprehension difficulties are associated with alterations to the electrophysiological dynamics subserving general higher cognitive functions.
Keywords: Aging, encoding, sentence comprehension, alpha band, Neural oscillations
Received: 20 Mar 2019;
Accepted: 04 Jul 2019.
Edited by:Rubem C. Guedes, Federal University of Pernambuco, Brazil
Reviewed by:Yang-soo Yoon, Baylor University, United States
Linda Drijvers, Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Netherlands
Copyright: © 2019 Beese, Vassileiou, Friederici and Meyer. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mx. Caroline Beese, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, 04103, Lower Saxony, Germany, email@example.com