Age-related differences in resolving semantic and phonological competition during receptive language tasks

Abstract

Receptive language (e.g., reading) is largely preserved in the aging brain, and semantic processes in particular may continue to develop throughout the lifespan. We investigated the neural underpinnings of phonological and semantic retrieval in older and younger adults during receptive language tasks (rhyme and semantic similarity judgments). In particular, we were interested in the role of competition on language retrieval and varied the similarities between a cue, target, and distractor that were hypothesized to affect the mental process of competition. Behaviorally, all participants responded faster and more accurately during the rhyme task compared to the semantic task. Moreover, older adults demonstrated higher response accuracy than younger adults during the semantic task. Although there were no overall age-related differences in the neuroimaging results, an Age × Task interaction was found in left inferior frontal gyrus (IFG), with older adults producing greater activation than younger adults during the semantic condition. These results suggest that at lower levels of task difficulty, older and younger adults engaged similar neural networks that benefited behavioral performance. As task difficulty increased during the semantic task, older adults relied more heavily on largely left hemisphere language regions, as well as regions involved in perception and internal monitoring. Our results are consistent with the stability of language comprehension across the adult lifespan and illustrate how the preservation of semantic representations with aging may influence performance under conditions of increased task difficulty.

Learning and memory in the aging brain: The function of declarative and nondeclarative memory over the lifespan.

“…However, as task difficulty increased during the semantic task, older adults relied more heavily on left hemisphere regions, as well as regions involved in perception and strategic monitoring. Zhuang et al (2016) suggest that these results are consistent with the stability of language comprehension across the adult life span and illustrate how the preservation of semantic representations with age may influence performance during high task difficulty.…”

Age-related differences in conversational discourse abilities A comparative study

“… 72 - 74 While younger adults focus on the text itself and its microstructure, older individuals are more likely to cling to the general idea of the text, suggesting difficulty in understanding nuance and/or specific utterances during a discourse task. 75 , 76 …”

Narrative Discourse in Young and Older Adults: Behavioral and NIRS Analyses

“…This difference may be due to the longer time needed to read the text or a greater need for attentional resources. It also probably indicates an attentional effort in semantic processing (Zhuang et al, 2016 ). The prefrontal cortex as a whole is known to be a major association area, having a pivotal role in the synthesis of the multifaceted information generated by the brain (Kandel et al, 2000 ).…”

“…Story comprehension entails a network of frontal, temporal and cingulate areas, which also are association areas (Mar, 2004 ). The anterior temporal lobes and left middle temporal gyrus could be involved in the semantic integration and interpretation of text in discourse as they are only activated while listening or reading meaningful texts or sentences (Mazoyer et al, 1993 ; Ferstl et al, 2008 ; Perfetti and Frishkoff, 2008 ; Bowman and Dennis, 2015 ; Zhuang et al, 2016 ). The prefrontal cortex, especially the superior dorsomedial prefrontal cortex, may be involved in the integration of one’s knowledge or when inferences from earlier parts of the discourse are needed, thus contributing to the maintenance of global coherence of texts (Schmalhofer and Perfetti, 2007 ; Perfetti and Frishkoff, 2008 ; Miotto et al, 2014 ; Bowman and Dennis, 2015 ).…”

“…Aging is known to have an impact on many cognitive functions, some of which, like working memory, are involved in discourse comprehension (Brébion, 2003 ; DeDe et al, 2004 ; Payne and Stine-Morrow, 2017 ). Among other things, elderly participants seem to rely more on the gist of the text and the situation model while performing comprehension tasks, while younger participants rely more on the textbase and microstructure (Radvansky et al, 2001 ; Ferstl, 2006 ; Radvansky and Dijkstra, 2007 ; Magliano et al, 2012 ; Davis et al, 2015 ; Zhuang et al, 2016 ). On the other hand, it seems that the characteristics of a text, especially its semantic load, highly influence the capacities of older adults to recall the microstructure and macrostructure.…”