Poster B27, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
How cognitive abilities modulate the brain network for auditory lexical access in healthy seniors
Stefan Heim1,2, Barbara Wellner1,2, Bruno Fimm2, Christiane Jockwitz1,3, Svenja Caspers1,3, Katrin Amunts1,3;1Institute for Neuroscience and Medicine (INM-1), Research Centre Jülich, Germany, 2RWTH Aachen University, 3Heinrich Heine University Düsseldorf
Word-finding difficulties are a common phenomenon in healthy ageing. The causes seem to be deficits in lexical access rather than deficient representations of words and their meaning. Since ageing persons may also show decline in other cognitive functions such as executive control or attention, the question is in how far cognitive factors contribute to deficits in lexical access. The present study investigated the neural mechanisms of auditory lexical access in healthy elderly subjects with particular focus on modulation effects of general intelligence, selective attention, verbal fluency, and spoken language comprehension. Thirty-three older adults (mean age 62.9 years) performed an auditory lexical decision task during an event-related fMRI session. In addition, an extensive battery of neuropsychological tests was conducted. Performances in cognitive tests of auditory selective attention, verbal fluency, auditory comprehension, and general intelligence served as regressors for the BOLD contrast of auditory lexical access. The cortical network of auditory lexical access comprised the bilateral inferior frontal sulcus and inferior frontal gyrus (in particular the left area 44), the bilateral Heschl’s gyrus (areas Te1.0 and Te1.2), the bilateral superior temporal gyrus (partially overlapping with the right area Te3), the bilateral superior temporal sulcus, the left middle temporal gyrus, the bilateral parietal operculum (overlapping with the right area OP 4), parts of the bilateral precentral (areas 4a and 4p) and postcentral gyri (partially overlapping with the left area 3b and the right area 3a), the left inferior parietal lobule (area PFcm), and parts of the bilateral superior frontal gyrus. In addition, subcortical activation occurred in the right anterior cingulate gyrus, and the right insula. This cortical network was differentially modulated by the cognitive functions. Positive modulatory effects were found for auditory selective attention, verbal fluency, and general intelligence. In contrast, auditory language comprehension only exerted negative modulation. Among these factors, only the effect of verbal fluency was reduced over the period of 12 months in a reduced sample of 28 participants, with all other effects remaining stable. In conclusion, in correspondence to the data of healthy young adults, the general network of auditory lexical access seems to be preserved until at least the age of early 70. The present results link cognitive performance to a functional cortical network of speech recognition and thus complemented the current literature of structural cortical changes at the interface of language, cognition, and brain during healthy ageing.
Themes: Meaning: Lexical Semantics, Speech Perception
Method: Functional Imaging