White matter integrity in the Frontal Aslant Tract and language production in ageing

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

JIE YAN¹ (jzy5486@psu.edu), Xiaoxiao Bai, Michele Diaz; ¹Pennsylvania State University

Aging is often associated with word retrieval difficulties, and older adults describe these as one of their most frustrating experiences. However, fewer studies have examined the neural bases of these effects. Diffusion Tensor Imaging (DTI) studies have linked language production differences to dorsal white matter integrity. Here, we focus on the Frontal Aslant Tract (FAT), which connects posterior inferior frontal gyrus to more dorsal frontal and motor regions, and has been implicated in lexical retrieval and executive function aspects of language production. Specifically, a domain specialization has been proposed in which left FAT is strongly associated with speech initiation, stuttering, and verbal fluency, while right FAT is associated with domain-general executive function. In a large sample of individuals (N=83, aged 20 – 80), we examined how language performance (i.e., verbal fluency and speech elicitation tasks) and executive function (i.e., working memory and Stroop) differs across adulthood and how the Frontal Aslant Tract (FAT) contributes to this. We also examined these relationships in a control tract (corticospinal tract (CST). Behaviorally, our results showed age-related differences in language production (semantic VF switching, percent pauses in speech) and Stroop effect in accuracy, but not in working memory. DTI showed age effects in bilateral FAT and left CST. Importantly, white matter integrity in bilateral FAT was negatively related to percent pauses. However, both FAT and CST were not related to working memory and Stroop effect. Overall, our results showed bilateral FAT was related to language but did not contribute to executive function.

Topic Area: LANGUAGE: Development & aging