The White Matter Correlates of Domain-Specific Working Memory

EasyChair Preprint 6367

Abstract

Prior evidence suggests separable, domain-specific working memory (WM) buffers for maintaining phonological (i.e., speech sound) and semantic (i.e., meaning) information. The phonological WM buffer’s proposed location is the left supramarginal gyrus, whereas semantic WM has been related to the left inferior frontal gyrus, middle frontal gyrus, and angular gyrus. We investigated the role of white matter tracts connecting these regions in supporting WM. We predicted left arcuate fasciculus (AF) integrity to predict phonological WM and left inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), middle longitudinal fasciculus (MLF), and uncinate fasciculus (UF) integrity to predict semantic WM. For 24 individuals with aphasia following left hemisphere stroke, single word processing, phonological WM, and semantic WM scores were available. T1 and diffusion weighted (b = 800 sec/mm²) scans were also obtained. Left and right hemisphere tracts were dissected with ROIs drawn manually in native space. On the left, correlations with at least marginal significance were for single word semantic processing and FA values for the MLF and UF. On the right, FA values for the IFOF correlated with single word phonological processing, and FA values for the IFOF, ILF and UF correlated with semantic WM. In multiple regressions controlling for single word processing, relations between semantic WM and FA values remained marginally significant for the right ILF and UF (both p’s=.054). Future work will assess a larger sample of participants and analyze relationships between WM and subsections of the AF. Right hemisphere relations to semantic WM were a novel result and suggest possible reorganization to the right hemisphere. To address the tracts’ role prior to brain damage, we will investigate correlations between tract integrity and WM in healthy age-matched individuals.

Keyphrases: Diffusion Tensor Imaging, Neuroplasticity, phonology, semantics, white matter, word processing, working memory

@booklet{EasyChair:6367,
  author    = {Autumn Horne and Talha Arif and Suravi Sarkar and Cat Grimme and Randi Martin},
  title     = {The White Matter Correlates of Domain-Specific Working Memory},
  howpublished = {EasyChair Preprint 6367},
  year      = {EasyChair, 2021}}