White matter microstructure in the superior longitudinal fasciculus predicts alpha modulation during visuospatial working memory encoding

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Joel P. Diaz-Fong^1,2,3 (joel.diaz@mail.utoronto.ca), Agatha Lenartowicz¹, Holly Truong¹, Giulia C. Salgari⁴, Robert M. Bilder¹, James McGough¹, James T. McCracken¹, Sandra K. Loo¹; ¹Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, ²Institute of Medical Science, University of Toronto, ³Centre for Addiction and Mental Health, ⁴University of Central Florida

Working memory (WM) is a neurocognitive function affected in ADHD, and studies have shown aberrant alpha modulation to be related to these deficits. The second branch of the superior longitudinal fasciculus (SLF-II) is thought to have a functional role in visuospatial processing, making it a structure of interest. This analysis investigates the underlying white matter structure contributing to aberrant alpha modulation during visuospatial WM encoding in children with ADHD. We hypothesize that the white matter microstructure in the SLF-II will predict mid-occipital alpha (8-12 Hz) event-related decreases (ERD) during WM encoding. 107 children (7-15 years, 10.49±2.1, 65.4% males) with EEG and diffusion MRI were identified from participants who enrolled in research studies at the TRECC Center, including typically developing children (n=36) and children with ADHD (n=71). Forty-channel EEG was recorded while participants performed a visuospatial WM task. A mid-occipital alpha component derived from ICA decomposition was extracted from a previously published analysis. Diffusion MRI was preprocessed using FSL, and tractography was performed using FreeSurfer’s TRACULA. Average fractional anisotropy (FA) and mean diffusivity (MD) measures were extracted from the SLF-II tract. Two separate linear regressions were performed to test if average DTI measures (FA and MD) predict mid-occipital alpha ERD. Both average FA (β=-0.30, p=0.046) and average MD (β=0.41, p=0.011) significantly predict alpha ERD. Group by DTI measures were not significant. Results indicate that the microstructure of the SLF-II predicts visuospatial WM encoding as measured by alpha ERD. These results provide insights into the structure-function relationship involved in visuospatial WM encoding.

Topic Area: EXECUTIVE PROCESSES: Working memory