Background: Lateralization of visuospatial attention, referred as pseudoneglect manifests as a mostly leftward attentional bias in healthy people, and is stablished by the lateralized activation of attentional network. Due MS, the forming lesions in white matter and the atrophy affecting the gray matter alters patientā€™s cognitive ability.
Objectives: In this thesis, we aim to demonstrate how invariant the visuospatial attention in healthy people is, and how the brain laterization on microstructural level contributes to the behavioral manifestation. Furthermore, we set out to reveal how visuospatial attention differs in MS patients, and what structural brain alterations can be identified in association with the behavior.
Methods: In Study 1, tract-based spatial statistics was used to investigate how lateralization of white matter microstructure, characterized by fractional anisotropy, associated with visuospatial attentional bias in 20 healthy controls. Structural connectivity of white matter tracts associated with the extent and lateralization of visuospatial attentional bias was also investigated. In addition,
healthy subjects performed Landmark task on three consecutive days in order to measure the reproducibility of pseudoneglect. In Study 2, Fierro scores of 35 multiple sclerosis patients and 20 healthy controls were compared. Using voxel-based morphometry and lesion-symptom mapping, we aimed to identify the structural background of the altered attentional bias in MS patients. Association between visuospatial attention and clinical or cognitive scores of MS patients were also analyzed.
Results: In Study 1, the integrity of white matter microstructure in parietal lobe significantly correlated (p