Effects of Lifelong Musicianship on White Matter Integrity and Cognitive Brain Reserve

Abstract

There is a significant body of research that has identified specific, high-end cognitive demand activities and lifestyles that may play a role in building cognitive brain reserve, including volume changes in gray matter and white matter, increased structural connectivity, and enhanced categorical perception. While normal aging produces trends of decreasing white matter (WM) integrity, research on cognitive brain reserve suggests that complex sensory-motor activities across the life span may slow down or reverse these trends. Previous research has focused on structural and functional changes to the human brain caused by training and experience in both linguistic (especially bilingualism) and musical domains. The current research uses diffusion tensor imaging to examine the integrity of subcortical white matter fiber tracts in lifelong musicians. Our analysis, using Tortoise and ICBM-81, reveals higher fractional anisotropy, an indicator of greater WM integrity, in aging musicians in bilateral superior longitudinal fasciculi and bilateral uncinate fasciculi. Statistical methods used include Fisher's method and linear regression analysis. Another unique aspect of this study is the accompanying behavioral performance data for each participant. This is one of the first studies to look specifically at musicianship across the life span and its impact on bilateral WM integrity in aging.

Keywords: cognitive reserve; diffusion tensor imaging; fractional anisotropy; musicianship; white matter integrity.

Figure 1

The superior longitudinal fasciculi (SLF) and uncinate fasciculi (UF) are related to musical proficiency and age. The sagittal striata (SS) are also related to age, but not musical proficiency. The SLF (red), UF (magenta) and SS (blue) are depicted in accordance with the ICBM-81 atlas (Mori et al., 2008)[15]. The tracts are superimposed on a T1 weighted image in the Montreal Neurological Institute 152 space. The figure uses the left-posterior-inferior convention. Legend: L, left.

Figure 2

Scatter plots and linear fits between fractional anisotropy (FA) and subjects’ ages that are affected by musical proficiency (top two rows) and tracts that may be unrelated to musical proficiency (bottom row). The vertical axes represent mean FA, and the horizontal axes represent subject age in years. The superior longitudinal fasciculus (SLF) and uncinate fasciculus (UF) tracts (top two rows) show a positive correlation between FA and age.