Neural correlates of within-session practice effects in mild motor impairment after stroke: a preliminary investigation

Exp Brain Res. 2021 Jan;239(1):151-160. doi: 10.1007/s00221-020-05964-y. Epub 2020 Nov 1.

Abstract

While the structural integrity of the corticospinal tract (CST) has been shown to support motor performance after stroke, the neural correlates of within-session practice effects are not known. The purpose of this preliminary investigation was to examine the structural brain correlates of within-session practice effects on a functional motor task completed with the more impaired arm after stroke. Eleven individuals with mild motor impairment (mean age 57.0 ± 9.4 years, mean months post-stroke 37.0 ± 66.1, able to move ≥ 26 blocks on the Box and Blocks Test) due to left hemisphere stroke completed structural MRI and practiced a functional motor task that involved spooning beans from a start cup to three distal targets. Performance on the motor task improved with practice (p = 0.004), although response was variable. Baseline motor performance (Block 1) correlated with integrity of the CST (r = - 0.696) while within-session practice effects (change from Block 1 to Block 3) did not. Instead, practice effects correlated with degree of lesion to the superior longitudinal fasciculus (r = 0.606), a pathway that connects frontal and parietal brain regions previously shown to support motor learning. This difference between white matter tracts associated with baseline motor performance and within-session practice effects may have implications for understanding response to motor practice and the application of brain-focused intervention approaches aimed at improving hand function after stroke.

Keywords: Diffusion imaging; Motor practice; Stroke; Upper extremity.

MeSH terms

  • Diffusion Tensor Imaging
  • Humans
  • Middle Aged
  • Motor Disorders*
  • Pyramidal Tracts / diagnostic imaging
  • Stroke* / complications
  • White Matter*