Structural Covariance of the Ipsilesional Primary Motor Cortex in Subcortical Stroke Patients with Motor Deficits

Abstract

The analysis of structural covariance has emerged as a powerful tool to explore the morphometric correlations among broadly distributed brain regions. However, little is known about the interactions between the damaged primary motor cortex (M1) and other brain regions in stroke patients with motor deficits. This study is aimed at investigating the structural covariance pattern of the ipsilesional M1 in chronic subcortical stroke patients with motor deficits. High-resolution T1-weighted brain images were acquired from 58 chronic subcortical stroke patients with motor deficits (29 with left-sided lesions and 29 with right-sided lesions) and 50 healthy controls. Structural covariance patterns were identified by a seed-based structural covariance method based on gray matter (GM) volume. Group comparisons between stroke patients (left-sided or right-sided groups) and healthy controls were determined by a permutation test. The association between alterations in the regional GM volume and motor recovery after stroke was investigated by a multivariate regression approach. Structural covariance analysis revealed an extensive increase in the structural interactions between the ipsilesional M1 and other brain regions in stroke patients, involving not only motor-related brain regions but also non-motor-related brain regions. We also identified a slightly different pattern of structural covariance between the left-sided stroke group and the right-sided stroke group, thus indicating a lesion-side effect of cortical reorganization after stroke. Moreover, alterations in the GM volume of structural covariance brain regions were significantly correlated to the motor function scores in stroke patients. These findings indicated that the structural covariance patterns of the ipsilesional M1 in chronic subcortical stroke patients were induced by motor-related plasticity. Our findings may help us to better understand the neurobiological mechanisms of motor impairment and recovery in patients with subcortical stroke from different perspectives.

Fine motor control improves in older adults after 1 year of piano lessons: Analysis of individual development and its coupling with cognition and brain structure

“…This assumes that functionally or structurally connected brain regions also covary in their morphology and that environmental factors influence their coordinated development and thus covariance (for a review, see Alexander‐Bloch & Giedd, 2013). For example, in patients with stroke, alterations in structural covariance were found in a network including the cortico‐striato‐thalamical loop and diverse sensorimotor cortices (Abela et al, 2015) and between the ipsilesional M1 and motor as well as non‐motor brain regions (Chen et al, 2022).…”

Morphological alterations of contralesional hemisphere relate to functional outcomes after stroke

“…Recently, researchers come to realize that morphologic alterations of brain regions beyond the lesion are also crucial for clinical recovery (Al Harrach et al, 2019; Merino‐Serrais et al, 2022). For instance, a decrease in grey matter volume (GMV) in motor‐related regions typically indicates poor motor performance after stroke (Chen et al, 2022; Keller et al, 2020). Several studies have associated thickening of contralesional cortex beyond primary motor and sensory areas with the ability of life independence and sensorimotor recovery after stroke (Liu et al, 2015; Rojas Albert et al, 2022), while some studies found no clinical associations of contralesional cortical thickness (CT) (Cheng et al, 2020; Liu et al, 2020).…”

Dynamic brain activity states of memory impairment in stroke patients with varying motor outcomes

“…Motor and cognitive impairments are prevalent after stroke (Zhao et al, 2018;Shekhar et al, 2021;Chen et al, 2022), even in patients with mild strokes (Einstad et al, 2021). Compared to motor function injuries, cognitive function injuries have the characteristics of being concealed and delayed, resulting in patients with cognitive impairment not seeking medical treatment promptly.…”