Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32605, USA.
NASA Langley Research Center, Hampton, VA, USA.
Sci Rep. 2023 Mar 8;13(1):3842. doi: 10.1038/s41598-023-30766-x.
Mobility decline is a major concern for older adults. A key component of maintaining mobility with advancing age is the ability to learn and adapt to the environment. The split-belt treadmill paradigm is an experimental protocol that tests the ability to adapt to a dynamic environment. Here we examined the magnetic resonance imaging (MRI) derived structural neural correlates of individual differences in adaptation to split-belt walking for younger and older adults. We have previously shown that younger adults adopt an asymmetric walking pattern during split-belt walking, particularly in the medial-lateral (ML) direction, but older adults do not. We collected T[Formula: see text]-weighted and diffusion-weighted MRI scans to quantify brain morphological characteristics (i.e. in the gray matter and white matter) on these same participants. We investigated two distinct questions: (1) Are there structural brain metrics that are associated with the ability to adopt asymmetry during split-belt walking; and (2) Are there different brain-behavior relationships for younger and older adults? Given the growing evidence that indicates the brain has a critical role in the maintenance of gait and balance, we hypothesized that brain areas commonly associated with locomotion (i.e. basal ganglia, sensorimotor cortex, cerebellum) would be associated with ML asymmetry and that older adults would show more associations between split-belt walking and prefrontal brain areas. We identified multiple brain-behavior associations. More gray matter volume in the superior frontal gyrus and cerebellar lobules VIIB and VIII, more sulcal depth in the insula, more gyrification in the pre/post central gyri, and more fractional anisotropy in the corticospinal tract and inferior longitudinal fasciculus corresponded to more gait asymmetry. These associations did not differ between younger and older adults. This work progresses our understanding of how brain structure is associated with balance during walking, particularly during adaptation.
行动能力下降是老年人面临的主要问题之一。随着年龄的增长，保持行动能力的一个关键因素是学习和适应环境的能力。分带跑步机范式是一种测试适应动态环境能力的实验方案。在这里，我们研究了磁共振成像（MRI）衍生的结构神经相关性，以了解年轻人和老年人对分带行走适应的个体差异。我们之前已经表明，年轻人在分带行走时会采用不对称的行走模式，特别是在横向（ML）方向，但老年人不会。我们收集了 T[Formula: see text]-加权和扩散加权 MRI 扫描，以量化同一参与者的大脑形态特征（即灰质和白质）。我们研究了两个不同的问题：（1）是否存在与在分带行走中采用不对称性相关的结构脑指标；（2）年轻人和老年人的大脑-行为关系是否不同？鉴于越来越多的证据表明大脑在维持步态和平衡方面起着关键作用，我们假设与运动相关的大脑区域（即基底节、感觉运动皮层、小脑）与 ML 不对称性相关，并且老年人在分带行走和前额叶大脑区域之间表现出更多的关联。我们确定了多个大脑-行为关联。额上回、小脑小叶 VIIB 和 VIII 区的灰质体积更多，脑岛的脑沟深度更大，中央前回/后回的脑回更复杂，皮质脊髓束和下纵束的各向异性分数更高，与更大的步态不对称性相关。这些关联在年轻人和老年人之间没有差异。这项工作增进了我们对大脑结构如何与行走时的平衡相关的理解，特别是在适应过程中。
