Using diffusion tensor imaging to identify the structural neural correlates of visuospatial and motor skill learning processes

项目摘要/摘要 在治疗前测试特定认知障碍的简单行为可能会识别出 从运动康复疗法中得到的好处很少，甚至没有。研究表明，老年人往往会 与年轻人相比，学习运动技能的速度更慢，程度也更小。鉴于人口老龄化，还 经历认知衰退，五分之一的老年人(65岁)有某种形式的认知障碍， 较差的运动学习能力可能部分与认知障碍的存在有关，而不是 按时间顺序排列的年龄。我们最近表明，视觉空间障碍，特别是可能会扰乱老年人的 学习和保持新的运动技能的能力；在之前的研究中，我们使用了视觉空间测试来评估 只有视觉感知和视觉构建能力，而视觉空间领域要广泛得多(例如， 视觉记忆和学习、空间注意力等)。拟议的研究将通过以下方式扩展我们先前的发现 评估视觉空间功能的哪个方面最能预测运动学习能力，并通过本地化 构成这种预测关系的神经底物。像运动学习能力，白色的衡量标准 大脑中的物质随着年龄的增长而减少，但仍然非常多变。最近的研究表明， 顶叶和额叶皮质之间的白质完整性可以解释几项运动学习任务中的差异。 由于这些结构和通路也涉及视觉空间功能，我们假设 视觉空间测试具有预测价值，因为它们探测运动关键神经机制的健康状况 学习。一个候选的白质通路可能是右上纵束(SLF)，因为它 连接视觉运动过程中涉及的皮质。然而，最近调查这种关系的研究 在视觉空间功能和右侧SLF结构完整性之间报告了相互冲突的发现 视觉空间测试对右侧SLF健康状况的预测能力仍不清楚。根据我们的试点数据，我们的 中心假设是视觉空间和运动学习过程以某种方式整合在正确的SLF中 这样视觉空间测试将预测运动技能的保持。为了验证这一假设，我们将扩展我们的 先前的发现通过使用跨越视觉空间域广度的综合测试电池， 并跟踪一个月内的运动技能保持情况。我们将使用结构神经成像技术来 量化SLF的完整性，然后评估其与运动技能保持和视觉空间功能的关系。这个 该项目的结果将对多个神经科学领域产生多方面的影响：我们将能够 促进对白质在运动学习和视觉空间整合中作用的神经解剖学理解， 为临床实践提供循证工具，以预测谁将(或不会)对运动作出反应 康复，并潜在地确定正确的SLF作为神经康复的神经解剖学目标。

Project Summary/Abstract The simple act of testing for specific cognitive impairments prior to therapy may identify older adults who will receive little to no benefit from the motor rehabilitation regimen. Studies have shown that older adults tend to learn motor skills at a slower rate and to a lesser extent than younger adults. Given aging populations also experience cognitive decline, where one in five older adults (age>65) have some form of cognitive impairment, poorer motor learning capacity may, in part, be linked to the presence of cognitive impairments rather than to chronological age. We recently showed that visuospatial impairment, specifically, may disrupt an older adult’s ability to learn and retain new motor skills; in this previous study, we used a visuospatial test that evaluates only visual perception and visuo-constructional ability, whereas the visuospatial domain is much broader (e.g., visual memory and learning, spatial attention, etc.). The proposed research will extend our previous findings by evaluating which aspect of visuospatial function is most predictive of motor learning capacity, and by localizing the neural substrate that underlies this predictive relationship. Like motor learning capacity, measures of white matter within the brain decline with age but are still quite variable. Recent studies have shown that variance in white matter integrity between parietal and frontal cortices explains variance in several motor learning tasks. Since these structures and pathways are also involved in visuospatial functions, we hypothesize that visuospatial tests have predictive value because they probe the health of critical neural mechanisms of motor learning. One candidate white matter pathway may be the right superior longitudinal fasciculus (SLF), as it connects cortices implicated in visuomotor processes. However, recent studies investigating the relationship between visuospatial function and right SLF structural integrity report conflicting findings such that the predictive power of visuospatial testing on right SLF health remains unclear. Based on our pilot data, our central hypothesis is that visuospatial and motor learning processes are integrated in the right SLF in a manner such that visuospatial testing will predict motor skill retention. To test this hypothesis, we will expand on our previous findings by using a comprehensive testing battery that spans the breadth of the visuospatial domain, and track motor skill retention over a one-month period. We will use structural neuroimaging techniques to quantify SLF integrity and then evaluate its relationship with motor skill retention and visuospatial function. The results of this project will have multifaceted implications across multiple neuroscience fields: we will be able to advance neuroanatomical understanding of white matter’s role in motor learning and visuospatial integration, provide clinical practice with an evidence-based tool to predict who will (or will not) respond to motor rehabilitation, and potentially identify the right SLF as a neuroanatomical target for neurorehabilitation.