Volumetric and connectivity measures of navigation and memory skill acquisition

项目摘要 认知神经科学的一个基石涉及认知专业知识可以 通过灰质的局灶性变化进行追踪。一个提议的机制是如何实现这一点 可能起作用的是，突触可塑性的变化导致树突生长，进而 导致MRI可观察到的灰质体积增大。与此一致的是， 一项极具影响力的研究表明，经常使用认知能力的出租车司机 地图及其导航环境的记忆，具有放大的后部 海马体与健康对照组和公交车司机进行比较。最近的一次大型- 然而，来自共同PI Weisberg的样本研究发现，海马体之间没有相关性 在类似城市的虚拟现实任务中的音量和导航性能。最近的工作有 也让人怀疑灰质体积的变化是否是衡量 可塑性，因为它们也可能涉及血管形成的变化和其他难以 隔离因素。与任务相关的功能连接和静止状态连接都提供了一种新颖的 和强大的手段来分析大脑的变化，潜在地更好地与 可塑性。可以说，这样的衡量标准也可以更好地跟踪变化 在技能获取方面。在这里，我们建议解决上述问题，并另外 尝试分离导航和记忆功能，方法是使用一组 参与者接受密集的定向训练，另一组接受 情景记忆强化训练(目标1)。我们将接受培训前和培训后 测量结构性脑体积、与任务相关的功能连接和休息 状态连通性，以确定新的认知技能习得是否以及如何影响 这些神经测量。此外，我们将收集脑部结构扫描和行为 从已发表的研究中得出的方法，试图了解大脑区域与 具有导航和记忆性能(目标2)。这将允许我们执行一个meta- 对大样本研究的分析，以确定局部脑体积如何相关 在这两个重要的认知功能中，个体具有差异性。预期中的 这一建议的结果是更好地理解局灶性灰质与 核磁共振测量的连接性与记忆和导航技能有关。是这样的 结果可能通过以下方式影响对中风患者的认知或刺激治疗 洞察哪些大脑区域或网络是缓解认知障碍的目标 拒绝。

Project Abstract A cornerstone of cognitive neuroscience involves the idea that cognitive expertise can be tracked through focal changes in gray matter. One proposed mechanism for how this could work is that changes in synaptic plasticity result in dendritic growth, which in turn result in volumetric increase in gray matter observable with MRI. Consistent with this, one highly influential study suggested that taxi-drivers, who routinely employ cognitive maps and their memory of environments to navigate, have an enlarged posterior hippocampus compared to healthy control subjects and bus-drivers. A recent large- sample study from co-PI Weisberg, however, found no correlation between hippocampal volume and navigational performance in a city-like virtual reality task. Recent work has also cast doubt on whether gray matter volume changes are an appropriate measure of plasticity as they also likely involve changes in vascularization and other difficult to isolate factors. Both task-related functional and resting state connectivity offer a novel and powerful means of assaying brain wide changes potentially better related to plasticity. Such measures could also arguably be better candidates for tracking changes in skill acquisition. Here, we propose to resolve the issues above, and additionally attempt to separate navigation vs. memory functions, by having one group of participants undergo intensive training in orientation and another group undergo intensive training in episodic memory (Aim 1). We will obtain pre- and post-training measures of structural brain volume, task-related functional connectivity, and resting state connectivity to determine whether and how novel cognitive skill acquisition affects these neural measures. In addition, we will collect structural brain scans and behavioral measures from published studies to attempt understand what brain regions correlate with navigation and memory performance (Aim 2). This will allow us to perform a meta- analysis of a large sample of studies to determine how regional brain volume correlates with individual variability in these two important cognitive functions. The expected outcomes of this proposal are a better understanding of how focal gray matter vs. connectivity, as measured with MRI, relate to memory vs. navigation skills. Such outcomes could influence cognitive or stimulation therapies for stroke patients by providing insight into what brain regions or networks to target to mitigate cognitive decline.