Multi-parametric vascular and metabolic MRI for the study of cerebral plasticity

众所周知，大脑是一个高度可塑性的器官，这意味着它具有终身改变结构和功能的能力，在接受训练以学习新任务后，并对损伤和生活方式(如饮食或运动)等生理变化做出反应。例如，磁共振成像(MRI)表明，学习杂耍等运动任务可以导致大脑结构和功能的变化。但是，尽管我们知道大脑会发生变化，但这些变化的程度、生物学性质、这些变化是否会长期保持以及是否可以利用它们来恢复疾病，都是正在进行的辩论的主题。这是因为大脑的可塑性涉及多个微妙的结构、血管和代谢变化。众所周知，使用单一的MRI技术和小样本量在人类身上研究这些变化是非常困难的。*加拿大的大多数核磁共振研究是使用3特斯拉(T)磁体进行的，在这个磁场强度下，存在许多技术来研究大脑结构和功能。不幸的是，研究中常用的许多技术只提供了关于MRI信号背后的生物机制的有限信息。虽然不太常见，但存在新的和先进的技术来查看更具体的信息，如脑血流量、血容量、氧代谢、静脉和灰质微结构。此外，还可以使用更高的磁场(7T)，结合这些先进的技术，以更高的特异性和更高的分辨率帮助我们了解发挥作用的生物机制。*在这里，我们建议在3T和7T使用这些先进的技术，以更好地了解塑性过程。在这个项目中，我们将通过扩展我们过去开发的模型来继续开发现有的先进血管和代谢技术。此外，我们将结合先进的MRI技术测量大脑结构、血管解剖和功能以及新陈代谢，以创建更好地捕捉生物可塑性过程的新指标。这些新的指标将与更成熟的技术一起用于研究在运动学习任务中表征大脑可塑性的复杂模式。这些研究将涉及双手钢琴演奏和手指握持任务，并将有助于建立在7T和3T下开发的技术的有效性和敏感性。未来，这些技术还将被用于研究与年龄相关的可塑性和运动诱导的可塑性。鉴于可塑性是正常和异常大脑功能的基本过程，鉴于人们对神经成像的兴趣与日俱增，这里开发的技术工作有望导致大量被引用的出版物。此外，通过培训年轻科学家在这些领域拥有多才多艺和新颖的专业知识，该计划将通过提高他们的需求来促进他们的职业生涯，并为促进加拿大的创新科学做出贡献。

The brain is known to be a highly plastic organ, meaning that it has the lifelong ability to alter its structure and function following training to learn a new task and in response to physiological changes such as injury and lifestyle (e.g. diet or exercise). For example, it has been shown using magnetic resonance imaging (MRI) that learning a motor task such as juggling can lead to changes in brain structure and function. But while we know that the brain changes, the extent of these changes, their biological nature, whether these changes are maintained in the long term and whether they can be harnessed for disease recovery are all the subject of ongoing debate. This is because brain plasticity involves multiple subtle structural, vascular and metabolic changes. These changes are notoriously difficult to study in humans using single MRI techniques and small sample sizes. ***Most MRI research in Canada is done using 3 tesla (T) magnets, and many techniques exist at this field strength to study brain structure and function. Unfortunately, many of the techniques commonly used in research provide only limited information about the biological mechanisms that underlie the MRI signals. While less common, new and advanced techniques exist to look at more specific information such cerebral blood flow, blood volume, oxygen metabolism, veins and grey matter microstructure. Furthermore, higher magnetic fields (7T) can also be used, in combination with these advanced techniques, to help us understand the biological mechanisms at play with greater specificity and higher resolution. ***Here, we propose to use these advanced techniques at 3T and 7T to better understand the plasticity process. In this program, we will continue to develop the existing advanced vascular and metabolic techniques by extending models we have developed in the past. Also, we will combine advanced MRI techniques measuring brain structure, blood vessel anatomy and function, and metabolism to create novel metrics that better capture the biological plasticity process. These new metrics will be used, along with more established techniques, to study the complex patterns that characterize brain plasticity during motor learning tasks. These studies will involve bimanual piano playing and a finger pinching task, and will help establish the validity and sensitivity of the techniques developed here at 7T and at 3T. In the future, these techniques will also be used to study age-related and exercise-induced plasticity. Given that plasticity is an essential process of normal and abnormal brain function, and given the increasing interest in neuroimaging, the technical work developed here is expected to lead to highly cited publications. Furthermore, by training young scientists to have versatile and novel expertise in these fields, this program will promote their careers by making them in high demand and contribute to fostering innovative science in Canada.