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的器官，这意味着它具有终身的能力，可以通过训练来改变其结构和功能，以学习新的任务，并对受伤和生活方式（例如饮食或运动）等生理变化做出反应。例如，磁共振成像（MRI）显示，学习杂耍等运动任务会导致大脑结构和功能的变化。但是，虽然我们知道大脑会发生变化，但这些变化的程度，它们的生物学性质，这些变化是否能长期维持，以及它们是否能被用于疾病康复，这些都是持续争论的主题。这是因为大脑的可塑性涉及多种细微的结构、血管和代谢变化。众所周知，这些变化很难用单一的MRI技术和小样本量来研究。***加拿大的大多数核磁共振研究都是使用3特斯拉(T)的磁铁进行的，在这种场强下存在许多技术来研究大脑的结构和功能。不幸的是，许多研究中常用的技术只能提供有限的关于MRI信号背后的生物机制的信息。虽然不太常见，但有新的先进技术可以观察更具体的信息，如脑血流量、血容量、氧代谢、静脉和灰质微观结构。此外，高磁场（7T）也可以与这些先进技术相结合，帮助我们以更高的特异性和更高的分辨率了解起作用的生物机制。***在这里，我们建议在3T和7T使用这些先进的技术来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，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技术来测量大脑结构、血管解剖和功能以及新陈代谢，以创造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捏捏任务，并将有助于建立在7度和3度开发的技术的有效性和敏感性。在未来，这些技术还将用于研究年龄相关和运动诱导的可塑性。鉴于可塑性是正常和异常脑功能的重要过程，鉴于对神经成像的兴趣日益增加，这里发展的技术工作有望导致高引用的出版物。此外，通过培养年轻科学家在这些领域具有多用途和新颖的专业知识，该计划将促进他们的职业发展，使他们成为高需求的人才，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.