Developing functional sodium (Na) imaging (fNaI): a direct window into neuronal excitability in health and diseased brain

血氧水平依赖（BOLD）功能磁共振成像（fMRI）通过间接测量大脑活动而主导了神经科学。它允许标测由于神经元激活导致的血容量和血流量增加引起的MR信号变化，尽管它受试者特定血液动力学因素的影响。直接测量神经元活动将有很大的好处，包括激活区域的更具体的定位和对背景脑血管因素的依赖性降低。目前的技术可以使用3 T MRI测量人脑中的钠浓度。该项目将开发用于直接测量神经元活动的关键成分（即钠通量）的采集、重建和分析。将探索人工智能和机器学习用于钠图像重建和活动检测。如果动态重复的钠成像能够成功地检测特定任务引起的钠离子浓度变化，那么它将成为研究大脑功能的更直接的方法，补充BOLD-fMRI。初步结果非常令人鼓舞，在世界范围内尚属首次。博士将需要探索钠通量的生理基础，并可能与现实的模型来解释检测到的信号变化。多发性硬化症的临床应用将探索功能性钠成像的临床可行性及其潜在影响。

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has dominated neuroscience by indirectly measuring brain activity. It allows mapping of MR signal changes due to increased blood volume and flow resulting from neuronal activation, although it is affected by subject specific haemodynamic factors. Measuring neuronal activity directly would have major benefits, including a more specific localisation of activation areas and a reduced dependency on background cerebrovascular factors. Current technology makes it possible to measure sodium concentration in the human brain using 3T MRI. This project will develop acquisition, reconstruction and analysis for directly measure a key component of neuronal activity, i.e. sodium flux. AI and machine learning will be explored for sodium image reconstruction and activity detection. If sodium imaging, dynamically repeated, was successful in detecting sodium ion concentration changes evoked by specific tasks, it would become a more direct way of investigating brain function, complementing BOLD-fMRI. Preliminary results are very encouraging and are a first world-wide. The PhD will need to explore the physiological basis of sodium flux and potentially work with realistic models to explain the detected signal changes. Clinical applications in multiple sclerosis will explore clinical feasibility of functional sodium imaging and its potential impact.