Neurophysiology Imaging Facility Core: Functional and Structural MRI

磁共振成像，或称MRI，是基于由不同脑组织组成的质子的核自旋特性。通过一系列了不起的工程成就，核磁共振现在被常规用于以三维方式可视化包括大脑在内的整个身体的内部结构。也许更令人印象深刻的是，大脑中的区域血液流动、它在灰质体积中的相对比例，以及它的氧气水平，都可以在感觉和行为任务中进行评估。功能磁共振成像(FMRI)的后一种技术现在被美国和世界各地的几乎每一所主要大学的研究人员用来探索感觉加工、执行功能和社会认知。在短短20年内，功能磁共振成像革命将对人脑的研究带入了神经科学的前沿，并塑造了社会对大脑活动及其所有精神功能和功能障碍的基础的理解。 在神经生理学成像设备(NIF)中，我们试图将人类这一新领域的功能磁共振与更详细的动物脑生理学和解剖学研究联系起来，因为动物研究对于获得功能磁共振无法获得的神经回路的结构和功能的详细信息仍然至关重要。NIF是一个集中的核心设施，为三个赞助机构(NIMH、NINDS和NEI)的各种调查人员提供服务。NIF中的结构和功能成像利用了最新的尖端成像技术，允许用户将成像与其他侵入性技术相结合，例如微电极记录、药物失活或解剖轨迹追踪。在强磁场中测试动物需要开发一系列与MRI兼容的设备，包括动物椅子、约束设备、奖励发放设备、眼睛位置跟踪摄像头和手动反应键。因此，该设施为用户提供了猴子功能磁共振成像的这些和其他关键组件，允许他们以最小的开发开始他们的研究。该设施的工作人员协助调查人员进行实验设计，以及生产特定于项目的硬件(例如射频线圈)，以实现优化的数据收集。 使用过去几年开发的标准设置，该设施通常每天进行三次扫描，全部是在非人类灵长类动物身上。一些会议致力于高分辨率解剖扫描，这使研究人员能够确定电极的位置，执行手术计划，并评估药理药物的传播。此外，该设施还提供解剖学技术，如扩散张量成像(DTI)和锰管追踪，可与电生理研究或病变结合使用。垂直扫描仪中的大多数扫描都是针对神经功能的评估。通常，fMRI扫描与侵入性程序相结合，例如可逆灭活、皮质消融、药物操作、皮层脑电记录、电微刺激或来自慢性微线阵列的记录。功能性核磁共振成像和侵入性技术在清醒、行为正常的猴子身上的常规组合使NIH内壁研究计划成为执行非人类灵长类研究的独特场所。使用NIF核心设施的NIH研究人员正在研究一系列与基本神经功能、动机、决策、情绪和抑郁相关的主题。

Magnetic resonance imaging, or MRI, is based on the nuclear spin properties of protons comprising different brain tissues. Through a remarkable set of engineering achievements, MRI is now routinely used to visualize the internal structure of the entire body, including the brain, in three dimensions. Perhaps even more impressively, the regional flow of blood in the brain, its relative proportion in a volume of gray matter, and its oxygenation level, can all be evaluated during sensory and behavioral tasks. The latter technique of functional MRI (fMRI) is now used by investigators in nearly every major university in the country and around the world to explore sensory processing, executive function, and social cognition. In just two decades, the fMRI revolution has brought the study of the human brain to the forefront of neuroscience, and has shaped the societal understanding of brain activity and its basis for all mental function and dysfunction. In the Neurophysiology Imaging Facility (NIF), we attempt to link this new field fMRI in humans to more detailed studies of brain physiology and anatomy in animals, since animal studies remain crucial for obtaining detailed information the structure and function of neural circuits that fMRI cannot obtain. The NIF is a centralized core facility that offers services to a wide range of investigators in each of the three sponsoring institutes (NIMH, NINDS, and NEI). Structural and functional imaging in the NIF exploit the latest cutting-edge imaging technology, allowing users to combine imaging with other invasive techniques, such as microelectrode recordings, pharmacological inactivation, or anatomical tract tracing. Testing animals inside a strong magnetic field has required the development of a wide array of MRI-compatible equipment, including animal chairs, restraint devices, reward delivery apparatus, eye position tracking cameras, and manual response keys. The facility thus provides users with these and other critical components of monkey fMRI, allowing them to initiate their studies with minimal development on their part. The facility staff assists investigators with experimental design, as well as the production of project-specific hardware (e.g. radiofrequency coils) that allow for optimized data collection. Using a standard setup developed over the last years, the facility typically carries out three scanning sessions per day, all in nonhuman primates. Some of sessions are devoted to high-resolution anatomical scanning, which allows investigators to determine the position of their electrodes, perform surgical planning, and evaluate the spread of pharmacological agents. In addition, the facility offers anatomical techniques, such as diffusion tensor imaging (DTI) and manganese tract tracing, which can be used in combination with electrophysiological studies or lesions. Most of the scans in the vertical scanner are aimed at evaluation of neural function. Typically fMRI scans are combined with an invasive procedure, such as reversible inactivation, cortical ablation, pharmacological manipulation, electrocorticogram recordings, electrical microstimulation, or recordings from chronic microwire arrays. The routine combination of fMRI and invasive techniques in awake, behaving monkeys makes the NIH Intramural Research Program a unique site to perform nonhuman primate research. NIH investigators that use the NIF core facility are studying a wide range of topics related to basic neurological function, motivation, decision-making, emotion, and depression.