Manipulation and characterization of functional connectivity measured with MRI

描述(申请人提供)：功能磁共振成像(FMRI)对人脑的血液动力学波动很敏感。通过计算不同大脑区域波动之间的相关性创建的功能连接图显示，在已知强连接的区域中，相关性很高。这种相关性被认为与协调的神经活动有关。这项技术越来越多地被用于探测正常受试者和神经疾病患者的大脑活动网络。然而，血流动力学波动的生理基础以及与潜在神经活动的联系尚不清楚。我们研究的最终目标是明确确定MRI测量的功能连通性与神经活动之间的关系。很难在人类身上探索两者之间的关系，而且到目前为止，在动物身上进行的功能连接性研究很少。这项研究建议通过结合微电极记录和成像来阐明相关的MRI信号波动与啮齿动物神经活动之间的关系。记录将在图像之间进行，因此可以直接比较电相干和MRI的相关性。这项建议的具体目的是：在啮齿动物模型中通过交错微电极记录和图像采集来确定功能连通性和神经活动之间的关系。：将使用灌流、血液氧合和血容量加权磁共振来测量大鼠的功能连通性，以确定哪种血管特性是信号波动的主要来源。高碳酸血症将被诱导，以确定它是否像人类研究那样抑制连接性。呼吸和心脏周期将被记录下来，以确定它们对相关性的贡献。当麻醉水平改变以改变神经活动时，局部场电位的记录和MRI图像的采集将被交织和获取，并将计算来自每对电极的记录的一致性，并与MRI观察到的相关性进行比较。这个项目的目标是确定功能连通性和神经活动之间的关系。这是我们朝着建立功能连接图谱作为诊断和评估临床神经疾病的非侵入性工具的长期目标迈出的第一步。公共卫生相关性这个项目的目标是确定用核磁共振测量的啮齿动物的功能连通性与潜在的神经活动之间的关系。这是我们朝着建立功能连接图谱作为诊断和评估临床神经疾病的非侵入性工具的长期目标迈出的第一步。

Description (provided by applicant): Functional magnetic resonance imaging (fMRI) is sensitive to hemodynamic fluctuations in the human brain. Functional connectivity maps created by calculating the correlation between fluctuations from different brain areas show high correlation in areas that are known to be strongly connected. The correlation is presumed to be related to coordinated neural activity. This technique is increasingly used to probe networks of brain activity in both normal subjects and patients with neurological disorders. However, the physiological basis of the hemodynamic fluctuations and the connection to underlying neural activity are not well understood. The ultimate goal of our research is to definitively establish the relationship between functional connectivity measured with MRI and neural activity. It is difficult to probe the relationship between the two in humans, and few functional connectivity studies have been performed in animals to date. This study proposes to elucidate the relationship between correlated MRI signal fluctuations and neural activity by combining microelectrode recording and imaging in the rodent. Recording will occur between images, so that electrical coherence and MRI correlations can be directly compared. The specific aim of this proposal is: Determine the relationship between functional connectivity and neural activity by interleaving microelectrode recordings and image acquisition in a rodent model.: Functional connectivity will be measured in rats using perfusion, blood oxygenation, and blood-volume weighted MRI to identify which vascular property is the predominant source of signal fluctuations. Hypercapnia will be induced to determine whether it suppresses connectivity as in human studies. Respiratory and cardiac cycles will be recorded to determine their contributions to correlation. Recording of local field potentials and acquisition of MRI images will be interleaved and acquired as anesthesia level is varied to alter neural activity, and coherence in recordings from each pair of electrodes will be calculated and compared to correlation observed with MRI. The goal of this project is to determine the relationship between functional connectivity and neural activity. This is the first step toward our long-term goal of establishing functional connectivity mapping as a noninvasive tool for the diagnosis and evaluation of clinical neurological disorders. PUBLIC HEALTH RELEVANCE The goal of this project is to determine the relationship between functional connectivity measured with MRI in the rodent and the underlying neural activity. This is the first step toward our long-term goal of establishing functional connectivity mapping as a noninvasive tool for the diagnosis and evaluation of clinical neurological disorders.