Robust controlled functional MRI in alert monkeys at high magnetic field: Effects of jaw and body movements
Robust controlled functional MRI in alert monkeys at high magnetic field: Effects of jaw and body movements
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DOI：
10.1016/j.neuroimage.2007.02.057
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发表时间：
2007-07-01
期刊：
影响因子：
5.7
通讯作者：
Logothetis, Nikos K.
中科院分区：
文献类型：
--
作者：
Keliris, Georgios A.;Shmuel, Amir;Logothetis, Nikos K.
功能性磁共振成像（fMRI）在非人灵长类动物的警觉性研究中具有巨大的应用潜力。它可以与侵入性技术相结合，并提供更好的理解非侵入性获得的人类大脑成像信号。然而，在最佳应用的猴子警觉功能磁共振成像的困难是多方面的，特别是在高磁场的运动和B-0的变化的影响被大大放大。为了克服这些困难，需要严格的行为控制和精心的动物训练。在这里，我们介绍了一些硬件的发展，量化的动作对功能磁共振成像数据的影响，并提出了程序的动物训练和扫描良好的控制和人为减少警觉猴子功能磁共振成像在高磁场。特别地，我们描述了用于监测下颌和身体运动以及用于精确地跟踪眼睛运动的系统。建立了身体和下颌运动与MRI图像伪影之间的联系，表明依赖于动物头部的固定不足以获得高质量的成像。定量分析表明，身体和颌骨运动事件造成大的不稳定性的fMRI时间序列。平均而言，身体运动事件造成更大的不稳定性比下颌运动事件。在下颌和身体运动事件结束后，观察剩余基线脑图像位置和信号幅度变化。基于这些发现，我们引入了一种新的行为范式，该范式依赖于训练猴子在长时间试验中保持静止。相应的分析方法丢弃了在无运动期间未获得的所有数据。基线位置和幅度偏移通过运动校正和逐个试验信号归一化来克服。在7 T下获得的数据证明了所提出的方法相对于常规扫描和分析的优点。预计这里提出的技术将被证明是有用的警觉猴子功能磁共振成像在任何磁场。(c)2007爱思唯尔公司All rights reserved.
The use of functional magnetic resonance imaging (fMRI) in alert non-human primates is of great potential for research in systems neuroscience. It can be combined with invasive techniques and afford better understanding of non-invasively acquired brain imaging signals in humans. However, the difficulties in optimal application of alert monkey fMRI are multi-faceted, especially at high magnetic fields where the effects of motion and of changes in B-0 are greatly amplified. To overcome these difficulties, strict behavioral controls and elaborate animal-training are needed. Here, we introduce a number of hardware developments, quantify the effect of movements on fMRI data, and present procedures for animal training and scanning for well-controlled and artifact-reduced alert monkey fMRI at high magnetic field. In particular, we describe systems for monitoring jaw and body movements, and for accurately tracking eye movements. A link between body and jaw movement and MRI image artifacts is established, showing that relying on the immobilization of an animal's head is not sufficient for high-quality imaging. Quantitative analysis showed that body and jaw movement events caused large instabilities in fMRI time series. On average, body movement events caused larger instabilities than jaw movement events. Residual baseline brain image position and signal amplitude shifts were observed after the jaw and body movement events ended. Based on these findings, we introduce a novel behavioral paradigm that relies on training the monkeys to stay still during long trials. A corresponding analysis method discards all data that were not obtained during the movement-free periods. The baseline position and amplitude shifts are overcome by motion correction and trial-by-trial signal normalization. The advantages of the presented method over conventional scanning and analysis are demonstrated with data obtained at 7 T. It is anticipated that the techniques presented here will prove useful for alert monkey fMRI at any magnetic field. (c) 2007 Elsevier Inc. All rights reserved.