Max-Planck Institute for Biological Cybernetics, Tübingen, Germany.
Magn Reson Imaging. 2010 Oct;28(8):1095-103. doi: 10.1016/j.mri.2009.12.016. Epub 2010 Jan 21.
Functional magnetic resonance imaging (fMRI) based on the so-called blood oxygen level-dependent (BOLD) contrast is a powerful tool for studying brain function not only locally but also on the large scale. Most studies assume a simple relationship between neural and BOLD activity, in spite of the fact that it is important to elucidate how the "when" and "what" components of neural activity are correlated to the "where" of fMRI data. Here we conducted simultaneous recordings of neural and BOLD signal fluctuations in primary visual (V1) cortex of anesthetized monkeys. We explored the neurovascular relationship during periods of spontaneous activity by using temporal kernel canonical correlation analysis (tkCCA). tkCCA is a multivariate method that can take into account any features in the signals that univariate analysis cannot. The method detects filters in voxel space (for fMRI data) and in frequency-time space (for neural data) that maximize the neurovascular correlation without any assumption of a hemodynamic response function (HRF). Our results showed a positive neurovascular coupling with a lag of 4-5 s and a larger contribution from local field potentials (LFPs) in the γ range than from low-frequency LFPs or spiking activity. The method also detected a higher correlation around the recording site in the concurrent spatial map, even though the pattern covered most of the occipital part of V1. These results are consistent with those of previous studies and represent the first multivariate analysis of intracranial electrophysiology and high-resolution fMRI.
基于所谓血氧水平依赖（BOLD）对比的功能磁共振成像（fMRI）是研究大脑功能的强大工具，不仅可以在局部范围内进行，还可以在大规模范围内进行。尽管阐明神经活动的“何时”和“什么”成分与 fMRI 数据的“何处”相关非常重要，但大多数研究都假设神经和 BOLD 活动之间存在简单的关系。在这里，我们在麻醉猴子的初级视觉（V1）皮层中同时记录了神经和 BOLD 信号波动。我们通过使用时间核典型相关分析（tkCCA）来探索自发活动期间的神经血管关系。tkCCA 是一种多变量方法，可以考虑单变量分析无法考虑的信号中的任何特征。该方法在体素空间（对于 fMRI 数据）和频时空间（对于神经数据）中检测到滤波器，这些滤波器可在不假设血流动力学响应函数（HRF）的情况下最大化神经血管相关性。我们的结果显示，正神经血管耦合具有 4-5 秒的滞后，并且γ频带的局部场电位（LFPs）比低频 LFPs 或尖峰活动的贡献更大。该方法还在同时的空间图中在记录部位周围检测到更高的相关性，即使该模式覆盖了 V1 的大部分枕叶部分。这些结果与之前的研究结果一致，代表了颅内电生理学和高分辨率 fMRI 的首次多变量分析。
