Neurophysiological investigation of the basis of the fMRI signal
Neurophysiological investigation of the basis of the fMRI signal
复制标题
DOI：
10.1038/35084005
复制
发表时间：
2001-07-12
期刊：
影响因子：
64.8
通讯作者：
Oeltermann, A
中科院分区：
文献类型：
--
作者：
Logothetis, NK;Pauls, J;Oeltermann, A
功能磁共振成像（fMRI）广泛用于研究人脑的运作组织，但测量的 fMRI 信号与潜在神经活动之间的确切关系尚不清楚。在这里，我们展示了神经信号和功能磁共振成像反应的同步皮质内记录。我们将局部场电位 (LFP)、单单元和多单元尖峰活动与猴子视觉皮层的高度时空分辨血氧水平依赖性 (BOLD) fMRI 响应进行了比较。在 LFP 中观察到最大幅度的变化，其在以瞬时响应为特征的记录位点是唯一与血液动力学响应显着相关的信号。逐项试验的线性系统分析表明，神经血管系统的脉冲响应是动物特异性和部位特异性的，并且 LFP 比多单元响应能更好地估计 BOLD 响应。这些发现表明，BOLD 对比机制反映了给定区域的输入和皮质内处理，而不是其尖峰输出。
Functional magnetic resonance imaging (fMRI) is widely used to study the operational organization of the human brain, but the exact relationship between the measured fMRI signal and the underlying neural activity is unclear. Here we present simultaneous intracortical recordings of neural signals and fMRI responses. We compared local field potentials (LFPs), single- and multi-unit spiking activity with highly spatio-temporally resolved blood-oxygen-level-dependent (BOLD) fMRI responses from the visual cortex of monkeys. The largest magnitude changes were observed in LFPs, which at recording sites characterized by transient responses were the only signal that significantly correlated with the haemodynamic response. Linear systems analysis on a trial-by-trial basis showed that the impulse response of the neurovascular system is both animal- and site-specific, and that LFPs yield a better estimate of BOLD responses than the multi-unit responses. These findings suggest that the BOLD contrast mechanism reflects the input and intracortical processing of a given area rather than its spiking output.