Spatial Relationship between Flavoprotein Fluorescence and the Hemodynamic Response in the Primary Visual Cortex of Alert Macaque Monkeys.
Spatial Relationship between Flavoprotein Fluorescence and the Hemodynamic Response in the Primary Visual Cortex of Alert Macaque Monkeys.
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DOI：
10.3389/fnene.2010.00006
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发表时间：
2010-01-01
期刊：
影响因子：
--
通讯作者：
Das, Aniruddha
中科院分区：
文献类型：
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作者：
Sirotin, Yevgeniy B;Das, Aniruddha
黄素蛋白荧光成像(FFI)是一种新的内在光学信号，由于其与局部代谢的关系比更常用的血流动力学信号更接近局部代谢，因此在神经科学研究中正逐渐成为一种有价值的成像工具。我们开发了一种在警觉猴子的初级视觉皮质(V1)进行FFI成像的技术。由于神经血管偶联的性质，血流动力学信号被认为是传播到代谢活动场所之外的。为了确定FFI信号是否可以更集中地衡量警觉动物的皮质活动，我们比较了FFI信号和血流动力学点扩散(即对最小视觉刺激的反应)以及执行简单注视任务的猕猴V1上的功能映射信号。FFI的反应是双相的，早期和局灶性的荧光增强，随后是延迟的和空间上更宽的荧光下降。正如预期的那样，早期的荧光增强，表明局部氧化代谢增强，比同时观察到的血流动力学反应要窄一些。然而，后来的FFI下降比血流动力学反应更广泛，在视觉刺激停止之前就开始了，这表明荧光信号的两个阶段背后的机制不同。FFI标测信号没有血管伪影，在幅度上与血流动力学标测信号相当。这些结果表明，与警觉动物的血流动力学反应相比，FFI反应可能是更局部和更直接的皮质代谢指标。
Flavoprotein fluorescence imaging (FFI) is a novel intrinsic optical signal that is steadily gaining ground as a valuable imaging tool in neuroscience research due to its closer relationship with local metabolism relative to the more commonly used hemodynamic signals. We have developed a technique for FFI imaging in the primary visual cortex (V1) of alert monkeys. Due to the nature of neurovascular coupling, hemodynamic signals are known to spread beyond the locus of metabolic activity. To determine whether FFI signals could provide a more focal measure of cortical activity in alert animals, we compared FFI and hemodynamic point spreads (i.e. responses to a minimal visual stimulus) and functional mapping signals over V1 in macaques performing simple fixation tasks. FFI responses were biphasic, with an early and focal fluorescence increase followed by a delayed and spatially broader fluorescence decrease. As expected, the early fluorescence increase, indicating increased local oxidative metabolism, was somewhat narrower than the simultaneously observed hemodynamic response. However, the later FFI decrease was broader than the hemodynamic response and started prior to the cessation of visual stimulation suggesting different mechanisms underlying the two phases of the fluorescence signal. FFI mapping signals were free of vascular artifacts and comparable in amplitude to hemodynamic mapping signals. These results indicate that the FFI response may be a more local and direct indicator of cortical metabolism than the hemodynamic response in alert animals.