Linear Aspects of Changes in Deoxygenated Hemoglobin Concentration and Cytochrome Oxidase Oxidation during Brain Activation
Linear Aspects of Changes in Deoxygenated Hemoglobin Concentration and Cytochrome Oxidase Oxidation during Brain Activation
复制标题
大脑激活过程中脱氧血红蛋白浓度和细胞色素氧化酶氧化的线性变化
作者：
P. Wobst;R. Wenzel;M. Kohl;H. Obrig;A. Villringer
我们使用近红外光谱（NIRS）研究了人类初级和邻近次级视觉皮层对大脑激活的血管和代谢反应。NIRS能够测量脱氧血红蛋白（[脱氧- hb]）的浓度变化（主要是功能磁共振成像（fMRI）中血氧水平依赖性（BOLD）信号的产生），以及氧合血红蛋白（[脱氧- hb]）和红细胞血容量（[total-Hb] =[脱氧- hb] +[脱氧- hb]）的浓度变化，以及细胞色素c氧化酶（[Cyt-Ox]）氧化还原状态的变化，这是细胞氧合的一个假定参数。充分理解刺激参数、神经元活动和血管/代谢参数之间的传递函数对于解释间接神经成像技术（如fMRI）获得的数据非常重要，特别是在事件相关设计研究中。在本研究中，我们测试了血管/代谢对刺激的反应是否可以描述为线性和时不变系统。由于线性是满足尺度和叠加特性的系统的属性，因此作为第一个简单的测试，使用从短时间视觉刺激获得的反应的叠加来预测长时间刺激的反应。我们的研究结果表明，预测[脱氧- hb]和[Cyt-Ox]对刺激持续6至24秒的反应是令人满意的，而[脱氧- hb]和[总- hb]的预测是不充分的。第二步，将假设的脉冲响应函数与刺激函数的计算卷积函数与实测的[deoxy-Hb]和[Cyt-Ox]曲线拟合，得到振幅、时延和时间常数参数。我们表明，在线性传递特性的假设下，细胞和血管对视觉刺激的氧合反应在6到24秒的刺激持续时间内是很好的预测。该模型不适用于主要影响[氧-血红蛋白]反应的红细胞体积变化。无创近红外光谱被证明是一种更适合的方法来获得更直接的信息神经元活动相关的大脑参数的变化，这些变化部分反映在BOLD信号中，但尚未完全了解。
We used near infrared spectroscopy (NIRS) to investigate the vascular and metabolic response to brain activation in human primary and adjacent secondary visual cortex. NIRS is able to measure concentration changes in deoxygenated hemoglobin ([deoxy-Hb]) (which mainly contribute to the blood oxygenation level-dependent (BOLD) signal in functional magnetic resonance imaging (fMRI)) as well as concentration changes of oxygenated hemoglobin ([oxy-Hb]) and corpuscular blood volume ([total-Hb] = [oxy-Hb] + [deoxy-Hb]) and changes in the redox status of the cytochrome c oxidase ([Cyt-Ox]), a putative parameter for cellular oxygenation. A sound understanding of the transfer functions between stimulus parameters, neuronal activity, and vascular/metabolic parameters is important for interpretation of data acquired with indirect neuroimaging techniques like fMRI, especially in event-related design studies. In the present study we tested whether the vascular/metabolic response to stimulation can be described as a linear and time invariant system. Since linearity is a property attributed to systems that satisfy the scaling and superposition properties, as a first simple test, superposition of the responses obtained from short duration visual stimuli was used to predict the responses of longer duration stimuli. Our results showed that the predictions of [deoxy-Hb] and [Cyt-Ox] responses to stimuli of 6- to 24-s duration were satisfactory whereas predictions of [oxy-Hb] and [total-Hb] were insufficient. In a second step, a calculated convolution function of an assumed impulse response function and the stimulus function was fitted with the measured [deoxy-Hb] and [Cyt-Ox] curves to obtain amplitude, time delay, and time constant parameters. We show that predictions of cellular and vascular oxygenation responses to visual stimulation are good for 6- to 24-s stimuli duration under the assumption of a linear transfer characteristic. This model is not valid for corpuscular volume changes which affect mainly the [oxy-Hb] response. Noninvasive NIRS is shown to be a suitable method to get more direct information about neuronal-activity-associated changes in cerebral parameters which are partly reflected in BOLD signal but are not fully understood yet.
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影响因子：
2.5
作者：
SCLAR, G;OHZAWA, I;FREEMAN, RD
通讯作者：
FREEMAN, RD
颅内近红外光学扫描的可行性。
影响因子：
3.7
作者：
Gratton,G;Maier,JS;Fabiani,M;Mantulin,WW;Gratton,E
通讯作者：
Gratton,E
影响因子：
2.5
作者：
OHZAWA, I;SCLAR, G;FREEMAN, RD
通讯作者：
FREEMAN, RD
DOI：
10.1073/pnas.89.13.5951
发表时间：
1992-07-01
影响因子：
11.1
作者：
OGAWA, S;TANK, DW;UGURBIL, K
通讯作者：
UGURBIL, K
DOI：
10.1073/pnas.90.8.3770
发表时间：
1993-04-15
影响因子：
11.1
作者：
CHANCE, B;ZHUANG, Z;LIPTON, L
通讯作者：
LIPTON, L