COGNITION-ACTIVATED LOW-FREQUENCY MODULATION OF LIGHT-ABSORPTION IN HUMAN BRAIN
COGNITION-ACTIVATED LOW-FREQUENCY MODULATION OF LIGHT-ABSORPTION IN HUMAN BRAIN
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DOI：
10.1073/pnas.90.8.3770
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发表时间：
1993-04-15
影响因子：
11.1
通讯作者：
LIPTON, L
中科院分区：
文献类型：
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作者：
CHANCE, B;ZHUANG, Z;LIPTON, L
动物模型研究表明，暴露的动物大脑对视觉刺激的光吸收变化。在这里，我们报告了红光吸收变化的观察结果，这可归因于人类大脑额叶区通过认知过程刺激引起的血液浓度的重复变化。通过傅里叶变换分析，这些反应被观察到为低频复发的变化，并归因于认知功能中脑组织代谢率增加所刺激的血浓度变化。将一种简单的便携式双波长分光光度计无创地附着在人的前额上，测量额叶区域脑血浓度变化引起的吸光度波动的低频和功率谱。这些反应与解决视觉类比问题的大脑活动有关，这需要额叶区域的联想功能。测试休息傅里叶变换的减法将动脉脉冲频率贡献最小化，并确定特定频率-例如，在9个人的28次测试中，有24次（85%）为0.8,1.6,1.8 Hz。没有引起大脑活动增加的测试（休息-休息）显示出微小的差异。结论是，在人类受试者中，使用电位光学装置在0- 3hz区域进行简化的认知功能测试，并通过时间分辨光谱对局部组织体积进行更宽的波段记录进行修改，可以检测到与血液浓度增加相关的低频脑活动复发。
Animal model studies indicate light-absorption changes of the exposed animal brain in response to visual stimulation. Here we report observations of red-light absorbancy changes, attributable to repetitive blood concentration changes in response to stimulation in the human brain frontal region by a cognitive process. These responses are observed as low-frequency recurrence of changes by Fourier transform analysis and are attributed to blood concentration change stimulated by the increased metabolic rate of brain tissue in cognitive function. A simple, portable dual wavelength spectrophotometer was attached noninvasively to the human forehead to measure the low frequency and power spectra of fluctuations of absorbancies attributed to variations of brain blood concentration in the frontal region. The responses are associated with brain activity in responses to problem solving of analogies presented visually that require an associative function in the frontal region. The method of subtraction of test - rest Fourier transforms minimizes the arterial pulse frequency contributions and identifies specific frequencies - for example, 0.8, 1.6, 1.8 Hz in 24 of 28 tests of nine individuals (85%). Tests in which no increased brain activity was elicited (rest - rest) showed small differences. It is concluded that low-frequency recurrences of brain activity linked to blood concentration increases can be detected in human subjects with an optical device of potentiality for simplified tests of cognitive function in the 0- to 3-Hz region and with modifications for wider band recordings in localized tissue volumes by time-resolved spectroscopy.