Department of Biomedical Engineering and Computational Science, School of Science and Technology, Aalto University, P.O. Box 12200, 00076, Aalto, Finland.
Exp Brain Res. 2010 May;202(3):561-70. doi: 10.1007/s00221-010-2159-9. Epub 2010 Jan 20.
The interaction of brain hemodynamics and neuronal activity has been intensively studied in recent years to yield better understanding of brain function. We investigated the relationship between visual-evoked hemodynamic responses (HDRs), measured with near-infrared spectroscopy (NIRS), and neuronal activity in humans, approximated with the stimulus train duration or with visual-evoked potentials (VEPs). Concentration changes of oxyhemoglobin (HbO(2)) and deoxyhemoglobin (HbR) in tissue and VEPs were recorded simultaneously over the occipital lobe of ten healthy subjects to 3, 6, and 12 s pattern-reversing checkerboard stimulus trains having a reversal frequency of 2 Hz. We found that the area-under-the-curves (Sigma) of HbO(2) and HbR were linearly correlated with the stimulus train duration and with the SigmaVEP summed over the 3, 6, and 12 s stimulus train durations. The correlation was stronger between the SigmaHbO(2) or the SigmaHbR and the SigmaVEP than between the SigmaHbO(2) or the SigmaHbR and the stimulus train duration. The SigmaVEPs explained 55% of the SigmaHbO(2) and 74% of the SigmaHbR variance, whereas the stimulus train duration explained only 45% of the SigmaHbO(2) and 51% of the SigmaHbR variance. We used Sigma of the NIRS responses and VEPs because we wanted to incorporate all possible processes (e.g., attention, habituation, etc.) affecting the responses. The results indicate that the relationship between brain HDRs and VEPs is approximately linear for 3-12 s long stimulus trains consisting of checkerboard patterns reversing at 2 Hz. To interpret hemodynamic responses, the measurement of evoked potentials is beneficial compared to the use of indirect parameters such as the stimulus duration. In addition, interindividual differences in the HbO(2) and HbR responses may be partly explained with differences in the VEPs.
近年来，人们深入研究了大脑血液动力学和神经元活动的相互作用，以更好地理解大脑功能。我们研究了人类视觉诱发电血动力学反应（HDR）与神经元活动之间的关系，用近红外光谱（NIRS）测量 HDR，用刺激序列时长或视觉诱发电位（VEP）近似模拟神经元活动。我们在 10 位健康被试的枕叶上同时记录组织中氧合血红蛋白（HbO2）和脱氧血红蛋白（HbR）浓度的变化以及 3、6 和 12 s 棋盘格模式反转刺激序列的 VEP，刺激序列的反转频率为 2 Hz。我们发现，HbO2 和 HbR 的曲线下面积（Sigma）与刺激序列时长以及 SigmaVEP 呈线性相关，SigmaVEP 是 3、6 和 12 s 刺激序列时长的总和。与刺激序列时长相比，SigmaHbO2 或 SigmaHbR 与 SigmaVEP 的相关性更强。SigmaVEP 解释了 SigmaHbO2 变化的 55%和 SigmaHbR 变化的 74%，而刺激序列时长仅解释了 SigmaHbO2 变化的 45%和 SigmaHbR 变化的 51%。我们使用 NIRS 响应和 VEP 的 Sigma，是因为我们希望将影响响应的所有可能过程（例如注意力、习惯化等）纳入其中。结果表明，对于由 2 Hz 反转的棋盘格图案组成的 3-12 s 长刺激序列，大脑 HDR 和 VEP 之间的关系近似线性。为了解释血液动力学响应，与使用间接参数（如刺激时长）相比，测量诱发电位更有益。此外，HbO2 和 HbR 响应的个体间差异可以部分用 VEP 的差异来解释。
