Central Research Laboratory, Hitachi, Ltd., 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo 185-8601, Japan.
J Biomed Opt. 2012 Oct;17(10):107001. doi: 10.1117/1.JBO.17.10.107001.
The correlation between neuronal activity and cortical hemodynamics, namely, neurovascular coupling (NVC), is important to shed light on the mechanism of a variety of brain functions or neuronal diseases. NVC can be studied by simultaneously measuring neuronal activity and cortical hemodynamics. Consequently, noninvasive measurements of the NVC have been widely studied using both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). However, electromagnetic interference between EEG and fMRI is still a major problem. On the other hand, near-infrared spectroscopy (NIRS) is another promising tool for detecting cortical hemodynamics because it can be combined with EEG or magnetoencephalography (MEG) without any electromagnetic interference. Accordingly, in the present study, a simultaneous measurement system-combining an unshielded MEG using a two-dimensional gradiometer based on a low-Tc superconducting quantum interference device (SQUID) and an NIRS using nonmagnetic thin probes-was developed. This combined system was used to simultaneously measure both an auditory-evoked magnetic field and blood flow change in the auditory cortex. It was experimentally demonstrated that the combined unshielded MEG/NIRS system can simultaneously measure neuronal activity and cortical hemodynamics.
神经元活动与皮质血液动力学之间的相关性，即神经血管耦合（NVC），对于揭示各种脑功能或神经元疾病的机制非常重要。可以通过同时测量神经元活动和皮质血液动力学来研究 NVC。因此，已经广泛使用脑电图（EEG）和功能磁共振成像（fMRI）来研究 NVC 的非侵入性测量。然而，EEG 和 fMRI 之间的电磁干扰仍然是一个主要问题。另一方面，近红外光谱（NIRS）是检测皮质血液动力学的另一种有前途的工具，因为它可以与 EEG 或脑磁图（MEG）结合使用，而不会产生任何电磁干扰。因此，在本研究中，开发了一种结合了基于低温超导量子干涉装置（SQUID）的二维梯度计的无屏蔽 MEG 和使用非磁性薄探头的 NIRS 的同时测量系统。该组合系统用于同时测量听觉诱发电磁场和听觉皮层中的血流变化。实验证明，组合的无屏蔽 MEG/NIRS 系统可以同时测量神经元活动和皮质血液动力学。
