高时空分辨的脑功能光学成像研究进展

Progress on Optical Imaging of Functional Brain With High Temporal and Spatial Resolution

脑功能成像技术对深入分析脑的信息加工过程,揭示脑的高级功能至关重要,是目前国际研究热点,已经在神经科学研究和神经系统疾病的临床诊断方面取得了很大的进展.已有脑功能成像技术如:功能磁共振成像(fMRI)、正电子断层成像(PET)、脑电图(EEG)、脑磁图(MEG)等等,虽然已被成功用于脑功能研究,但是目前这些方法也存在着时间或空间分辨率不够的局限.比较而言,光学成像方法表现出其独特魅力.激光散斑衬比成像和内源信号光学成像由于能提供空间取样、时间分辨率及空间分辨率三者的最佳组合和不需加入外源性标记物等特点,与其他脑功能成像技术相比其优势可能更为突出.具有较高的时间和空间分辨率的这两种脑功能光学成像技术及其应用都取得了重大发展,成为研究脑皮层功能构筑和脑病理生理的有力工具.但是目前这两种成像方法也面临着一些挑战.

Techniques for functional brain imaging are critical to analyze the information processing of brain and to reveal the advanced functions in brain. These techniques are the hot topics of international research. Great success has been obtained with neuroimaging techniques in the fields of neuroscience research and clinical diagnosis. Existing brain functional imaging such as magnetic resonance imaging （fMRI）, positron emission tomography （PET）, electroencephalogram （EEG）, magnetoencephalography （MEG） and so on, have been successfully used to study brain function. However, these methods have some limitations unavoidably in the temporal or spatial resolution at present. Comparatively, the optical imaging technologies of brain function show their unique charms. Laser speckle imaging （LSI） and intrinsic optical signals imaging （IOSI） stand out because they offer a superior combination of spatial sampling, spatial resolution and temporal resolution; on the other hand, they have no need to use exogenous contrast agents. Great developments also have been obtained in both techniques and applications of brain optical imaging, and they have become powerful tools for in vivo studying functional architecture and pathophysiology in cerebral cortex by monitoring hemodynamics. However, the two optical imaging techniques are confronted with some challenges.