Laboratoire Imagerie et Modélisation en Neurobiologie et Cancérologie, UMR Université Paris Sud, CNRS, Campus d'Orsay Bat, France.
Cell Mol Life Sci. 2011 Aug;68(16):2689-709. doi: 10.1007/s00018-011-0708-4. Epub 2011 May 17.
The brain transforms clues from the external world, the sensory stimuli, into activities in neuroglial networks. These circuits are activated in specialized sensory cortices where specific functional modules are responsible for the spatiotemporal coding of the stimulus. A major challenge in the neuroscience field has been to image the spatial distribution and follow the temporal dynamics of the activation of such large populations in vivo. Functional imaging techniques developed in the last 30 years have enabled researchers to solve this critical issue, and are reviewed here. These techniques utilize sources of contrast of radioisotopic, magnetic and optical origins and exploit two major families of signals to image sensory activity: the first class uses sources linked to cellular energy metabolism and hemodynamics, while the second involves exogenous indicators of neuronal activity. The whole panel of imaging techniques has fostered the functional exploration of the olfactory bulb which is one of the most studied sensory structures. We summarize the major results obtained using these techniques that describe the spatial and temporal activity patterns in the olfactory glomeruli, the first relay of olfactory information processing in the main olfactory bulb. We conclude this review by describing promising technical developments in optical imaging and future directions in the study of olfactory spatiotemporal coding.
大脑将来自外部世界的线索，即感觉刺激，转化为神经胶质网络的活动。这些回路在专门的感觉皮层中被激活，特定的功能模块负责刺激的时空编码。神经科学领域的一个主要挑战一直是在体内对如此大的群体的激活进行空间分布和时间动态成像。在过去 30 年中开发的功能成像技术使研究人员能够解决这个关键问题，本文对这些技术进行了综述。这些技术利用放射性同位素、磁性和光学起源的对比度源，并利用两类主要的信号来对感觉活动进行成像：第一类使用与细胞能量代谢和血液动力学相关的源，而第二类则涉及神经元活动的外源性指示剂。整个成像技术面板促进了对嗅球的功能探索，嗅球是研究最多的感觉结构之一。我们总结了使用这些技术获得的主要结果，这些结果描述了在主要嗅球中嗅觉信息处理的第一级中继——嗅球小球中的空间和时间活动模式。我们通过描述光学成像中的有前途的技术发展和嗅觉时空编码研究的未来方向来结束这篇综述。
