Line scanning fMRI reveals earlier onset of optogenetically evoked BOLD response in rat somatosensory cortex as compared to sensory stimulation
Line scanning fMRI reveals earlier onset of optogenetically evoked BOLD response in rat somatosensory cortex as compared to sensory stimulation
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DOI：
10.1016/j.neuroimage.2016.12.059
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发表时间：
2018-01-01
期刊：
影响因子：
5.7
通讯作者：
Faber, Cornelius
中科院分区：
文献类型：
--
作者：
Albers, Franziska;Schmid, Florian;Faber, Cornelius
大脑中的光遗传学控制和功能磁共振成像读出的组合越来越多地用于评估神经元网络和潜在的信号处理。然而，光遗传学激活或抑制如何精确地再现正常的生理输入尚未完全解开。为了评估血流动力学反应的时间动态的细节，啮齿动物fMRI的时间分辨率往往是不够的。人类功能磁共振成像的最新进展，使用更快的采集方案，不能很容易地翻译到小动物，由于尺寸较小，快速的生理运动，和更高的灵敏度，文物。在这里，我们采用了一维线扫描采集与50毫秒的时间分辨率在大鼠体感皮层。我们观察到，光遗传学激活再现了感觉刺激时的血液动力学反应，但显示出160至340 ms的反应提前发作。这种差异是由所有视蛋白表达和照明皮质层的直接激活来解释的，而对感觉刺激的血流动力学反应在皮质层之间的皮质内传输期间被延迟。我们的研究结果证实，光遗传学激活是一个有效的生理神经元输入模型，只有几百毫秒的时间行为的差异，可以解决在啮齿动物功能磁共振成像。
The combination of optogenetic control and fMRI readout in the brain is increasingly used to assess neuronal networks and underlying signal processing. However, how exactly optogenetic activation or inhibition reproduces normal physiological input has not been fully unraveled. To assess details of temporal dynamics of the hemodynamic response, temporal resolution in rodent fMRI is often not sufficient. Recent advances in human fMRI using faster acquisition schemes cannot be easily translated to small animals due to smaller dimensions, fast physiological motion, and higher sensitivity to artefacts. Here, we applied a one dimensional line scanning acquisition with 50 ms temporal resolution in rat somatosensory cortex. We observed that optogenetic activation reproduces the hemodynamic response upon sensory stimulation, but shows a 160 to 340 ms earlier onset of the response. This difference is explained by direct activation of all opsin-expressing and illuminated cortical layers, while hemodynamic response to sensory stimulation is delayed during intracortical transmission between cortical layers. Our results confirm that optogenetic activation is a valid model for physiological neuronal input, and that differences in temporal behavior of only a few hundred milliseconds can be resolved in rodent fMRI.