以光为手段，科学家们发明了一种快速、精确绘制小鼠大脑功能地图的方法。他们在日前在线出版的《自然—方法学》期刊上报告说，与电极绘图法相比，新方法绘制大脑地图的速度比电极绘图法快了多个数级，而且，因为这是一种非侵入性方法，更适合用于长期研究。新方法也将用于技能学习后大脑的重组研究，以及受伤或疾病后神经系统受损害的研究。
大脑动力地图的绘制应该能够鉴别出控制身体特定肌肉的运动的调控区。传统的绘制方法包括刺激置于大脑表面或置于大脑内部的电极，并同时监测肌肉的反应。然而，这些方法都有不利之处，可能会导致某种伤害，费时费力，神经目标的定位也不精确。
Timothy Murphy和同事利用激光激活离子通道，以光为基础绘制了小鼠大脑的运动区域。经基因工程改造后，小鼠的神经细胞在离子通道中被激光照亮，因此不用电极也能看到神经细胞的活动。然后，将麻醉不醒的小鼠直接放在显微镜台上，这样，当激光照射小鼠大脑成百上千的预定区域时，小鼠的动作能够被快速而准确地测定，同时记录的肌肉活动或身体移动所产生的结果产生了可复制的大脑区域地图，这些区域控制了相应的肌肉。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature Methods 15 February 2009 | doi:10.1038/nmeth.1303
Automated light-based mapping of motor cortex by photoactivation of channelrhodopsin-2 transgenic mice
Oliver G S Ayling1,2,5, Thomas C Harrison1,2,5, Jamie D Boyd3,5, Alexander Goroshkov3 & Timothy H Murphy1,2,4
Abstract
Traditionally, mapping the motor cortex requires electrodes to stimulate the brain and define motor output pathways. Although effective, electrode-based methods are labor-intensive, potentially damaging to the cortex and can have off-target effects. As an alternative method of motor mapping, we photostimulated transgenic mice expressing the light-sensitive ion channel channelrhodopsin-2 in predominantly layer-5 output cortical neurons. We report that optical stimulation of these neurons in vivo using a stage scanning laser system resulted in muscle excitation within 10–20 ms, which can be recorded using implanted electromyogram electrodes or by a noninvasive motion sensor. This approach allowed us to make highly reproducible automated maps of the mouse forelimb and hindlimb motor cortex much faster than with previous methods. We anticipate that the approach will facilitate the study of changes in the location and properties of motor maps after skilled training or damage to the nervous system.
1 Kinsmen Laboratory, Department of Psychiatry, 2255 Wesbrook Mall, Vancouver, V6T 1Z3, Canada.
2 Brain Research Center, 2211 Wesbrook Mall, Vancouver, V6T 1Z3, Canada.
3 In Vivo Imaging Centre, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada.
4 Department of Cellular and Physiological Sciences, University of British Columbia, 2255 Wesbrook Mall, Vancouver, V6T 1Z3, Canada.
5 These authors contributed equally to this work.
