活体小鼠后顶叶皮质神经元双光子成像与空间定向机制

Neural mechanism of the spatial orienting in posterior parietal cortex of mice in vivo:two-photon brain imaging study

目的:结合双光子显微镜和Morris水迷宫探讨右侧顶叶皮质在空间认知功能中的作用机制。方法:选用C57BL/6J小鼠18只,随机分为正常对照组和右侧顶叶损毁组,用直流电损害小鼠的后顶叶皮质,正常对照组未做任何处理。在双光子显微镜下观测小鼠活体内右侧顶叶皮质神经元活动,Morris水迷宫评价小鼠的空间认知功能。结果:在双光子显微镜下,损毁组小鼠较正常组右侧顶叶皮质功能神经细胞明显减少,神经元跨膜电位明显减弱。在水迷宫空间任务中,损毁组小鼠空间学习能力及空间探索功能也均明显减弱。结论:双光子显微镜可在活体动物直接观察神经元活动;正常右侧后顶叶功能神经元活动是空间定向认知的关键。

Objective： To demonstrate the crucial role of right posterior parietal cortex in spatial orienting using two-pho- ton microscope detecting cortical neuronal activity and Morris water maze testing visuospatial function of mice. Method： Eighteen C57BL/6J mice were randomly divided into two groups as damaged group which received electrolytic lesion in right posterior parietal cortex and normal control group which received no operation. Mor- ris water maze was used to test visuospatial orienting function. And then, depose the mice under two-photon to observe and record. Result： Under the two-photon calcium imaging, in right posterior parietal cortex of damaged mice the recorded neurons significantly decreased compared with normal control group. Moreover, in right posterior parietal cortex the number of both neuron cell and neurogliocyte decreased significantly. The transmembrane potentials of neu- ron roduced significontly. During Morris water maze test, the damaged mice showed significant deficits in spa- tial learning ability and spatial explore orienting function compared with normal control group. Conclusion： Two-photon microscope can detect online neuronal activity, with high temporal and spatial resolu- tion. Normal right posterior parietal cortex plays a crucial role in spatial orienting cognition. Author＇s address Department of Rehabilitation Medicine, the First Affiliated Hospital of Sun Yat-Sen Universi- ty, Guangzhou, 510080