高糖饮食对青年小鼠初级视觉皮层的功能损伤及其机制

Functional Impairment and Mechanism of The Primary Visual Cortex of Young Mice With High-sugar Diet

目的诸多研究证实高糖饮食会对视觉功能造成损伤,但是目前关于高糖饮食对视觉功能影响的研究主要聚焦于视觉通路前端,集中在眼球系统和视神经节部分,对于视觉通路的后端如中枢皮层还未有过相关报道。为了更全面地了解高糖饮食对视觉功能的影响,本文补充高糖饮食对视觉中枢皮层影响的研究。方法本研究利用GO/NO-GO方位辨别任务的行为学范式、在体多通道电生理技术探究了高糖饮食对青年小鼠初级视觉皮层的影响。结果行为学结果表明,经历了2个月高糖喂养的青年小鼠,方位辨别能力下降。通过电生理技术分析初级视觉皮层(V1)单个神经元的反应特性,发现高糖饮食小鼠初级视觉皮层单个神经元的方位调谐能力下降,神经元的反应变异性增加、信噪比明显降低。神经元噪音相关性分析结果表明,高糖饮食组小鼠初级视觉皮层的噪音相关性表现出明显的上调。进一步分析群体水平上信噪比和反应变异性的变化,结果表明群体水平上信噪比明显下降而反应变异性明显上升。结论高糖饮食通过影响初级视觉皮层单个神经元的感受野特征以及群体神经元的信息处理能力,损伤了青年小鼠的方位辨别能力。

Objective Many studies have shown that a high-sugar diet can do a lot of harm to the health of teenagers.As one of the important windows for human to perceive the world,the visual system plays an important role in teenagers’perception ability.Many studies have confirmed that high-sugar diet can damage visual function,but the current research on the effects of high-sugar diet on visual function mainly focuses on the front of the visual pathway,focusing on the eye system and the optic ganglion,the posterior of the visual pathway,such as the visual central cortex,has not been reported.In order to understand the effect of high sugar diet on visual function,the effect of high sugar diet on central cortex was studied.Methods In this study,we used the behavioral paradigm of GO/NO-GO orientation discrimination task and in vivo multi-channel electrophysiological techniques to explore the effects of high-sugar diet on the primary visual cortex of young mice.Results Behavioral results showed that young mice that had undergone two months of high-sugar diet had a reduced ability to distinguish orientation.The response characteristics of single neurons in the primary visual cortex(V1)were analyzed by electrophysiological techniques.It was found that the ability of orientation tuning of single neurons in the primary visual cortex decreased in mice fed with high-sugar diet,the response variability of neurons increased and the signal-to-noise ratio(SNR)decreased significantly.We further analyzed the changes of SNR and response variability at population level.The results showed that SNR decreased significantly and response variability increased significantly at population level.The results of neuron correlation analysis showed that the noise correlation of primary visual cortex in the high-sugar diet group was significantly up-regulated.Conclusion These results suggest that a high-sugar diet impairs the ability of young mice to discriminate orientation by affecting the receptive field characteristics of individual neurons in the primary visual cortex,as well as the information processing capacity of neuronal populations.