每天的光/暗周期影响动物的学习,记忆,和认知。暴露于不足的日光照明会对情绪和认知产生负面影响,导致以抑郁为特征的季节性情感障碍,焦虑,低动机,和昼夜动物的认知障碍。然而,这如何影响记忆,学习,夜间啮齿动物的认知在很大程度上是未知的。这里,我们研究了白天光照对记忆的影响,学习,认知,和海马中mRNA水平的表达,丘脑,和皮质,高阶学习中心。进行了两个实验。在实验一,将大鼠暴露于12L:12D(12小时光照和12小时黑暗),白天光照照度为10、100或1000lx。30天后,各种行为测试(新颖的物体识别测试,孔板测试,高架加迷宫测试,径向臂迷宫,和被动回避测试)进行。在实验2中,大鼠从出生开始在恒定的亮光(250lx;LL)或每日明暗循环(12L:12D)下饲养。四个月后,行为测试(新颖的物体识别测试,孔板测试,高架加迷宫测试,径向臂迷宫,被动回避测试,莫里斯水迷宫,和Y迷宫测试)进行。实验结束时,对大鼠进行采样,脑源性神经营养因子(Bdnf)的mRNA表达,酪氨酸激酶(Trk),microRNA132(miR132),神经颗粒素(Ng),生长相关蛋白43(Gap-43),cAMP反应元件结合蛋白(Crebp),糖原合成酶激酶-3β(Gsk3β),在海马中测量肿瘤坏死因子-α(Tnf-α),皮质,和单个大鼠的丘脑。我们的结果表明,暴露于明亮的日光(100和1000lx;实验1)或恒定的光(实验2)会损害记忆,学习,和认知。在下丘脑中也观察到这些mRNA的抑制表达水平,皮质,还有丘脑.这些结果表明,光线对不同动物群体的影响不同。
The daily light/dark cycle affects animals\' learning, memory, and cognition. Exposure to insufficient daylight
illumination negatively impacts emotion and cognition, leading to seasonal affective disorder characterized by depression, anxiety, low motivation, and cognitive impairment in diurnal animals. However, how this affects memory, learning, and cognition in nocturnal rodents is largely unknown. Here, we studied the effect of daytime light illuminance on memory, learning, cognition, and expression of mRNA levels in the hippocampus, thalamus, and cortex, the higher-order learning centers. Two experiments were performed. In experiment one, rats were exposed to 12 L:12D (12 h light and 12 h dark) with a 10, 100, or 1000 lx daytime light illuminance. After 30 days, various behavioral tests (novel object recognition test, hole board test, elevated plus maze test, radial arm maze, and passive avoidance test) were performed. In experiment 2, rats since birth were raised either under constant bright light (250 lx; LL) or a daily light-dark cycle (12 L:12D). After four months, behavioral tests (novel object recognition test, hole board test, elevated plus maze test, radial arm maze, passive avoidance test, Morris water maze, and Y-maze tests) were performed. At the end of experiments, rats were sampled, and mRNA expression of Brain-Derived Neurotrophic Factor (Bdnf), Tyrosine kinase (Trk), microRNA132 (miR132), Neurogranin (Ng), Growth Associated Protein 43 (Gap-43), cAMP Response Element-Binding Protein (Crebp), Glycogen synthase kinase-3β (Gsk3β), and Tumour necrosis factor-α (Tnf-α) were measured in the hippocampus, cortex, and thalamus of individual rats. Our results show that exposure to bright daylight (100 and 1000 lx; experiment 1) or constant light (experiment 2) compromises memory, learning, and cognition. Suppressed expression levels of these mRNA were also observed in the hypothalamus, cortex, and thalamus. These results suggest that light affects differently to different groups of animals.