Molecular determinants of brain size and cognitive performance

高等生物体依靠它们的认知能力来争夺食物、领土和配偶等资源：因此，大脑功能与健康直接相关。至少在人类中，大脑大小和认知表现之间似乎存在联系，因为小头畸形通常伴随着认知障碍。大脑的发育对环境很敏感，生命早期的压力会对大脑的发育、功能和认知产生负面影响。在这里，我们的目标是破译决定大脑大小的转录组和共表达网络签名。切尔诺贝利(乌克兰)核事故的持续影响为我们提供了量化环境应激(暴露于电离辐射)与野生脊椎动物种群脑体积缩小之间的联系的机会。切尔诺贝利前核电站周围地区放射性核素污染的马赛克使得可以在环境条件相似但污染程度不同的地区进行重复实验采样。使用啮齿动物黄鼠和斑腿鼠，我们将对土壤放射性核素污染水平不同的地区个体的额叶皮质、海马体、杏仁核和运动皮质的转录进行测序，以确定基因表达和共表达网络的差异(来自高、中、低污染地区的10只雄性和雌性；总共n=480个转录体)。被用于转录组研究的同一批人将进行标准的行为测试，他们的基础代谢率将被测量，大脑质量将被记录，以将转录组模式与能量成本、大脑大小和认知表现联系起来。研究两个物种将使我们能够确定大脑大小和认知背后的共同分子决定因素。此外，考虑到未来核灾难的风险越来越大，我们的目标是为此类灾难对生物体的健康后果提供重要的内部信息，作为人类生物学的相关模型。

Higher organism rely on their cognitive abilities to compete for resources such as food, territories and mates: brain function is thus directly linked with fitness. There seems to be a link between brain size and cognitive performance at least in humans, since microcephaly usually goes along with cognitive disabilities. Development of the brain is sensitive to the environment, with stress during early life negatively affecting brain development, functions and cognition. Here we aim to decipher the transcriptome and co-expression network signatures that determine brain size. Persistent effects of the nuclear accident in Chernobyl (Ukraine) provide us with the opportunity to quantify the association between environmental stress (exposure to ionizing radiation) and reduced brain size in wild vertebrate populations. The mosaic of radionuclide contamination in the area surrounding the former nuclear power plant at Chernobyl permits repeated experimental sampling within an area of similar environmental conditions but with different levels of contamination. Using the rodents Apodemus flavicolis and Myodes glareolus, we will sequence the transcriptomes of the frontal cortex, hippocampus, amygdala, and motor cortex from individuals inhabiting areas with contrasting levels of soil radionuclide contamination to determine differences in gene expression and co-expression networks (10 males and females from high, intermediate and low contamination regions; n = 480 transcriptomes in total). The very same individuals that will be used for the transcriptome study will perform standard behavioral tests, their basal metabolic rate will be measures and brain mass will be recorded, to link the transcriptome patterns to energetic costs, brain size and cognitive performance. Studying two species will allow us to determine the common molecular determinants underlying brain size and cognition. Further, considering the increasing risk of future nuclear disasters, we aim to provide important insides into health consequences of such disasters on organisms being relevant models for human biology.