Department of General Psychology, University of Padova, Via Venezia 8, ZIP code I-35131, Padova, Italy.
Behav Brain Res. 2010 Jan 20;206(2):208-15. doi: 10.1016/j.bbr.2009.09.019. Epub 2009 Sep 16.
The habenulae are part of an evolutionary conserved conduction system that connects the limbic forebrain areas with midbrain structures and is implicated in important functions such as feeding, mating, avoidance learning, and hormonal response to stress. Very early during zebrafish neurogenesis the parapineal organ migrates near to one habenula, commonly the left, inducing wide left-right habenular asymmetries in gene expression and connectivity. It was posited that this initial symmetry-breaking event determines the development of lateralized brain functions and early differences in epithalamic left-right asymmetry give rise to individual variation in coping styles and personality. We tested these two hypotheses by sorting zebrafish with left or right parapineal at birth using a foxD3:GFP marker and by measuring visual and motor laterality and three personality dimensions as they become adults. Significant differences between fish with opposite parapineal position were found in all laterality tests while the influence of asymmetry of the habenulae on personality was more complex. Fish with atypical right parapineal position, tended to be bolder when inspecting a predator, spent less time in the peripheral portion of an open field and covered a shorter distance when released in the dark. Activity in the open field was not associated to anatomical asymmetry but correlated with laterality of predator inspection that in turn was influenced by parapineal position. One personality dimension, sociality, appeared uncorrelated to both anatomical and functional asymmetries and was instead influenced by the sex of the fish, thus suggesting that other factors, i.e. hormonal, may be implicated in its development.
缰核是连接边缘前脑区域与中脑结构的进化保守传导系统的一部分，它参与了许多重要的功能，如摄食、交配、回避学习和对压力的激素反应。在斑马鱼神经发生的早期，缰核旁器官向一侧（通常是左侧）迁移，导致基因表达和连接的广泛左右缰核不对称。有人提出，这种最初的对称性破缺事件决定了大脑功能的侧化发展，而早期视丘间脑的左右不对称导致了个体在应对方式和个性方面的差异。我们通过使用 foxD3:GFP 标记物在出生时对具有左或右缰核旁器官的斑马鱼进行分类，并在它们成年时测量视觉和运动的偏侧性以及三个个性维度，来检验这两个假设。在所有的偏侧性测试中，具有相反缰核旁器官位置的鱼之间都存在显著差异，而缰核的不对称对个性的影响则更为复杂。具有异常右侧缰核旁器官位置的鱼在检查捕食者时往往更大胆，在开阔场的周边部分停留的时间更少，在黑暗中释放时覆盖的距离也更短。开阔场的活动与解剖学不对称无关，但与捕食者检查的偏侧性相关，而后者又受到缰核旁器官位置的影响。一个个性维度，社交性，与解剖和功能不对称均无相关性，而是受鱼的性别影响，这表明其他因素，如激素，可能与其发育有关。
