Byrnes Evan E, Vila Pouca Catarina, Brown Culum
Department of Biological Sciences, Macquarie University, North Ryde NSW 2109, Australia.
Department of Biological Sciences, Macquarie University, North Ryde NSW 2109, Australia.
Behav Brain Res. 2016 May 15;305:239-46. doi: 10.1016/j.bbr.2016.02.033. Epub 2016 Mar 2.
Cerebral lateralization is an evolutionarily deep-rooted trait, ubiquitous among the vertebrates and present even in some invertebrates. Despite the advantages of cerebral lateralization in enhancing cognition and facilitating greater social cohesion, large within population laterality variation exists in many animal species. It is proposed that this variation is maintained due links with inter-individual personality trait differences. Here we explored for lateralization in Port Jackson sharks (Heterodontus portusjacksoni) using T-maze turn and rotational swimming tasks. Additionally, we explored for a link between personality traits, boldness and stress reactivity, and cerebral lateralization. Sharks demonstrated large individual and sex biased laterality variation, with females demonstrating greater lateralization than males overall. Stress reactivity, but not boldness, was found to significantly correlate with lateralization strength. Stronger lateralized individuals were more reactive to stress. Demonstrating laterality in elasmobranchs for the first time indicates ancient evolutionary roots of vertebrate lateralization approximately 240 million years old. Greater lateralization in female elasmobranchs may be related enhancing females' ability to process multiple stimuli during mating, which could increase survivability and facilitate insemination. Despite contrasting evidence in teleost fishes, the results of this study suggest that stress reactivity, and other personality traits, may be linked to variation in lateralization.
大脑偏侧化是一种在进化上根深蒂固的特征，在脊椎动物中普遍存在，甚至在一些无脊椎动物中也有体现。尽管大脑偏侧化在增强认知和促进更强的社会凝聚力方面具有优势，但许多动物物种在群体内部存在较大的偏侧化差异。有人提出，这种差异因与个体个性特征差异的联系而得以维持。在这里，我们使用T型迷宫转向和旋转游泳任务探究了杰克逊港鲨鱼（Heterodontus portusjacksoni）的偏侧化情况。此外，我们还探究了个性特征、大胆程度和应激反应与大脑偏侧化之间的联系。鲨鱼表现出较大的个体和性别偏向性偏侧化差异，总体而言，雌性比雄性表现出更强的偏侧化。研究发现，应激反应而非大胆程度与偏侧化强度显著相关。偏侧化更强的个体对应激反应更敏感。首次在板鳃亚类中证明偏侧化表明脊椎动物偏侧化有大约2.4亿年的古老进化根源。雌性板鳃亚类更强的偏侧化可能与增强雌性在交配过程中处理多种刺激的能力有关，这可能会提高生存能力并促进受精。尽管硬骨鱼中有相反的证据，但本研究结果表明，应激反应和其他个性特征可能与偏侧化差异有关。
