Teles Magda C, Cardoso Sara D, Oliveira Rui F
Instituto Superior de Psicologia Aplicada-Instituto UniversitárioLisboa, Portugal; Instituto Gulbenkian de CiênciaOeiras, Portugal; Champalimaud Neuroscience Programme, Champalimaud Centre for the UnknownLisboa, Portugal.
Front Behav Neurosci. 2016 Feb 16;10:16. doi: 10.3389/fnbeh.2016.00016. eCollection 2016.
Social living animals need to adjust the expression of their behavior to their status within the group and to changes in social context and this ability (social plasticity) has an impact on their Darwinian fitness. At the proximate level social plasticity must rely on neuroplasticity in the brain social decision-making network (SDMN) that underlies the expression of social behavior, such that the same neural circuit may underlie the expression of different behaviors depending on social context. Here we tested this hypothesis in zebrafish by characterizing the gene expression response in the SDMN to changes in social status of a set of genes involved in different types of neural plasticity: bdnf, involved in changes in synaptic strength; npas4, involved in contextual learning and dependent establishment of GABAergic synapses; neuroligins (nlgn1 and nlgn2) as synaptogenesis markers; and genes involved in adult neurogenesis (wnt3 and neurod). Four social phenotypes were experimentally induced: Winners and Losers of a real-opponent interaction; Mirror-fighters, that fight their own image in a mirror and thus do not experience a change in social status despite the expression of aggressive behavior; and non-interacting fish, which were used as a reference group. Our results show that each social phenotype (i.e., Winners, Losers, and Mirror-fighters) present specific patterns of gene expression across the SDMN, and that different neuroplasticity genes are differentially expressed in different nodes of the network (e.g., BDNF in the dorsolateral telencephalon, which is a putative teleost homolog of the mammalian hippocampus). Winners expressed unique patterns of gene co-expression across the SDMN, whereas in Losers and Mirror-fighters the co-expression patterns were similar in the dorsal regions of the telencephalon and in the supracommissural nucleus of the ventral telencephalic area, but differents in the remaining regions of the ventral telencephalon. These results indicate that social plasticity relies on multiple neuroplasticity mechanisms across the SDMN, and that there is not a single neuromolecular module underlying this type of behavioral flexibility.
群居动物需要根据其在群体中的地位以及社会环境的变化来调整自身行为的表达，而这种能力（社会可塑性）会影响它们的达尔文适应性。在近端层面，社会可塑性必须依赖于大脑社会决策网络（SDMN）中的神经可塑性，该网络是社会行为表达的基础，以至于相同的神经回路可能根据社会环境表达不同的行为。在这里，我们通过表征SDMN中一组参与不同类型神经可塑性的基因对社会地位变化的基因表达反应，在斑马鱼中验证了这一假设：bdnf参与突触强度的变化；npas4参与情境学习以及GABA能突触的依赖性建立；神经连接蛋白（nlgn1和nlgn2）作为突触形成的标志物；以及参与成体神经发生的基因（wnt3和neurod）。实验诱导了四种社会表型：真实对手互动中的胜者和败者；镜像格斗者，它们与镜子中的自己战斗，因此尽管表现出攻击行为，但社会地位并未改变；以及非互动鱼，用作参考组。我们的结果表明，每种社会表型（即胜者、败者和镜像格斗者）在整个SDMN中呈现出特定的基因表达模式，并且不同的神经可塑性基因在网络的不同节点中差异表达（例如，背外侧端脑的BDNF，它被认为是哺乳动物海马体的硬骨鱼同源物）。胜者在整个SDMN中表达独特的基因共表达模式，而在败者和镜像格斗者中，共表达模式在端脑的背侧区域和腹侧端脑区域的连合上核中相似，但在腹侧端脑的其余区域不同。这些结果表明，社会可塑性依赖于整个SDMN中的多种神经可塑性机制，并且不存在单一的神经分子模块作为这种行为灵活性的基础。
