Wong Ryan Y, Cummings Molly E
Department of Biological Sciences, W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, N.C., USA.
Brain Behav Evol. 2014;83(3):231-43. doi: 10.1159/000360071. Epub 2014 May 20.
Choosing mates is a commonly shared behavior across many organisms, with important fitness consequences. Variations in female preferences can be due in part to differences in neural and cellular activity during mate selection. Initial studies have begun to identify putative brain regions involved in mate preference, yet the understanding of the neural processes regulating these behaviors is still nascent. In this study, we characterized the expression of a gene involved in synaptogenesis and plasticity (neuroligin-3) and one that codes for the rate-limiting enzyme in dopamine biosynthesis (tyrosine hydroxylase; TH1) in the female Xiphophorus nigrensis (northern swordtail) brain as related to mate preference behavior. We exposed females to a range of different mate choice contexts including two large courting males (LL), two small coercive males (SS), and a context that paired a large courting male with a small coercive male (LS). Neuroligin-3 expression in a mate preference context (LS) showed significant correlations with female preference in two telencephalic areas (Dm and Dl), a hypothalamic nucleus (HV), and two regions associated with sexual and social behavior (POA and Vv). We did not observe any context- or behavior-specific changes in tyrosine hydroxylase mRNA expression concomitant with female preference in any of the brain regions examined. Analysis of TH and neuroligin-3 expression across different brain regions showed that expression patterns varied with the male social environment only for neuroligin-3, where the density of correlated expression between brain regions was positively associated with mate choice contexts that involved a greater number of courting male phenotypes (LS and LL). This study identified regions showing presumed high levels of synaptic plasticity using neuroligin-3, implicating and supporting their roles in female mate preference, but we did not detect any relationship between tyrosine hydroxylase and mate preference with 30 min of stimulus presentation in X. nigrensis. These data suggest that information about potential mates is processed in select forebrain regions and the entire brain shows different degrees of correlated expression depending on the mate preference context.
选择配偶是许多生物共有的行为，具有重要的适应性后果。雌性偏好的差异部分可能归因于择偶过程中神经和细胞活动的不同。初步研究已开始确定与配偶偏好相关的假定脑区，但对调节这些行为的神经过程的理解仍处于起步阶段。在本研究中，我们表征了剑尾鱼属（Xiphophorus nigrensis，即黑剑尾鱼）雌性大脑中参与突触形成和可塑性的基因（神经连接蛋白3）以及编码多巴胺生物合成限速酶的基因（酪氨酸羟化酶；TH1）的表达与配偶偏好行为的关系。我们让雌性处于一系列不同的配偶选择情境中，包括两只大型求偶雄性（LL）、两只小型强迫雄性（SS），以及将一只大型求偶雄性与一只小型强迫雄性配对的情境（LS）。在配偶偏好情境（LS）中，神经连接蛋白3在两个端脑区域（Dm和Dl）、一个下丘脑核（HV）以及与性行为和社会行为相关的两个区域（POA和Vv）中的表达与雌性偏好呈显著相关。在任何被检查的脑区中，我们均未观察到酪氨酸羟化酶mRNA表达伴随雌性偏好出现任何情境特异性或行为特异性变化。对不同脑区中TH和神经连接蛋白3表达的分析表明，仅神经连接蛋白3的表达模式随雄性社会环境而变化，其中脑区之间相关表达的密度与涉及更多求偶雄性表型的配偶选择情境（LS和LL）呈正相关。本研究利用神经连接蛋白3确定了显示出假定高突触可塑性水平的区域，暗示并支持了它们在雌性配偶偏好中的作用，但在黑剑尾鱼中，给予30分钟刺激呈现后，我们未检测到酪氨酸羟化酶与配偶偏好之间存在任何关系。这些数据表明，有关潜在配偶的信息在特定的前脑区域进行处理，并且整个大脑根据配偶偏好情境显示出不同程度的相关表达。
