Goodwin Nastacia L, Licata Al M, Power Kelley C, Reitz Kara M, Kamal Yasmin, Beery Annaliese K
Psychology Department, University of Washington, Seattle, WA, 98105, USA.
Neuroscience Program, Smith College, Northampton, MA, 01063, USA.
Sci Rep. 2025 Sep 29;15(1):33523. doi: 10.1038/s41598-025-17920-3.
Friendships-i.e. selective peer relationships-are an important aspect of human behavior, but are rare in rodent species. Meadow voles are seasonally social rodents that form non-reproductive social groups in winter/short day lengths that are selective in nature. Across rodents, oxytocin neurons in the paraventricular nucleus (PVN) of the hypothalamus are typically active during socially salient events, including interaction with novel individuals as well as social separation. To assess whether familiar and novel peer interactions produce different patterns of immunolabeling in a species that forms bonds with familiar individuals, we measured oxytocin neuron immunoreactivity and colabeling with the immediate early gene product cFos. Oxytocin labeling and oxytocin/cFos colabeling were higher after interaction with a novel same-sex conspecific than after reunion with a peer partner. Colabeling was also high after 24 h separation without reunion. Circulating corticosterone concentrations paralleled PVN oxytocin neuron activity. We also investigated whether oxytocin signaling was photoperiod dependent and could contribute to seasonal differences in meadow vole social behavior. Oxytocin receptor densities are known to be higher in multiple brain regions in short day lengths in meadow voles, but we found no concomitant change in PVN oxytocin positive cell count. Together these studies indicate that seasonal changes in behavior correlate with oxytocin signaling at the receptor level, while short term experiences modulated oxytocin neuron activity differentially by social context.
友谊，即选择性的同伴关系，是人类行为的一个重要方面，但在啮齿动物物种中却很罕见。草甸田鼠是季节性群居的啮齿动物，在冬季/短日照时长时形成具有选择性的非繁殖性社会群体。在整个啮齿动物中，下丘脑室旁核（PVN）中的催产素神经元通常在具有社会显著性的事件中活跃，包括与陌生个体的互动以及社会分离。为了评估熟悉和陌生的同伴互动是否会在与熟悉个体建立联系的物种中产生不同的免疫标记模式，我们测量了催产素神经元的免疫反应性以及与即刻早期基因产物cFos的共标记。与陌生同性同种个体互动后，催产素标记和催产素/cFos共标记高于与同伴重聚后。在分离24小时且未重聚后，共标记也很高。循环皮质酮浓度与PVN催产素神经元活性平行。我们还研究了催产素信号是否依赖光周期，以及是否会导致草甸田鼠社会行为的季节性差异。已知草甸田鼠在短日照时长时多个脑区的催产素受体密度较高，但我们发现PVN中催产素阳性细胞计数没有相应变化。这些研究共同表明，行为的季节性变化与受体水平的催产素信号相关，而短期经历根据社会背景对催产素神经元活性有不同的调节作用。
