Department of Neurobiology, Institute of Life Sciences, Israel.
J Neurosci. 2012 May 30;32(22):7519-27. doi: 10.1523/JNEUROSCI.6354-11.2012.
One of the most dramatic events during the life of adult mammals is the transition into motherhood. This transition is accompanied by specific maternal behaviors, displayed by the mother, that ensure the survival and the well-being of her offspring. The execution of these behaviors is most likely accompanied by plastic changes in specific neuronal circuits, but these are still poorly defined. In this work, we studied the mammalian olfactory bulb (OB), which has been shown to be an essential brain region for maternal behaviors in mice. In the OB, we focused on adult-born neurons, which are continuously incorporated into the circuit during adulthood, thus providing a potential substrate for heightened plasticity after parturition. We analyzed the dynamics and morphological characteristics of adult-born granule cells (abGCs), innervating the OB of primiparous lactating mothers, shortly after parturition as well as in naive females. In vivo time-lapse imaging of abGCs revealed that dendritic spines were significantly more stable in lactating mothers compared with naive virgins. In contrast, spine stability of resident GCs remained unchanged after parturition. In addition, while spine size distribution of abGCs was approximately similar between mothers and naive virgins, the spine density of abGCs was lower in lactating mothers and the density of their presynaptic components was higher. These structural features are indicative of enhanced integration of adult-born neurons into the bulbar circuitry of lactating mothers. This enhanced integration may serve as a cellular mechanism, supporting changes in olfactory coding of new mothers during their first days following parturition.
成年哺乳动物生命中最戏剧性的事件之一是过渡到母亲身份。这种转变伴随着母亲表现出的特定母性行为，这些行为确保了她的后代的生存和幸福。这些行为的执行很可能伴随着特定神经元回路的可塑性变化，但这些仍然定义不明确。在这项工作中，我们研究了哺乳动物嗅球（OB），OB 已被证明是小鼠母性行为的重要脑区。在 OB 中，我们专注于成年新生神经元，它们在成年期持续被整合到回路中，因此为分娩后增强的可塑性提供了潜在的基础。我们分析了初产哺乳期母亲和未生育的雌性 OB 中新生颗粒细胞（abGC）的动力学和形态特征。abGC 的体内延时成像显示，与未生育的处女相比，哺乳期母亲的树突棘明显更稳定。相比之下，分娩后常驻 GC 的棘突稳定性保持不变。此外，尽管 abGC 的棘突大小分布在母亲和未生育的处女之间大致相似，但哺乳期母亲的 abGC 棘突密度较低，其突触前成分的密度较高。这些结构特征表明，成年新生神经元在哺乳期母亲的 OB 回路中得到了增强的整合。这种增强的整合可能作为一种细胞机制，支持新母亲在分娩后最初几天嗅觉编码的变化。
