Brus Maïna, Meurisse Maryse, Keller Matthieu, Lévy Frédéric
INRA, UMR 85, Physiologie de la Reproduction et des Comportements Nouzilly, France ; CNRS, UMR 7247 Nouzilly, France ; Université François Rabelais Tours, France ; IFCE Nouzilly, France.
Front Behav Neurosci. 2014 Feb 18;8:53. doi: 10.3389/fnbeh.2014.00053. eCollection 2014.
New neurons are continuously added in the dentate gyrus (DG) and the olfactory bulb of mammalian brain. While numerous environmental factors controlling survival of newborn neurons have been extensively studied, regulation by social interactions is less documented. We addressed this question by investigating the influence of parturition and interactions with the young on neurogenesis in sheep mothers. Using Bromodeoxyuridine, a marker of cell division, in combination with markers of neuronal maturation, the percentage of neuroblasts and new mature neurons in the olfactory bulb and the DG was compared between groups of parturient ewes which could interact or not with their lamb, and virgins. In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures. We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis. In the olfactory bulb, the suppressive effect on neuroblasts was dependent on interactions with the young whereas in the DG the decrease in new mature neurons was associated with parturition. In addition, dendritic length and number of nodes of neuroblasts were significantly enhanced by interactions with the lamb in the olfactory bulb but not in the DG. Because interactions with the young involved learning of the olfactory signature of the lamb, we hypothesize that this learning is associated with a down-regulation in olfactory neurogenesis and an enhancement of olfactory neuroblast maturation. Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor.
在哺乳动物大脑的齿状回（DG）和嗅球中，新神经元不断生成。虽然众多控制新生神经元存活的环境因素已得到广泛研究，但社会互动对其调节的记录较少。我们通过研究分娩及与幼崽的互动对绵羊母亲神经发生的影响来解决这个问题。使用细胞分裂标记物溴脱氧尿苷，并结合神经元成熟标记物，比较了可与羔羊互动或不可互动的分娩母羊组以及未生育母羊组嗅球和DG中神经母细胞和新成熟神经元的百分比。此外，通过测量这两个结构中神经母细胞的树突分支进行了形态学分析。我们发现产后时期与嗅觉和海马体成年神经发生的减少有关。在嗅球中，对神经母细胞的抑制作用取决于与幼崽的互动，而在DG中，新成熟神经元的减少与分娩有关。此外，与羔羊的互动显著增加了嗅球中神经母细胞的树突长度和节点数量，但在DG中没有。由于与幼崽的互动涉及对羔羊嗅觉特征的学习，我们推测这种学习与嗅觉神经发生的下调和嗅球神经母细胞成熟的增强有关。我们的假设是，较少的新神经元减少了嗅球中的细胞竞争，并增强了那些被选择参与幼崽气味学习的新神经元的成熟。
