Most behavioral studies on animals focus on observation of individual subjects. Current paradigms of sociability set aside the social-operant dimension, i.e. acting in favor of another conspecific. We focused on prosocial behavior and reciprocity of male, adult Wild-Type (WT) and Heterozygous (HET) rats for the dopamine-transporter (DAT) gene.

Method

The experiment consisted of 24 rats, of WT (n = 12) and HET (n = 12) genotypes. During training, rats were daily introduced, individually, into an apparatus hosting a suspended syringe, which they learnt to push in order to obtain food therein. Then, twice daily along several weeks, we introduced two rats separated by a grid in the same structure: by syringe-pushing, each subject had the opportunity to donate and receive donations of food. We tested pairs with similar versus different genotype. Eventually, we replaced food reward with polystyrene pieces, to understand if they pushed for actual reward or like a habit.

Results

In general, WT rats had better performance, regardless of reward type, than HET ones. When we crossed partner rats’ genotype (WT-HET pairs), WT rats pushed at peak levels, regardless of food pellet received back (in fact, HET companions pushed less). Couples of WT rats achieved better results than HET ones even when polystyrene, instead of food, was used. Thus,WT rats seem to be a better model for altruistic behavior than HET ones. For this reason, HET rats could represent a model for studies on altered prosocial behavior, to understand the role of DAT gene for impaired social mechanisms.

中文翻译：

---

亲社会行为和互惠的新范式，在 WT 和 HET 大鼠中评估 DAT 基因。

大多数对动物的行为研究都集中在对个体受试者的观察上。当前的社交范式搁置了社会操作维度，即支持另一个同种。我们专注于雄性、成年野生型 (WT) 和杂合 (HET) 大鼠的多巴胺转运蛋白 (DAT) 基因的亲社会行为和互惠性。

方法

实验由 24 只大鼠组成，具有 WT (n = 12) 和 HET (n = 12) 基因型。在训练期间，大鼠每天被单独引入一个装有悬挂注射器的装置，它们学会推动注射器以获得其中的食物。然后，在几周内每天两次，我们引入了由相同结构的网格隔开的两只老鼠：通过注射器推动，每个受试者都有机会捐赠和接受捐赠的食物。我们测试了具有相似与不同基因型的配对。最终，我们用聚苯乙烯片代替了食物奖励，以了解它们是推动实际奖励还是喜欢一种习惯。

结果

一般来说，无论奖励类型如何，WT 大鼠都比 HET 大鼠表现更好。当我们越过伙伴大鼠的基因型（WT-HET 对）时，WT 大鼠的推力达到峰值，而不管收到的食物颗粒（实际上，HET 伙伴推得更少）。即使使用聚苯乙烯代替食物，一对 WT 大鼠也取得了比 HET 更好的结果。因此，WT 大鼠似乎是比 HET 大鼠更好的利他行为模型。出于这个原因，HET 大鼠可以代表研究改变的亲社会行为的模型，以了解 DAT 基因对受损社会机制的作用。