Jiménez-Morales Nayeli, Mendoza-Ángeles Karina, Porras-Villalobos Mercedes, Ibarra-Coronado Elizabeth, Roldán-Roldán Gabriel, Hernández-Falcón Jesús
Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico.
Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico.
Neurobiol Learn Mem. 2018 Jan;147:79-89. doi: 10.1016/j.nlm.2017.11.017. Epub 2017 Dec 2.
Under laboratory conditions, crayfish establish hierarchical orders through agonistic encounters whose outcome defines the dominant one and one, or more, submissive animals. These agonistic encounters are ritualistic, based on threats, pushes, attacks, grabs, and avoidance behaviors that include retreats and escape responses. Agonistic behavior in a triad of unfamiliar, size-matched animals is intense on the first day of social interaction and the intensity fades on daily repetitions. The dominant animal keeps its status for long periods, and the submissive ones seem to remember 'who the boss is'. It has been assumed that animals remember and recognize their hierarchical status by urine signals, but the putative substance mediating this recognition has not been reported. The aim of this work was to characterize this hierarchical recognition memory. Triads of unfamiliar crayfish (male animals, size and weight-matched) were faced during standardized agonistic protocols for five consecutive days to analyze memory acquisition dynamics (Experiment 1). In Experiment 2, dominant crayfish were shifted among triads to disclose whether hierarchy depended upon individual recognition memory or recognition of status. The maintenance of the hierarchical structure without behavioral reinforcement was assessed by immobilizing the dominant animal during eleven daily agonistic encounters, and considering any shift in the dominance order (Experiment 3). Standard amnesic treatments (anisomycin, scopolamine or cold-anesthesia) were given to all members of the triads immediately after the first interaction session to prevent individual recognition memory consolidation and evaluate its effect on the hierarchical order (Experiment 4). Acquisition of hierarchical recognition occurs at the first agonistic encounter and agonistic behavior gradually diminishes in the following days; animals keep their hierarchical order despite the inability of the dominant crayfish to attack the submissive ones. Finally, blocking of protein synthesis or muscarinic receptors and cold anesthesia impair memory consolidation. These findings suggest that agonistic encounters induces the acquisition of a robust and lasting social recognition memory in crayfish.
在实验室条件下，小龙虾通过争斗性遭遇建立等级秩序，争斗结果确定出占主导地位的一只以及一只或多只处于从属地位的动物。这些争斗性遭遇是程式化的，基于威胁、推搡、攻击、抓取以及包括撤退和逃避反应在内的回避行为。在由三只不熟悉且体型相当的动物组成的群体中，争斗行为在社交互动的第一天很激烈，随着每天重复进行，其激烈程度会逐渐减弱。占主导地位的动物会长时间保持其地位，而处于从属地位的动物似乎记住了“谁是老大”。人们一直认为动物通过尿液信号记住并识别它们的等级地位，但尚未报道介导这种识别的假定物质。这项研究的目的是对这种等级识别记忆进行特征描述。连续五天让三组不熟悉的小龙虾（雄性，体型和体重相当）在标准化的争斗规程中相互对抗，以分析记忆获取动态（实验1）。在实验2中，将占主导地位的小龙虾在不同组之间调换，以揭示等级秩序是取决于个体识别记忆还是地位识别。通过在11次每日争斗性遭遇期间使占主导地位的动物无法行动，并考虑优势顺序的任何变化，来评估在没有行为强化的情况下等级结构的维持情况（实验3）。在第一次互动环节结束后，立即对三组中的所有成员进行标准的遗忘处理（茴香霉素、东莨菪碱或冷麻醉），以防止个体识别记忆巩固，并评估其对等级秩序 的影响（实验4）。等级识别在第一次争斗性遭遇时发生，在接下来的日子里争斗行为逐渐减少；尽管占主导地位的小龙虾无法攻击处于从属地位的小龙虾，但动物们仍保持其等级秩序。最后，蛋白质合成或毒蕈碱受体的阻断以及冷麻醉会损害记忆巩固作用。这些发现表明，争斗性遭遇会促使小龙虾获得强大而持久的社会识别记忆。
