Kisko Theresa M, Wöhr Markus, Pellis Vivien C, Pellis Sergio M
Behavioral Neuroscience, Experimental and Biological Psychology, Philipps-University of Marburg, Gutenbergstr. 18, D-35032, Marburg, Germany.
Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
Curr Top Behav Neurosci. 2017;30:91-108. doi: 10.1007/7854_2015_432.
When rats engage in playful interactions, they emit appetitive 50-kHz ultrasonic vocalizations (USVs). We investigated the role of 50-kHz USVs in the playful behavior of both juvenile and adult rats. A cohort of juvenile rats was surgically devocalized and allowed to interact with either devocalized or intact partners as juveniles and again as adults. A substantial decrease in playful motivation was seen for pairs of devocalized rats, as well as all intact rats housed with devocalized ones. In pairs in which at least one partner could vocalize, there was no difference in the number of playful interactions as compared to controls. Further investigation revealed that, within the playful episode itself, 50-kHz USVs are more likely to appear before a playful attack is launched than after, regardless of the attacking partner's ability to vocalize, and when one partner is pinned on its back by another, it is the rat that is on top that is more likely to emit 50-kHz USVs. These findings suggest that, for juveniles, 50-kHz USVs may have a critical function in maintaining and facilitating playful motivation, but a more limited role in signaling playful actions. In adults, however, whatever the motivational role of such calling may be, the various kinds of USVs appear to serve critical communicatory functions. For instance, when pairs of adult males that are unfamiliar with one another encounter each other in a neutral arena, they play together, but if one partner is devocalized, there is a significantly higher likelihood that the interaction will escalate to become aggressive. While the relative roles of appetitive 50-kHz and aversive 22-kHz USVs in this context remain to be determined, our overall findings for play in both juveniles and adults suggest that 50-kHz USVs likely have multiple functions, with different functions being more prevalent at some ages and contexts than others.
当大鼠进行玩耍互动时，它们会发出令人愉悦的50千赫兹超声波发声（USV）。我们研究了50千赫兹USV在幼年和成年大鼠玩耍行为中的作用。一组幼年大鼠通过手术使其失声，然后让它们作为幼年大鼠与失声或未失声的伙伴互动，成年后再次进行同样的互动。结果发现，失声大鼠对之间以及与失声大鼠一起饲养的所有未失声大鼠的玩耍动机都大幅下降。在至少有一个伙伴能够发声的配对中，与对照组相比，玩耍互动的次数没有差异。进一步的研究表明，在玩耍过程中，无论攻击伙伴是否能够发声，50千赫兹的USV在发起玩耍攻击之前比之后更有可能出现，而且当一个伙伴被另一个伙伴压在背上时，处于上方的大鼠更有可能发出50千赫兹的USV。这些发现表明，对于幼年大鼠来说，50千赫兹的USV在维持和促进玩耍动机方面可能具有关键作用，但在发出玩耍行为信号方面的作用较为有限。然而，对于成年大鼠来说，无论这种叫声的动机作用如何，各种USV似乎都起着关键的交流作用。例如，当互不熟悉的成年雄性大鼠在中性场地相遇时，它们会一起玩耍，但如果其中一个伙伴失声，互动升级为攻击行为的可能性会显著更高。虽然在这种情况下，令人愉悦的50千赫兹和令人厌恶的22千赫兹USV的相对作用仍有待确定，但我们对幼年和成年大鼠玩耍行为的总体研究结果表明，50千赫兹的USV可能具有多种功能，不同功能在某些年龄和情境中比其他年龄和情境中更为普遍。
