Specific 50-kHz vocalizations are tightly linked to particular types of behavior in juvenile rats anticipating play

Rat ultrasonic vocalizations have been suggested to be either a byproduct of physical movement or, in the case of 50-kHz calls, a means to communicate positive affect. Yet there are up to 14 distinct types of 50-kHz calls, raising issues for both explanations. To discriminate between these theories and address the purpose for the numerous 50-kHz call types, we studied single juvenile rats that were waiting to play with a partner, a situation associated with a high number of 50-kHz calls. We used a Monte-Carlo shuffling procedure to identify vocalization-behavior correlations that were statistically different from chance. We found that certain call types (“split”, “composite” and “multi-step”) were strongly associated with running and jumping while other call types (those involving “trills”) were more common during slower movements. Further, non-locomotor states such as resting and rearing were strongly predictive of a lack of vocalizations. We also found that the various sub-types of US...有研究提出，大鼠超声发声（Rat Ultrasonic Vocalizations）要么是躯体运动的副产物，要么就50千赫兹叫声（50-kHz calls）而言，是传递积极情绪的交流手段。然而50千赫兹叫声存在多达14种不同亚型，这让上述两种解释均面临矛盾。为甄别这两种理论，并厘清如此多样的50千赫兹叫声亚型的存在意义，我们对等待与同伴玩耍的幼年大鼠个体展开了研究——该情境下50千赫兹叫声的产生频率极高。我们采用蒙特卡洛洗牌程序（Monte-Carlo shuffling procedure）来识别与随机概率存在统计学差异的发声-行为相关性。研究发现，部分叫声亚型（如“拆分型”“复合型”与“多步型”）与奔跑、跳跃行为显著相关，而另一些带有“颤音”特征的叫声亚型则在慢速运动中更为常见。此外，静息与直立探察这类非运动状态可强烈预测无发声行为的出现。我们还发现，超声发声（US，Ultrasonic Vocalizations）的各类亚型……