Effects of experience and context on 50-kHz vocalizations in rats
Effects of experience and context on 50-kHz vocalizations in rats
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DOI：
10.1016/j.physbeh.2007.11.031
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发表时间：
2008-03-18
影响因子：
2.9
通讯作者：
Spruijt, Berry
中科院分区：
文献类型：
--
作者：
Woehr, Markus;Houx, Bart;Spruijt, Berry
老鼠可以发出超声波50 kHz的声音，通常认为这反映了动物的积极情绪状态。然而，一些方面质疑50 kHz电话作为积极情感状态指标的可靠性。首先，老鼠在含有其他老鼠气味的新环境中也会散发出它们，甚至在成为物种内侵略的受害者时也会散发出它们。其次，可以观察到呼叫产生中的巨大个体间差异。本研究的目的是进一步探讨奖赏以外的因素对呼唤的影响。实验A表明，50-kHz的电话发射在相对较高的数字在短期隔离测试笼，并在较小的程度上，也在测试过程中，在一个开放的领域和高架加迷宫。尽管个体间存在差异，但呼叫行为在几天内是个体稳定的，无论大鼠是否在有或没有熟悉的大鼠气味的笼子里进行测试。这些数据表明，50 kHz的呼叫不一定是对愉悦或社会刺激的反应。此外，观察到隔离期间的呼叫发射受到先前经验的强烈影响。在食欲辨别任务中反复训练的大鼠在测试笼中短暂隔离期间只发出很少的呼叫，而幼稚大鼠发出大量的50 kHz呼叫，这些呼叫随着时间的推移而减少。最有可能的解释是，大鼠在与笼友分离时会发出叫声，因为第一组大鼠在记录之前接受了训练，而未接触过的大鼠在分离后立即记录。实验B支持了这一解释，实验表明，单独留在笼中的大鼠在与笼中同伴分离后也以50 kHz的频率呼叫。在这两个实验中，大多数50 kHz的叫声都没有频率调制，这支持了这种亚型具有社会协调功能的建议。目前的研究结果敦促对超声发声进行复杂的光谱分析，并在解释50 kHz发声时谨慎，因为这些叫声的特定亚型可能发生在不一定令大鼠愉快的环境中，并且受到先前经验和巨大个体差异的影响。(c)2007年爱思唯尔公司All rights reserved.
Rats can emit ultrasonic 50-kHz vocalizations which are generally assumed to reflect the animals' positive emotional state. However, some aspects question the reliability of 50-kHz calls as indicators of positive affective states. Firstly, rats also emit them in novel environments containing scents of other rats, or even while being victims of intra-species aggression. Secondly, huge inter-individual variability in call production can be observed. The present two studies were conducted to further determine factors other than reward, which may influence or even induce calling. Experiment A showed that 50-kHz calls were emitted in relatively high numbers during short isolation in test cages, and, to a lesser extent, also during testing in an open field and an elevated plus maze. Despite inter-individual variability, calling behavior was individually stable over days and occurred irrespective of whether rats were tested in a cage with or without familiar rat scents. These data indicate that 50-kHz calling is not necessarily a response to the presence of pleasurable or social stimuli. Additionally, it was observed that call emission during isolation is strongly affected by prior experience. Rats that had been trained repeatedly in an appetitive discrimination task emitted only few calls during short isolation in test cages, whereas naive rats emitted high numbers of 50-kHz calls which decreased over time. The most likely explanation is that rats call in response to separation from the cage mate, as the first group was trained before the recordings, while the naive rats were recorded immediately after separation. This explanation was supported by Experiment B, which showed that the rats that remained alone in the home cage also called at 50 kHz after separation from the cage mates. In both experiments, most of the 50-kHz calls were not frequency modulated, which lend support for the suggestion that this subtype has a social-coordinating function. The present findings urge sophisticated spectrographic analysis of ultrasonic vocalizations and caution when interpreting 50-kHz vocalizations, since specific subtypes of these calls can occur in contexts that are not necessarily pleasurable to rats, and are affected by prior experience and huge individual differences. (c) 2007 Elsevier Inc. All rights reserved.