Rats emit distinct types of ultrasonic vocalizations (USV), including high-frequency 50-kHz USV, which occur in appetitive situations. Such 50-kHz USV are thought to reflect positive affective states, for example in case of reward anticipation, and are linked to dopamine signaling. The present study was conducted to investigate whether rats emit 50-kHz USV during a Pavlovian conditioned approach task and whether trait-like differences in 50-kHz USV emission are associated with sign- versus goal-tracking. We hypothesize that individuals engaging more with a cue predicting a food reward will also elicit more 50-kHz USV. In order to test this, we investigated 34 female rats and gauged USV while they underwent a Pavlovian conditioned approach training and extinction paradigm. For one, we found a high subject-dependent variability in the emission of 50-kHz calls. These were not largely affected by state differences, since these 50-kHz USV were observed throughout the task. During task progress and in most subjects, there was a rather complete shift toward goal-tracking, but subjects engaging more with the cue predicting a reward also emitted higher numbers of appetitive 50-kHz calls. This supports the hypothesis that sign-tracking is positively associated with the emission of 50-kHz USV. The high subject-dependent variability in the emission of 50-kHz calls warrants special attention in future appetitive studies.

大鼠发出不同类型的超声波发声 (USV)，包括高频 50 kHz USV，发生在食欲不振的情况下。这种 50 kHz 的 USV 被认为反映了积极的情感状态，例如在奖励预期的情况下，并且与多巴胺信号传导有关。本研究旨在调查大鼠在巴甫洛夫条件接近任务期间是否发射 50 kHz USV，以及 50 kHz USV 发射的特征样差异是否与符号与目标跟踪相关。我们假设个人更多地参与预测食物奖励的线索也会引发更多的 50 kHz USV。为了测试这一点，我们调查了 34 只雌性大鼠并在它们接受巴甫洛夫条件方法训练和灭绝范式时测量了 USV。一方面，我们发现 50 kHz 呼叫的发射存在高度依赖于主题的可变性。这些不受状态差异的影响很大，因为在整个任务中都观察到了这些 50 kHz 的 USV。在任务进展期间和大多数受试者中，有一个相当完整的转向目标跟踪，但更多地参与预测奖励的线索的受试者也发出了更多的食欲 50 kHz 呼叫。这支持了符号跟踪与 50 kHz USV 的发射正相关的假设。50 kHz 呼叫发射的高受试者相关变异性值得在未来的食欲研究中特别注意。有一个向目标跟踪的相当完整的转变，但更多地参与预测奖励的线索的受试者也发出了更多的食欲 50 kHz 呼叫。这支持了符号跟踪与 50 kHz USV 的发射正相关的假设。50 kHz 呼叫发射的高受试者相关变异性值得在未来的食欲研究中特别注意。有一个向目标跟踪的相当完整的转变，但更多地参与预测奖励的线索的受试者也发出了更多的食欲 50 kHz 呼叫。这支持了符号跟踪与 50 kHz USV 的发射正相关的假设。50 kHz 呼叫发射的高受试者相关变异性值得在未来的食欲研究中特别注意。