Burghardt W F, Hunt W A
Behavioral Sciences Department, Armed Forces Radiobiology Research Institute, Bethesda, MD 20814-5145.
Pharmacol Biochem Behav. 1989 Jul;33(3):549-54. doi: 10.1016/0091-3057(89)90385-7.
Rats were trained to perform one of three tasks in which responses on a lever delayed the onset of footshock for 20 sec. One task provided a warning tone beginning 15 sec after the last response on the lever and lasting for 5 sec just prior to the presentation of a shock (fixed-interval signalled avoidance), while a second task provided no external cues (unsignalled avoidance). The third task was similar to the fixed-interval signalled avoidance task, except that the warning tone preceding shock began at varying intervals after the last response on the lever (variable-interval signalled avoidance). Animals trained on the signalled avoidance paradigms received fewer shocks than those on the unsignalled avoidance paradigm. After 10 krads of gamma radiation, animals performing on either task with cues were less able to avoid shock, although they recovered somewhat over a 90-min period. The animals not provided cues also experienced more shocks during the first 10 min after irradiation but were relatively less affected in performing the task. Response rates on the bar and the patterns of responding on these tasks were not significantly different after irradiation, except that animals responded after the onset of shock more often after irradiation than before. These results suggest that rats will continue to effectively use task related cues after irradiation, but that the relative degree of behavioral decrement may depend on the initial level of performance or possibly the complexity of the task.
训练大鼠执行三项任务中的一项，在这些任务中，按压杠杆的反应会使足部电击的开始延迟20秒。一项任务是在杠杆上最后一次反应后15秒开始发出警告音，并在电击呈现前持续5秒（固定间隔信号回避），而第二项任务不提供外部线索（无信号回避）。第三项任务与固定间隔信号回避任务相似，只是电击前的警告音在杠杆上最后一次反应后的不同间隔开始（可变间隔信号回避）。接受信号回避范式训练的动物比接受无信号回避范式训练的动物受到的电击更少。在接受10千拉德的γ射线辐射后，执行任何一种有线索任务的动物避免电击的能力都下降了，尽管它们在90分钟内有所恢复。未提供线索的动物在照射后的前10分钟内也受到了更多的电击，但在执行任务时受到的影响相对较小。照射后，杠杆上的反应率和这些任务中的反应模式没有显著差异，只是照射后动物在电击开始后比照射前更频繁地做出反应。这些结果表明，大鼠在照射后将继续有效地利用与任务相关的线索，但行为下降的相对程度可能取决于初始表现水平或任务的复杂性。
