Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, Newark, NJ, United States.
NeuroBehavioral Research Laboratory, Department of Veterans Affairs, New Jersey Health Care System, East Orange, NJ, United States.
Prog Neuropsychopharmacol Biol Psychiatry. 2018 Mar 2;82:195-204. doi: 10.1016/j.pnpbp.2017.11.015. Epub 2017 Nov 22.
Differential processing of danger and safety signals may underlie symptoms of anxiety disorders and posttraumatic stress disorder. One symptom common to these disorders is pathological avoidance. The present study examined whether danger and safety signals influence avoidance differently in anxiety-vulnerable Wistar-Kyoto (WKY) rats and Sprague Dawley (SD) rats. SD and WKY rats were tested in a novel progressive ratio avoidance task with and without danger or safety signals. Two components of reinforcement, hedonic value and motivation, were determined by fitting an exponentiated demand equation to the data. Hedonic value of avoidance did not differ between SD and WKY rats, but WKY rats had greater motivation to avoid than SD rats. Removal of the safety signal reduced motivation to avoid in SD, but not WKY, rats. Removal of the danger signal did not alter avoidance in either strain. When danger and safety signals were presented simultaneously, WKY rats responded to the danger signals, whereas SD rats responded to the safety signal. The results provide evidence that 1) safety signals enhance motivation to avoid in SD rats, 2) both danger and safety signals influence motivation in WKY rats, and 3) danger signals take precedence over safety signals when presented simultaneously in WKY rats. Thus, anxiety vulnerability is associated with preferential use of danger signals to motivate avoidance. The differential use of danger and safety signals has important implications for the etiology and treatment of pathological avoidance in anxiety disorders and posttraumatic stress disorder.
危险和安全信号的差异处理可能是焦虑症和创伤后应激障碍症状的基础。这些疾病的一个共同症状是病理性回避。本研究考察了危险和安全信号是否会对易焦虑的 Wistar-Kyoto（WKY）大鼠和 Sprague Dawley（SD）大鼠的回避行为产生不同的影响。SD 和 WKY 大鼠在有无危险或安全信号的情况下进行了新的递增比例回避任务测试。通过将指数需求方程拟合到数据中，确定了回避的两个强化成分，即享乐价值和动机。SD 和 WKY 大鼠之间的回避享乐价值没有差异，但 WKY 大鼠比 SD 大鼠有更大的回避动机。在 SD 大鼠中，去除安全信号会降低回避动机，但在 WKY 大鼠中则不会。在两种品系中，去除危险信号都不会改变回避行为。当同时呈现危险和安全信号时，WKY 大鼠对危险信号做出反应，而 SD 大鼠对安全信号做出反应。结果表明，1）安全信号增强了 SD 大鼠的回避动机，2）危险和安全信号都影响了 WKY 大鼠的动机，3）当同时呈现危险和安全信号时，WKY 大鼠优先使用危险信号来激发回避。因此，焦虑易感性与优先使用危险信号来激发回避有关。危险和安全信号的差异使用对焦虑症和创伤后应激障碍中病理性回避的病因学和治疗具有重要意义。
