Department of Psychology, Seton Hall University, South Orange, NJ, 07079, USA.
Cogn Affect Behav Neurosci. 2022 Aug;22(4):703-721. doi: 10.3758/s13415-021-00897-7. Epub 2021 Apr 12.
When an object conditioned stimulus (CS) is paired with a food unconditioned stimulus (US), anticipatory goal-directed action directed at the US location (goal tracking) is accompanied by behavior directed at the object CS (sign tracking). Sign-tracking behavior appears to be compulsive and habit-like and predicts increased vulnerability to the addictive potential of drugs in animal models. A large body of the literature also suggests that environmental enrichment protects against the development of addiction-prone phenotypes. Thus, we investigated whether compulsive-like sign tracking develops in environmentally enriched rats trained directly in their enriched home environment. We demonstrate that adolescent enriched-housed male Sprague-Dawley rats readily sign track a 5% ethanol bottle CS in their home environment and at a rate higher than adolescent standard-housed rats. We also show that enriched adolescent rats sign track less than enriched adult-trained rats and that acute isolation stress affects sign- and goal-tracking performance of adolescents and adults differently. Sign tracking increased more in the adult than the adolescent rats. Whereas the younger rats showed a decrease in goal tacking after the final stressor manipulation, the adults showed increased goal tracking. Our results are consistent with recent studies, which suggest that although sign tracking performance is compulsive-like, it is not as inflexible and habit-like as previously assumed. Testing in an enriched home environment with object CSs having greater affordance than "neutral" lever CSs may provide greater ecological relevance for investigating the development and expression of adaptive and compulsive-like behaviors in translational research.
当一个物体条件刺激 (CS) 与食物非条件刺激 (US) 配对时，指向 US 位置的预期目标导向动作 (目标跟踪) 伴随着指向物体 CS 的行为 (符号跟踪)。符号跟踪行为似乎是强迫性的和习惯化的，并预测在动物模型中对药物成瘾潜力的易感性增加。大量文献还表明，环境丰富可以防止成瘾倾向表型的发展。因此，我们研究了在直接在丰富的家庭环境中训练的环境丰富的大鼠中是否会发展出强迫性的符号跟踪。我们证明，在他们的家庭环境中，青少年丰富饲养的雄性 Sprague-Dawley 大鼠很容易对 5%乙醇瓶 CS 进行符号跟踪，其速度高于青少年标准饲养的大鼠。我们还表明，丰富的青少年大鼠的符号跟踪少于丰富的成年训练大鼠，急性隔离应激对青少年和成年大鼠的符号和目标跟踪表现有不同的影响。符号跟踪在成年大鼠中比在青少年大鼠中增加更多。虽然年轻大鼠在最后一次应激源操作后目标跟踪减少，但成年大鼠的目标跟踪增加。我们的结果与最近的研究一致，这些研究表明，尽管符号跟踪表现具有强迫性，但它并不像以前假设的那样不灵活和习惯化。在具有比“中性”杠杆 CS 更大可及性的物体 CS 丰富的家庭环境中进行测试，可能为研究适应性和强迫性行为的发展和表达提供更具生态相关性，以进行转化研究。
