Michigan Neuroscience Institute, University of Michigan, Ann Arbor 48109, United States of America.
Neuroscience Graduate Program, University of Michigan, Ann Arbor 48109, United States of America.
Horm Behav. 2024 Aug;164:105609. doi: 10.1016/j.yhbeh.2024.105609. Epub 2024 Jul 30.
Cues in the environment become predictors of biologically relevant stimuli, such as food, through associative learning. These cues can not only act as predictors but can also be attributed with incentive motivational value and gain control over behavior. When a cue is imbued with incentive salience, it attains the ability to elicit maladaptive behaviors characteristic of psychopathology. We can capture the propensity to attribute incentive salience to a reward cue in rats using a Pavlovian conditioned approach paradigm, in which the presentation of a discrete lever-cue is followed by the delivery of a food reward. Upon learning the cue-reward relationship, some rats, termed sign-trackers, develop a conditioned response directed towards the lever-cue; whereas others, termed goal-trackers, approach the food cup upon lever-cue presentation. Here, we assessed the effects of systemic corticosterone (CORT) on the acquisition and expression of sign- and goal-tracking behaviors in male and female rats, while examining the role of the vendor (Charles River or Taconic) from which the rats originated in these effects. Treatment naïve male and female rats from Charles River had a greater tendency to sign-track than those from Taconic. Administration of CORT enhanced the acquisition of sign-tracking behavior in males from Charles River and females from both vendors. Conversely, administration of CORT had no effect on the expression of the conditioned response. These findings demonstrate a role for CORT in cue-reward learning and suggest that inherent tendencies towards sign- or goal-tracking may interact with this physiological mediator of motivated behavior.
环境中的线索通过联想学习成为生物相关刺激（如食物）的预测因子。这些线索不仅可以作为预测因子，还可以被赋予激励动机价值，并对行为进行控制。当一个线索被赋予激励显著性时，它就具有了引发精神病理学特征的适应不良行为的能力。我们可以使用巴甫洛夫条件反射方法来评估大鼠对奖励线索赋予激励显著性的倾向，其中离散杠杆线索的呈现紧随食物奖励的出现。在学习到线索-奖励关系后，一些大鼠（称为标志追踪者）会对杠杆线索产生条件反应；而另一些大鼠（称为目标追踪者）则会在杠杆线索呈现时接近食物杯。在这里，我们评估了系统皮质酮（CORT）对雄性和雌性大鼠标志和目标追踪行为的获得和表达的影响，同时研究了大鼠来源的供应商（Charles River 或 Taconic）在这些影响中的作用。来自 Charles River 的未处理的雄性和雌性大鼠比来自 Taconic 的大鼠更倾向于标志追踪。在来自 Charles River 的雄性和来自两个供应商的雌性大鼠中，CORT 的给药增强了标志追踪行为的获得。相反，CORT 的给药对条件反应的表达没有影响。这些发现表明 CORT 在线索-奖励学习中起作用，并表明标志或目标追踪的固有倾向可能与这种动机行为的生理调节剂相互作用。
