Neural Mechanisms Regulating Reward Responses

大脑是如何决定什么时候该工作以获取食物或努力寻找配偶呢？根据动物的内部状态，大脑会发生什么变化，从而为特定的奖励分配优先级？在这些实验中，研究人员将研究雌激素如何在雌性大鼠的大脑中发挥作用，减少摄食量和进食动机，同时增强生殖动机。研究人员将研究大脑对之前与奖励配对的提示做出反应时大脑的化学成分。这些研究将调查在不同的荷尔蒙状态下，神经递质多巴胺的变化如何受到与奖励相关的线索的影响。这些结果将加强对激素影响动机和决策过程的作用的理解，并有助于从总体上理解神经可塑性。在雌性大鼠中，雌二醇降低了摄食量和进食动机，同时增强了雌性生殖动机。此外，伏隔核(NAC)中的多巴胺(DA)在呈现先前与奖赏配对的线索时增加，NAC DA与该奖赏的激励显著的归因有关。在不同的激素状态下，DA信号如何受到奖赏相关线索的影响，以及雌二醇影响这些线索的激励突显性的机制，对于我们理解雌性大鼠的动机至关重要。实验将使用快速扫描循环伏安法来测量在不同激素条件下对配偶或食物做出反应时NAC核心和外壳中自发释放的DA，使用我们的新范式来量化雌性生殖动机。DA在雌性从选择食物到选择配偶的转换过程中的作用将被确定。研究生和本科生将参与这些学习。调查结果将通过科学出版物以及在地方和国家一级的会议上作介绍来传播。学生在实验室的具体活动包括实验室技能的前/后评估和大脑规则的开发！向当地和底特律的中学生介绍激励和选择的神经机制。

How does the brain decide when it is time to work to obtain food or put its effort into finding a mate? What changes in the brain to assign priorities to specific rewards depending on the internal state of the animal? In these experiments, the investigators will study how the hormone, estradiol, acts in the brain of the female rat to decrease food intake and the motivation for food, while enhancing reproductive motivation. The investigators will study the chemistry of the brain as it responds to the presentation of a cue that has been previously paired with a reward. These studies will investigate how changes in the neurotransmitter, dopamine, is affected by reward-related cues under different hormonal states. These results will enhance the understanding of the role of hormones to influence motivation and decision making processes, and will contribute to the understanding of neuroplasticity in general. In the female rat, estradiol decreases food intake and the motivation for food while enhancing female reproductive motivation. Further, dopamine (DA) increases in the nucleus accumbens (NAc) upon the presentation of a cue that has been previously paired with a reward, and NAc DA is implicated in attribution of incentive salience for that reward. How DA signaling is affected by reward-related cues under different hormonal states, and the mechanism through which estradiol affects the incentive salience of these cues, is critically important to our understanding of motivation in the female rat. Experiments will use fast scan cyclic voltammetry to measure spontaneous DA release in the core and shell of the NAc during responding for a mate or food under different hormone conditions, using our novel paradigm to quantify female reproductive motivation. The role of DA in mediating the switch from choosing food to choosing a mate in the female will be determined. Graduate students and undergraduates will be involved in these studies. Findings will be disseminated through scientific publications as well as presentations at conferences at the local and national level. Specific activities for students in the laboratory included pre/post assessment of laboratory skills and development of a BrainsRule! presentation to local and Detroit middle school students about the neural mechanisms of motivation and choice.