Department of Psychology, Miami University, Oxford, OH 45056.
Department of Psychology, University of Illinois at Chicago, Chicago, IL 60607.
eNeuro. 2017 May 1;4(2). doi: 10.1523/ENEURO.0015-17.2017. eCollection 2017 Mar-Apr.
Animal models of decision-making rely on an animal's motivation to decide and its ability to detect differences among various alternatives. Food reinforcement, although commonly used, is associated with problematic confounds, especially satiety. Here, we examined the use of brain stimulation reward (BSR) as an alternative reinforcer in rodent models of decision-making and compared it with the effectiveness of sugar pellets. The discriminability of various BSR frequencies was compared to differing numbers of sugar pellets in separate free-choice tasks. We found that BSR was more discriminable and motivated greater task engagement and more consistent preference for the larger reward. We then investigated whether rats prefer BSR of varying frequencies over sugar pellets. We found that animals showed either a clear preference for sugar reward or no preference between reward modalities, depending on the frequency of the BSR alternative and the size of the sugar reward. Overall, these results suggest that BSR is an effective reinforcer in rodent decision-making tasks, removing food-related confounds and resulting in more accurate, consistent, and reliable metrics of choice.
动物决策模型依赖于动物进行决策的动机和辨别各种选择之间差异的能力。食物强化虽然常用，但与饱腹感等问题有关。在这里，我们研究了脑刺激奖励（BSR）作为决策的啮齿动物模型中的替代强化物的使用，并将其与糖丸的效果进行了比较。在单独的自由选择任务中，我们比较了不同 BSR 频率的可辨别性与不同数量的糖丸。我们发现 BSR 更具可辨别性，更能激发更大的任务参与度和更一致的对更大奖励的偏好。然后，我们研究了大鼠是否更喜欢 BSR 而非糖丸。我们发现，根据 BSR 替代物的频率和糖丸的大小，动物要么对糖丸奖励有明显的偏好，要么对奖励方式没有偏好。总的来说，这些结果表明 BSR 是啮齿动物决策任务中的一种有效强化物，消除了与食物相关的混淆，并产生了更准确、一致和可靠的选择指标。
