Isolating the delay component of impulsive choice in adolescent rats.
Isolating the delay component of impulsive choice in adolescent rats.
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DOI：
10.3389/fnint.2014.00003
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发表时间：
2014
影响因子：
3.5
通讯作者：
Richardson HN
中科院分区：
文献类型：
--
作者：
McClure J;Podos J;Richardson HN
冲动选择——对即时小奖励的偏好超过对延迟大奖励的偏好——与从行为障碍到成瘾的各种心理状况有关。这些联系突出了解剖这种多方面行为特征的各个组成部分的关键需要。延迟折扣任务允许研究人员研究这种行为的一个重要因素：奖励的主观价值在延迟期间如何变化。然而，现有的延迟折扣方法在过程中混淆了不同的奖励大小。在这里，我们提出了一种使用单一恒定奖励大小来评估延迟折扣的新方法。一种补充方法可以保持延迟不变，并评估奖励数量变化的效用。分离这些行为成分可以提高我们探索冲动选择的行为复杂性的能力。我们详细介绍了隔离延迟的方法，并进一步利用这种方法，将其与标准峰值间隔任务配对，以检验延迟折扣的个体差异是否可以用雄性和雌性青春期大鼠的时间感知差异来解释。我们发现，在区分时间间隔方面更精确的老鼠在选择时也不那么冲动。我们的数据表明，时间和延迟折扣的差异并不是因果关系，而是更有可能受到共同因素的影响。此外，我们在出生后28天至42天之间测量的平均水平变化表明，该测试可能捕捉到了这一因素的发育变化。总之，这种分离冲动选择的个体成分（延迟或数量）的新方法可以有效地应用于青少年或成年动物模型，并可能有助于阐明冲动的潜在机制及其与心理障碍的联系。
Impulsive choice—the preference for small immediate rewards over larger delayed rewards—has been linked to various psychological conditions ranging from behavioral disorders to addiction. These links highlight the critical need to dissect the various components of this multifaceted behavioral trait. Delay discounting tasks allow researchers to study an important factor of this behavior: how the subjective value of a rewards changes over a delay period. However, existing methods of delay discounting include a confound of different reward sizes within the procedure. Here we present a new approach of using a single constant reward size to assess delay discounting. A complementary approach could hold delay constant and assess the utility of changing quantities of a reward. Isolating these behavioral components can advance our ability to explore the behavioral complexity of impulsive choice. We present in detail the methods for isolating delay, and further capitalize on this method by pairing it with a standard peak interval task to test whether individual variation in delay discounting can be explained by differences in perception of time in male and female adolescent rats. We find that rats that were more precise in discriminating time intervals were also less impulsive in their choice. Our data suggest that differences in timing and delay discounting are not causally related, but instead are more likely influenced by a common factor. Further, the mean-level change in our measure between post-natal day 28 and 42 suggests this test may be capturing a developmental change in this factor. In summary, this new method of isolating individual components of impulsive choice (delay or quantity) can be efficiently applied in either adolescent or adult animal models and may help elucidate the mechanisms underlying impulsivity and its links to psychological disorders.