Single units in the pigeon brain integrate reward amount and time-to-reward inan impulsive choice task
Single units in the pigeon brain integrate reward amount and time-to-reward inan impulsive choice task
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DOI：
10.1016/j.cub.2005.02.052
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发表时间：
2005-04-12
期刊：
影响因子：
9.2
通讯作者：
Colombo, M
中科院分区：
文献类型：
--
作者：
Kalenscher, T;Windmann, S;Colombo, M
背景：当大奖励前的延迟超过个体的耐受极限时，动物更喜欢小奖励而不是大奖励。这种冲动的选择行为甚至发生在替代策略会产生更优结果的情况下。行为学研究表明，动物的选择是由替代奖励的主观价值所引导的，这些价值是奖励金额和奖励时间的函数。尽管越来越多的药理学和解剖学知识的冲动，它仍然是未知的大脑如何结合奖励金额和时间来奖励的信息，以代表主观reward value.Results：我们训练鸽子之间选择小，立即奖励和大的奖励后，逐渐增加延迟。单细胞记录在鸟类Nidopallium caudolaterale，themammalian前额叶皮层的假定功能类似物，揭示了神经延迟激活减少延迟长度的增加，但也与预期的奖励金额。这种综合神经反应受到奖励量和延迟的调节，如由行为研究得出的主观奖励值的双曲线方程所预测的。此外，神经激活模式反映了当前的奖励偏好和时间点的转变，从大到小rewards.Conclusions：报告的活动调制的预期奖励的时间贬值，除了奖励金额。我们的发现有助于理解神经病理学，如药物成瘾，病理性赌博，额叶综合征和注意力缺陷障碍，其特征是不适当的时间折扣和冲动增加。
Background: Animals prefer small over large rewards when the delays preceding large rewards exceed an individual tolerance limit. Such impulsive choice behavior occurs even in situations in which alternative strategies would yield more optimal outcomes. Behavioral research has shown that an animal's choice is guided by the alternative rewards' subjective values, which are a function of reward amount and time-to-reward. Despite increasing knowledge about the pharmacology and anatomy underlying impulsivity, it is still unknown how the brain combines reward amount and time-to-reward information to represent subjective reward value.Results: We trained pigeons to choose between small, immediate rewards and large rewards delivered after gradually increasing delays. Single-cell recordingsin the avian Nidopallium caudolaterale, the presumed functional analog of themammalian prefrontal cortex, revealed that neural delay activation decreased with increasing delay length but also covaried with the expected reward amount. This integrated neural response was modulated by reward amount and delay, aspredicted by a hyperbolical equation, of subjective reward value derived frombehavioral studies. Furthermore, the neural activation pattern reflected the current reward preference and the time point of the shift from large to small rewards.Conclusions: The reported activity was modulated by the temporal devaluation of the anticipated reward in addition to reward amount. Our findings contributeto the understanding of neuropathologies such as drug addiction, pathologicalgambling, frontal lobe syndrome, and attention-deficit disorders, which are characterized by inappropriate temporal discounting and increased impulsiveness.