Neurons in Monkey Dorsal Raphe Nucleus Code Beginning and Progress of Step-by-Step Schedule, Reward Expectation, and Amount of Reward Outcome in the Reward Schedule Task
Neurons in Monkey Dorsal Raphe Nucleus Code Beginning and Progress of Step-by-Step Schedule, Reward Expectation, and Amount of Reward Outcome in the Reward Schedule Task
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DOI：
10.1523/jneurosci.4388-12.2013
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发表时间：
2013-02-20
影响因子：
5.3
通讯作者：
Shidara, Munetaka
中科院分区：
文献类型：
--
作者：
Inaba, Kiyonori;Mizuhiki, Takashi;Shidara, Munetaka
中缝背核是大脑中血清素的主要来源。它与大脑中与奖励处理相关的区域相连，神经元表现出与预测的奖励结果相关的活动。临床观察也表明，它在保持警觉性方面很重要，它在成瘾中的明显作用似乎与奖励处理有关。在这里，我们研究了在多试验计划中，背中叶神经元是否携带有关奖励结果和任务进展的信号。我们从两只猴子的背缝中记录了98个单个神经元。猴子进行一、二或三次视觉辨别试验（时间表），获得一、二或三滴液体。在有效提示条件下，视觉提示的长度和亮度分别表示计划进度和奖励金额。在随机提示条件下，视觉提示在时间长度和奖励数量方面是随机呈现的。我们发现了关于(1)计划开始，(2)奖励期望，(3)奖励结果和(4)奖励数量的信息编码在平均触发率中。信息理论分析表明，神经元反应的时间变化包含了与奖励计划进展相关的附加信息，而不仅仅是区分计划开始或奖励/无奖励。当考虑到解剖学、生理学和行为学上对中缝的所有了解时，关于任务进展和预测奖励结果的丰富编码使中缝成为在整个大脑中提供协调持久目标寻求行为的信号的强有力候选者。
The dorsal raphe nucleus is the major source of serotonin in the brain. It is connected to brain regions related to reward processing, and the neurons show activity related to predicted reward outcome. Clinical observations also suggest that it is important in maintaining alertness and its apparent role in addiction seems to be related to reward processing. Here, we examined whether the neurons in dorsal raphe carry signals about reward outcome and task progress during multitrial schedules. We recorded from 98 single neurons in dorsal raphe of two monkeys. The monkeys perform one, two, or three visual discrimination trials (schedule), obtaining one, two, or three drops of liquid. In the valid cue condition, the length and brightness of a visual cue indicated schedule progress and reward amount, respectively. In the random cue condition, the visual cue was randomly presented with respect to schedule length and reward amount. We found information encoded about (1) schedule onset, (2) reward expectation, (3) reward outcome, and (4) reward amount in the mean firing rates. Information theoretic analysis showed that the temporal variation of the neuronal responses contained additional information related to the progress of the schedule toward the reward rather than only discriminating schedule onset or reward/no reward. When considered in light of all that is known about the raphe in anatomy, physiology, and behavior, the rich encoding about both task progress and predicted reward outcome makes the raphe a strong candidate for providing signals throughout the brain to coordinate persistent goal-seeking behavior.