History- and current instruction-based coding of forthcoming behavioral outcomes in the striatum.
History- and current instruction-based coding of forthcoming behavioral outcomes in the striatum.
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DOI：
10.1152/jn.00779.2007
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发表时间：
2007-12
影响因子：
2.5
通讯作者：
H. Yamada;N. Matsumoto;M. Kimura
中科院分区：
文献类型：
--
作者：
H. Yamada;N. Matsumoto;M. Kimura
动物通过根据行为历史及其结果预测未来的关键事件来优化行为。当奖励和厌恶等行为结果受到当前外部线索的信号时，就会指导采取行动以获得奖励并避免厌恶。基底神经节被认为是基于奖励的适应性行动计划和学习的大脑所在地。为了了解纹状体在编码即将出现的行为反应的结果中的作用，我们解决了两个具体问题。首先，在一系列受指导的行为反应期间，奖励和厌恶的历史如何用于编码纹状体中即将出现的结果？其次，行为反应及其指示结果如何在纹状体中体现？当猴子执行视觉指导的杠杆释放任务以获得奖励、厌恶和声音结果时，我们记录了纹状体中 163 个假定的投射神经元的放电，这些结果的发生可以通过它们的历史来估计。在结果指示之前，该时期激活的神经元子集的放电率随奖励历史（24/44）呈现正或负回归斜率，即自上次奖励试验以来的试验数量，其与当前试验的奖励概率平行变化。厌恶结果也观察到历史效应，但神经元数量少得多 (3/44)。一旦在同一任务中指示结果，神经元就会选择性地编码行为反应之前和之后的结果（奖励，46/70；厌恶，6/70；声音，6/70）。纹状体中即将发生的行为结果的基于历史和当前指令的编码可能是结果导向的行为调节的基础。
Animals optimize behaviors by predicting future critical events based on histories of actions and their outcomes. When behavioral outcomes like reward and aversion are signaled by current external cues, actions are directed to acquire the reward and avoid the aversion. The basal ganglia are thought to be the brain locus for reward-based adaptive action planning and learning. To understand the role of striatum in coding outcomes of forthcoming behavioral responses, we addressed two specific questions. First, how are the histories of reward and aversion used for encoding forthcoming outcomes in the striatum during a series of instructed behavioral responses? Second, how are the behavioral responses and their instructed outcomes represented in the striatum? We recorded discharges of 163 presumed projection neurons in the striatum while monkeys performed a visually instructed lever-release task for reward, aversion, and sound outcomes, whose occurrences could be estimated by their histories. Before outcome instruction, discharge rates of a subset of neurons activated in this epoch showed positive or negative regression slopes with reward history (24/44), that is, to the number of trials since the last reward trial, which changed in parallel with reward probability of current trials. The history effect was also observed for the aversion outcome but in far fewer neurons (3/44). Once outcomes were instructed in the same task, neurons selectively encoded the outcomes before and after behavioral responses (reward, 46/70; aversion, 6/70; sound, 6/70). The history- and current instruction-based coding of forthcoming behavioral outcomes in the striatum might underlie outcome-oriented behavioral modulation.