Neural correlates of variations in event processing during learning in basolateral amygdala.
Neural correlates of variations in event processing during learning in basolateral amygdala.
复制标题
DOI：
10.1523/jneurosci.5781-09.2010
复制
发表时间：
2010-02-17
期刊：
影响因子：
--
通讯作者：
Schoenbaum G
中科院分区：
文献类型：
--
作者：
Roesch MR;Calu DJ;Esber GR;Schoenbaum G
多巴胺神经元在奖励预测中发出错误信号的发现表明，从动物行为研究中凭经验得出的概念可以用来理解奖励学习的神经实现。然而，与阶段性多巴胺活动相关的学习理论模型将对线索和奖励等事件的注意力视为静态量。其他模型，例如皮尔斯霍尔模型，提出学习可能会受到这些事件处理过程中变化的影响。这些账户的一个关键特征是事件处理是通过无符号而不是有符号的奖励预测错误来调节的。在这里，我们通过记录行为任务中的单个单元来测试大鼠基底外侧杏仁核的神经活动是否符合这种模式，其中奖励被意外地提供或省略。我们报告说，奖励时的神经活动提供了一个无符号误差信号，其特征与这些模型假设的特征一致。这种神经信号在奖励发生变化后立即增加，并且无论奖励的价值增加还是减少，都会明显出现更强烈的放电。此外，正如这些模型所预测的那样，由于对奖励的期望一再被违反，解雇的变化在几次试验中发生了。这种神经信号与奖励变化后更快地定向到预测线索相关，并且通过基底外侧杏仁核失活来消除该信号会破坏这种定向变化并延迟响应奖励变化的学习。这些结果表明基底外侧杏仁核在学习注意力方面发挥着关键作用。
The discovery that dopamine neurons signal errors in reward prediction has demonstrated that concepts empirically-derived from the study of animal behavior, can be used to understand the neural implementation of reward learning. Yet the learning theory models linked to phasic dopamine activity treat attention to events such as cues and rewards as static quantities; other models, such as Pearce-Hall, propose that learning might be influenced by variations in processing of these events. A key feature of these accounts is that event processing is modulated by unsigned rather than signed reward prediction errors. Here we tested whether neural activity in rat basolateral amygdala conforms to this pattern by recording single-units in a behavioral task in which rewards were unexpectedly delivered or omitted. We report that neural activity at the time of reward in provided an unsigned error signal with characteristics consistent with those postulated by these models. This neural signal increased immediately after a change in reward, and stronger firing was evident whether the value of the reward increased or decreased. Further, as predicted by these models, the change in firing developed over several trials as expectations for reward were repeatedly violated. This neural signal was correlated with faster orienting to predictive cues after changes in reward, and abolition of the signal by inactivation of basolateral amygdala disrupted this change in orienting and retarded learning in response to changes in reward. These results suggest that basolateral amygdala serves a critical function in attention for learning.