Attention for learning signals in anterior cingulate cortex.
Attention for learning signals in anterior cingulate cortex.
复制标题
DOI：
10.1523/jneurosci.4715-11.2011
复制
发表时间：
2011-12-14
期刊：
影响因子：
--
通讯作者：
Roesch MR
中科院分区：
文献类型：
--
作者：
Bryden DW;Johnson EE;Tobia SC;Kashtelyan V;Roesch MR
学习理论认为，当奖励意外发生变化时，动物会注意到相关的环境线索，这样才能进行学习。我们之前已经证明，杏仁基底外侧核(ABL)的活动对奖赏价值的意外变化做出反应，这与皮尔斯和霍尔提出的无符号预测误差信号理论一致。然而，只有在意外的奖励发放时，活动才会发生变化，而不是在动物需要注意到条件刺激来预测奖励的时候。这表明，大脑中一定有一个不同的区域发出了学习所需注意力的信号。前扣带回皮质(ACC)可能是完成这一功能的一个候选区域。为了验证这一假设，我们记录了ACC中单个神经元执行相同的行为任务，我们已经用来分离多巴胺和ABL神经元中的有符号预测错误。在这项任务中，老鼠在产生不同大小和延迟的两口油井中进行选择，以奖励。与前人的工作一致，我们发现ACC检测到佣金错误和奖励预测错误。我们还发现，线索采样过程中的活动编码了奖赏大小，但不期望延迟奖赏。最后，在试验中，在意想不到的价值上下变化后注意力增加的试验中，ACC的活动增加。我们的结论是，ACC不仅发出了先前报道的奖赏预测错误的信号，而且还发出了在这些错误之后的试验学习过程中需要增强神经资源的信号。
Learning theory suggests that animals attend to pertinent environmental cues when reward contingencies unexpectedly change so that learning can occur. We have previously shown that activity in basolateral nucleus of amygdala (ABL) responds to unexpected changes in reward value, consistent with unsigned prediction error signals theorized by Pearce and Hall. However, changes in activity were only present at the time of unexpected reward delivery, not during the time when the animal needed to attend to conditioned stimuli that would come to predict the reward. This suggested that a different brain area must be signaling the need for attention necessary for learning. One likely candidate to fulfill this role is the anterior cingulate cortex (ACC). To test this hypothesis, we recorded from single neurons in ACC as they performed the same behavioral task that we have used to dissociate signed from unsigned prediction errors in dopamine and ABL neurons. In this task rats chose between two fluid wells that produced varying magnitudes of and delays to reward. Consistent with previous work, we found that ACC detected errors of commission and reward prediction errors. We also found that activity during cue sampling encoded reward size, but not expected delay to reward. Finally, activity in ACC was elevated during trials in which attention was increased following unexpected up- and down-shifts in value. We conclude that ACC not only signals errors in reward prediction as previously reported, but also signals the need for enhanced neural resources during learning on trials subsequent to those errors.