Orbitofrontal cortex mediates outcome encoding in pavlovian but not instrumental conditioning
Orbitofrontal cortex mediates outcome encoding in pavlovian but not instrumental conditioning
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DOI：
10.1523/jneurosci.5443-06.2007
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发表时间：
2007-05-02
影响因子：
5.3
通讯作者：
Balleine, Bernard W.
中科院分区：
文献类型：
--
作者：
Ostlund, Sean B.;Balleine, Bernard W.
先前的研究表明眶额皮质（OFC）与结果编码有关。然而，目前尚不清楚 OFC 是否选择性地参与巴甫洛夫刺激 - 结果学习，或者它是否也有助于工具性行动 - 结果学习。在实验 1 中，我们通过评估 OFC 双侧损伤对器械杠杆按压性能对训练结果激励值降低（动作测试 - 结果编码）和结果特定巴甫洛夫工具转移（刺激测试 - 结果编码）的敏感性的影响来研究这个问题。我们发现训练后 OFC 损伤并不影响仪器结果贬值，但消除了转移效应。有趣的是，训练前造成的损伤对这两项任务都没有影响。在实验 2 中，我们探讨了在这两个事件之间的潜在偶然性或预测关系被降级后，OFC 参与更新刺激-结果关联。沙姆斯表现出明显的应急学习能力，抑制对不再可靠地预测其结果的刺激的条件反应，同时继续对仍然是不同结果的良好预测因子的控制刺激做出反应。相比之下，OFC 损伤的大鼠停止对两种刺激做出反应，无论其预测状态如何。总之，这些发现表明 OFC 支持巴甫洛夫式的结果编码，但不支持工具性条件反射。
Previous studies have implicated the orbitofrontal cortex (OFC) in outcome encoding. However, it remains unknown whether the OFC is selectively involved in pavlovian stimulus - outcome learning or whether it also contributes to instrumental action - outcome learning. In experiment 1, we investigated this issue by assessing the effects of bilateral lesions of the OFC on the sensitivity of instrumental lever press performance to a reduction in the incentive value of the training outcome (a test of action - outcome encoding) and to outcome-specific pavlovian-instrumental transfer (a test of stimulus - outcome encoding). We found that post-training lesions of the OFC did not affect instrumental outcome devaluation, but abolished the transfer effect. Interestingly, lesions made before training had no effect on either task. In experiment 2, we explored the involvement of the OFC in updating stimulus - outcome associations after the underlying contingency, or predictive relationship, between these two events has been degraded. Shams displayed clear contingency learning, withholding conditioned responding to a stimulus that no longer reliably predicted its outcome while continuing to respond to a control stimulus that remained a good predictor of a different outcome. In contrast, OFC-lesioned rats stopped responding to both stimuli, regardless of their predictive status. Together, these findings suggest that the OFC supports outcome encoding in pavlovian, but not instrumental conditioning.