The Role of the Rat Medial Prefrontal Cortex in Adapting to Changes in Instrumental Contingency
The Role of the Rat Medial Prefrontal Cortex in Adapting to Changes in Instrumental Contingency
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DOI：
10.1371/journal.pone.0033302
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发表时间：
2012-04-04
期刊：
影响因子：
3.7
通讯作者：
Marchand, Alain R.
中科院分区：
文献类型：
--
作者：
Coutureau, Etienne;Esclassan, Frederic;Marchand, Alain R.
为了选择适合当前需要的操作，主体必须确定操作和事件之间的关系。对环境的控制取决于可以预测行动后果的程度，正如行动-结果偶然性所描述的那样，即执行行动应该影响结果的概率。我们在第一个实验中评估了内侧前额皮质神经毒性病变大鼠对偶然性变化的适应。研究结果表明，这一大脑区域对于调节工具对负面偶然性的反应并不重要，在这种情况下，老鼠必须避免按压杠杆，因为这种行为会阻止奖励的传递。相比之下，这个大脑区域在非偶然情况下需要减少反应，在这种情况下，同样数量的奖励是自由提供的，行为不再影响结果。在第二个实验中，我们确定这种影响不是由于对行为和结果之间的时间关系的不同感知造成的，因为受损大鼠通常适应逐渐增加的奖励延迟。这些数据表明，内侧前额叶皮层并不直接参与评估动作和奖励率之间的相关性，也不直接参与对奖励延迟的感知。受损大鼠的缺陷似乎包括对偶然奖励和非偶然奖励之间平衡的异常反应。通过强调前额叶区域在适应行为的因果状态中的作用，这些数据有助于我们理解选择任务的神经基础。
In order to select actions appropriate to current needs, a subject must identify relationships between actions and events. Control over the environment is determined by the degree to which action consequences can be predicted, as described by action-outcome contingencies - i.e. performing an action should affect the probability of the outcome. We evaluated in a first experiment adaptation to contingency changes in rats with neurotoxic lesions of the medial prefrontal cortex. Results indicate that this brain region is not critical to adjust instrumental responding to a negative contingency where the rats must refrain from pressing a lever, as this action prevents reward delivery. By contrast, this brain region is required to reduce responding in a non-contingent situation where the same number of rewards is freely delivered and actions do not affect the outcome any more. In a second experiment, we determined that this effect does not result from a different perception of temporal relationships between actions and outcomes since lesioned rats adapted normally to gradually increasing delays in reward delivery. These data indicate that the medial prefrontal cortex is not directly involved in evaluating the correlation between action-and reward-rates or in the perception of reward delays. The deficit in lesioned rats appears to consist of an abnormal response to the balance between contingent and non-contingent rewards. By highlighting the role of prefrontal regions in adapting to the causal status of actions, these data contribute to our understanding of the neural basis of choice tasks.