Pickens Charles L, Saddoris Michael P, Setlow Barry, Gallagher Michela, Holland Peter C, Schoenbaum Geoffrey
Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, Maryland 21218, USA.
J Neurosci. 2003 Dec 3;23(35):11078-84. doi: 10.1523/JNEUROSCI.23-35-11078.2003.
The orbitofrontal cortex (OFC) and basolateral amygdala (BLA) are critical for using learned representations of outcomes to guide behavior. Neurophysiological findings suggest complementary roles in which the BLA acquires associations between cues and outcomes and the OFC subsequently uses them to guide behavior. Here, we have used a reinforcer devaluation paradigm to test this hypothesis. In this paradigm, rats are first trained to associate a light conditioned stimulus (CS) with a food outcome, and then the food is devalued by pairing it with illness. After this devaluation procedure, responding to the CS is assessed in a single probe session. Previously, we have shown that BLA and OFC lesions made before training do not affect the acquisition of conditioned responding but do impair the sensitivity of that responding to reinforcer devaluation. Rats with such lesions fail to exhibit the spontaneous decrease in conditioned responding to the light cue observed in controls in the probe test. Here, we have extended those findings by showing that performance in the probe test is impaired by OFC lesions made after light-food conditioning but not by BLA lesions made after that training. These findings indicate that the OFC and BLA play different roles in mediating normal goal-directed performance in this, and likely other, settings. The BLA seems critical to forming representations linking cues to the incentive properties of outcomes but not for maintaining these representations in memory, updating them with new information, or for expressing them in behavior. In contrast, the OFC seems essential for one or more of these latter processes.
眶额叶皮质(OFC)和基底外侧杏仁核(BLA)对于利用习得的结果表征来指导行为至关重要。神经生理学研究结果表明,它们具有互补作用,即BLA负责获取线索与结果之间的关联,随后OFC利用这些关联来指导行为。在此,我们采用了强化物贬值范式来验证这一假设。在该范式中,首先训练大鼠将光条件刺激(CS)与食物结果建立关联,然后通过将食物与疾病配对使其贬值。在这个贬值程序之后,在单个探测实验中评估对CS的反应。此前,我们已经表明,在训练前进行的BLA和OFC损伤不会影响条件反应的习得,但会损害该反应对强化物贬值的敏感性。患有此类损伤的大鼠在探测测试中无法表现出在对照组中观察到的对光线索的条件反应的自发减少。在此,我们扩展了这些发现,表明在光 - 食物条件反射后进行的OFC损伤会损害探测测试中的表现,而在该训练后进行的BLA损伤则不会。这些发现表明,在这种以及可能其他的情境中,OFC和BLA在介导正常的目标导向行为中发挥着不同的作用。BLA对于形成将线索与结果的激励属性联系起来的表征似乎至关重要,但对于在记忆中维持这些表征、用新信息更新它们或在行为中表达它们并非如此。相比之下,OFC对于这些后期过程中的一个或多个似乎是必不可少的。