Abstract

The neural systems that underlie reinforcement learning (RL) allow animals to adapt to changes in their environment. In the present study, we examined the hypothesis that the amygdala would have a preferential role in learning the values of visual objects. We compared a group of monkeys (Macaca mulatta) with amygdala lesions to a group of unoperated controls on a two-armed bandit reversal learning task. The task had two conditions. In the What condition, the animals had to learn to select a visual object, independent of its location. And in the Where condition, the animals had to learn to saccade to a location, independent of the object at the location. In both conditions choice-outcome mappings reversed in the middle of the block. We found that monkeys with amygdala lesions had learning deficits in both conditions. Monkeys with amygdala lesions did not have deficits in learning to reverse choice-outcome mappings. Rather, amygdala lesions caused the monkeys to become overly sensitive to negative feedback which impaired their ability to consistently select the more highly valued action or object. These results imply that the amygdala is generally necessary for RL.

中文翻译：

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杏仁核损伤对猕猴基于对象与基于动作的学习的影响。

摘要

强化学习 (RL) 的神经系统使动物能够适应环境的变化。在本研究中，我们检验了杏仁核在学习视觉对象的价值方面具有优先作用的假设。我们比较了一组猴子（猕猴) 在两臂老虎机逆转学习任务中对一组未操作的对照组进行杏仁核损伤。该任务有两个条件。在什么条件下，动物必须学会选择一个视觉对象，而与它的位置无关。在 Where 条件下，动物必须学会扫视到一个位置，而与该位置的物体无关。在这两种情况下，选择-结果映射在块的中间反转。我们发现患有杏仁核损伤的猴子在这两种情况下都有学习缺陷。患有杏仁核病变的猴子在学习逆转选择结果映射方面没有缺陷。相反，杏仁核损伤导致猴子对负反馈过于敏感，这削弱了它们始终如一地选择更有价值的动作或对象的能力。