Baylis L L, Gaffan D
Department of Experimental Psychology, Oxford University, UK.
Exp Brain Res. 1991;86(3):617-22. doi: 10.1007/BF00230535.
Cynomolgus monkeys (Macaca fascicularis) with either bilateral amygdalectomy or bilateral ventromedial prefrontal cortical ablations showed abnormal choices between apple, lemon, olive, and meat. Not only did they choose meat or olive more often than normal animals, but also their choices were less consistent from trial to trial than the normal animals' choices were. The same animals were subsequently tested for their ability to learn 2-choice simultaneous visual discriminations between objects which they could suck. The positive object yielded fruit juice, which entered the mouth directly without being seen. Both groups of animals with lesions were severely impaired in this discrimination learning task. The reason why amygdalectomy has little effect on simple object discrimination learning in the Wisconsin General Test Apparatus, we suggest, is that the animal can there associate the visual discriminanda with the visual properties of the food reward, a mechanism which is not available when the reward is unseen. These results add to existing evidence of a close functional relationship between the amygdala and the ventromedial prefrontal cortex, and they support the proposal, derived from previous work, that the amygdala is important for associating visual stimuli with the incentive value of reinforcers.
双侧杏仁核切除术或双侧腹内侧前额叶皮质切除术的食蟹猴（食蟹猕猴）在苹果、柠檬、橄榄和肉之间表现出异常选择。它们不仅比正常动物更频繁地选择肉或橄榄，而且与正常动物相比，它们每次试验的选择一致性更低。随后对相同的动物进行测试，以考察它们学习对可吮吸物体进行二选一同时视觉辨别任务的能力。阳性物体产生果汁，果汁直接进入口中而不被看见。两组有损伤的动物在这种辨别学习任务中都严重受损。我们认为，在威斯康星通用测试设备中，杏仁核切除术对简单物体辨别学习影响不大的原因是，动物在那里可以将视觉辨别物与食物奖励的视觉属性联系起来，而当奖励不可见时，这种机制就不起作用了。这些结果进一步证明了杏仁核与腹内侧前额叶皮质之间存在密切的功能关系，并且支持了从先前研究得出的提议，即杏仁核对将视觉刺激与强化物的激励价值联系起来很重要。
