Murray E A, Gaffan D, Mishkin M
Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, Maryland 20892.
J Neurosci. 1993 Oct;13(10):4549-61. doi: 10.1523/JNEUROSCI.13-10-04549.1993.
Rhesus monkeys learned 10 visual stimulus-stimulus association, or paired associates. They then received bilateral removals of either the amygdaloid complex and underlying cortex, the hippocampal formation and underlying cortex, or both combined, or they were retained as unoperated controls. After surgery or rest, the monkeys were tested for their retention of the preoperatively learned set of paired associates, as well as for their ability to learn new associations of the same type. Both unoperated controls and hippocampectomized monkeys relearned the preoperatively trained set of paired associates almost immediately. By contrast, monkeys with amygdala removals were moderately retarded in relearning, and monkeys with combined amygdala and hippocampal ablations were severely retarded. When confronted with new sets of visual stimuli, monkeys with amygdala removals or hippocampal removals learned new sets of paired associates at the same rate as the controls, whereas monkeys with the combined ablation were again profoundly retarded. Only one monkey with the combined lesion was able to learn new stimulus-stimulus associations to criterion, and then only after extensive training, despite the ability of all three animals in this group to perform delayed matching-to-sample with the same stimuli and the same intraatrial delays as those used in the paired associate task. At the end of the main experiment, two of the unoperated controls received bilateral ablations of the rhinal cortex. These monkeys showed the same level of difficulty in learning new paired associates as the animals in the main experiment that had received the combined amygdala plus hippocampal ablations. The results implicate the medial temporal lobe, and particularly the rhinal cortex, in the formation of stimulus-stimulus associative memories.
恒河猴学会了10种视觉刺激-刺激关联，即配对联想。然后，它们接受了双侧杏仁复合体及其下方皮质、海马结构及其下方皮质的切除，或者两者联合切除，或者作为未手术的对照保留下来。手术后或休息后，对猴子进行测试，以检查它们对术前学习的配对联想组的记忆保持情况，以及学习相同类型新联想的能力。未手术的对照猴子和海马切除的猴子几乎立即重新学会了术前训练的配对联想组。相比之下，杏仁核切除的猴子重新学习的速度中等程度地减慢，而杏仁核和海马联合切除的猴子则严重减慢。当面对新的视觉刺激组时，杏仁核切除或海马切除的猴子学习新的配对联想组的速度与对照组相同，而联合切除的猴子再次严重减慢。只有一只联合损伤的猴子能够学会新的刺激-刺激关联达到标准，而且只有在经过广泛训练后才行，尽管该组的所有三只动物都有能力用与配对联想任务中相同的刺激和相同的房内延迟进行延迟匹配样本任务。在主要实验结束时，两只未手术的对照猴子接受了双侧嗅皮质切除。这些猴子在学习新的配对联想时表现出的困难程度与主要实验中接受杏仁核加海马联合切除的动物相同。结果表明内侧颞叶，特别是嗅皮质，在刺激-刺激联想记忆的形成中起作用。
