Functional specialization in the human medial temporal lobe
Functional specialization in the human medial temporal lobe
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DOI：
10.1523/jneurosci.2704-05.2005
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发表时间：
2005-11-02
影响因子：
5.3
通讯作者：
Graham, KS
中科院分区：
文献类型：
--
作者：
Barense, MD;Bussey, TJ;Graham, KS
对大鼠和非人类灵长类动物的记忆的研究表明，内侧颞叶（MTL）中有功能专业化，这是一组紧密互连的结构，包括海马形成和基础内hin虫，肠hin虫，周围和副膜状皮质。然而，大多数人类的研究，尤其是在脑损伤患者中，都表明人MTL是一个单一的记忆系统，支持所有类型的声明性记忆，我们对事实和事件的有意识记忆。为了解决这一差异，对具有选择性海马损害或更广泛的MTL损害的失忆症患者进行了根据非人类灵长类动物文献适应的物体歧视任务的变化进行了测试。尽管两组在基于标准的召回内存任务上同样受损，但它们在对象歧视测试上表现出不同的性能概况，反对MTL功能的单一观点。有选择性海马损伤的病例正常执行，而MTL病变更广泛的人受到损害。此外，后一组中的缺陷与要学习和记住的歧视的数量无关，而与“特征歧义”的程度有关，这是视觉区分的属性，当特征既是奖励和未经奖励刺激的特征的一部分时都会出现的。这些发现解决了在人类和动物中发表的研究之间的矛盾，并引入了一种表征MTL损害后出现的障碍的新方法。
Investigations of memory in rats and nonhuman primates have demonstrated functional specialization within the medial temporal lobe (MTL), a set of heavily interconnected structures including the hippocampal formation and underlying entorhinal, perirhinal, and parahippocampal cortices. Most studies in humans, however, especially in patients with brain damage, suggest that the human MTL is a unitary memory system supporting all types of declarative memory, our conscious memory for facts and events. To resolve this discrepancy, amnesic patients with either selective hippocampal damage or more extensive MTL damage were tested on variations of an object discrimination task adapted from the nonhuman primate literature. Although both groups were equally impaired on standard recall-based memory tasks, they exhibited different profiles of performance on the object discrimination test, arguing against a unitary view of MTL function. Cases with selective hippocampal damage performed normally, whereas individuals with broader MTL lesions were impaired. Furthermore, deficits in this latter group were related not to the number of discriminations to be learned and remembered, but to the degree of "feature ambiguity," a property of visual discriminations that can emerge when features are part of both rewarded and unrewarded stimuli. These findings resolve contradictions between published studies in humans and animals and introduce a new way of characterizing the impairments that arise after damage to the MTL.