Material-specific lateralization in the medial temporal lobe and prefrontal cortex during memory encoding
Material-specific lateralization in the medial temporal lobe and prefrontal cortex during memory encoding
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DOI：
10.1093/brain/124.9.1841
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发表时间：
2001-09-01
期刊：
影响因子：
14.5
通讯作者：
Gabrieli, JDE
中科院分区：
文献类型：
--
作者：
Golby, AJ;Poldrack, RA;Gabrieli, JDE
在内侧颞叶(MTL)和前额叶皮质单侧病变患者的大量观察表明，记忆过程根据内容被偏侧化。左侧病变干扰言语记忆过程，而右侧病变干扰视觉空间(非言语)记忆过程。然而，功能成像研究得到了相互矛盾的数据，一些研究表明，前额叶皮质的偏侧化由加工阶段(编码与提取)决定，另一些研究表明，偏侧化取决于材料的类型。很少有研究在MTL中研究这一问题。为了验证这样一种假设，即MTL和额叶区域编码过程的偏侧化取决于材料的可言语化，我们进行了行为和功能成像研究。我们使用双任务言语干扰行为范式，展示了三类非语言刺激(场景、面孔和抽象模式)的不同可言语性。使用这三种类型的刺激加上单词，进行了编码的功能神经成像研究。在1.5T全脑功能磁共振成像中，8名正常右利手成年人被呈现在有意记忆编码条件下交替出现的新的和重复的刺激区块。语言编码导致左侧化激活下前额叶皮质和MTL。模式编码激活了右侧额叶下部皮质和右侧MTL。场景和面部在两个区域都产生了大致对称的激活。数据表明，编码过程的偏侧化程度取决于刺激的可言语化程度。
Numerous observations in patients with unilateral lesions of the medial temporal lobe (MTL) and the prefrontal cortex indicate that memory processes are lateralized according to content. Left-sided lesions interfere with verbal memory processes, whereas right-sided lesions interfere with visuospatial (non-verbal) memory processes. However, functional imaging studies have resulted in contradictory data, some studies showing lateralization in the prefrontal cortex determined by stage of processing (encoding versus retrieval) and others suggesting that lateralization is dependent on the type of material. Few studies have examined this issue in the MTL. In order to test the hypothesis that the lateralization of encoding processes in the MTL and frontal regions is dependent on the verbalizability of the material, we performed behavioural and functional imaging studies. We demonstrated differing verbalizabilities of three classes of non-verbal stimuli (scenes > faces > abstract patterns) using a dual-task verbal interference behavioural paradigm. A functional neuroimaging study of encoding was carried out using these three types of stimuli, plus words. During whole-brain functional MRI at 1.5 T, eight normal right-handed adults were presented with alternating blocks of novel and repeated stimuli under intentional memory encoding conditions. Verbal encoding resulted in left-lateralized activation of the inferior prefrontal cortex and the MTL. Pattern encoding activated the right inferior prefrontal cortex and the right MTL. Scenes and faces resulted in approximately symmetrical activation in both regions. The data indicate that the lateralization of encoding processes is determined by the verbalizability of stimuli.