Brain activity during memory retrieval - The influence of imagery and semantic cueing
Brain activity during memory retrieval - The influence of imagery and semantic cueing
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DOI：
10.1093/brain/119.5.1587
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发表时间：
1996-10-01
期刊：
影响因子：
14.5
通讯作者：
Dolan, RJ
中科院分区：
文献类型：
--
作者：
Fletcher, PC;Shallice, T;Dolan, RJ
通过对健康志愿者的功能成像研究，探讨了意象和语义关联对线索词对检索的影响。受试者接受了12次PET扫描，之前有12对同伴的节奏展示。同伙被分为可想象组和不可想象组。在每一组中，对成员之间的语义关联强度按顺序变化。随后，当受试者被提示每对中的第一个项目并被要求回忆相关单词时，测量了神经活动。与不可想象的单词相比，可想象单词的回忆与楔前叶的激活有关，这与我们的假设一致，即该区域在情景检索的视觉意象中很重要。相反的对比，不可想象和可想象的回忆，与左背外侧前额叶皮层的激活有关。在可想象组和不可想象组中，语义关联的减少表明双侧额叶活动相应增加。一种可能的解释是，这是一种与练习相关的效应，连接较弱的配对在扫描前有更多的表现。然而，这种解释是不完整的，因为语义上距离最远、排练最多的配对（随机连接）与这种效应的逆转有关。如果额叶活动与在检索时消除不适当反应的难度有关，这一发现可以得到解释。我们的研究结果表明，在线索回忆过程中，神经活动的模式取决于材料的性质以及线索和反应之间的关联程度，因此，消除错误反应的工作将更加艰巨。
The effects of imagery and semantic relatedness on cued retrieval of word pairs were examined in a functional imaging study of healthy volunteers. Subjects underwent 12 PET scans, preceded by the paced presentation of 12 paired associates. The associates were dichotomized into imageable and non-imageable groups. Within each group, the strength of semantic association between members of pairs was varied in an ordinal fashion. Subsequently, neural activity was measured while subjects were cued with the first item of each pair and required to recall the associated word. Recall of imageable words, when compared with non-imageable ones, was associated with activation of the precuneus, consistent with our hypothesis that this region is important in visual imagery at episodic retrieval. The reverse comparison, non-imageable versus imageable recall, was associated with activation of the left dorsolateral prefrontal cortex. Within both imageable and non-imageable groups, decreasing semantic association showed a corresponding increase in frontal activity bilaterally. One possible explanation is that of a practice-related effect, weaker-linked pairs having a greater number of pre-scan presentations. However this explanation is incomplete as the most semantically distant, and most rehearsed, pairs (randomly linked) were associated with a reversal of this effect. This finding can be explained if frontal activity is associated with the difficulty of eliminating inappropriate responses at retrieval. For both randomly linked pairs and closely related pairs it is more likely that erroneous responses will be generated and, therefore, the work done to eliminate them will be greater Our findings indicate that patterns of neural activity during cued recall depend upon the nature of the material and on the degree of association between the cue and the response.