在记忆过程中额叶与信息粒度的交互作用

Interaction between frontal lobe and information granularity during memory process

采用事件相关的功能磁共振技术(fMRI)研究了记忆与信息粒度的相互关系.实验使用相同的记忆任务-Boolean规则,依据Ebbinghaus范式,要求被试在完全掌握规则后的第1天(短期记忆)和学习训练后的第7天(长期记忆)完成fMRI测试.结果表明,短期记忆任务和长期记忆任务均激活了左侧额下回和额中回,但短期记忆任务相对长期记忆任务激活更多的左侧中央前回和额下小叶、右侧的额上回和额中回,而长期记忆比短期记忆激活了更多的右侧的额下回,这可能与规则中的各个元素之间的聚合程度和记忆的精度有关.因此,额叶对不同信息粒度的规则提取有重要影响.高粒度相对于低粒度的Boolean规则提取需要更短的时间,但是记忆信息提取的正确率不会因高低粒度的不同而表现出差异.虽然信息粒度对长、短期记忆任务的提取的正确率不起决定性作用,但信息粒度作为记忆巩固与否的一种度量标准会对提取时间产生影响;这可能使得规则提取的策略不同,因此,额叶对不同粒度的信息提取起到了至关重要的作用.

This paper studies the relationship between memory and information granularity using event-related functional magnetic resonance imaging technology（fMRI）.Experiment employed the same memory task-Boolean rules,based on Ebbinghaus paradigm,participants are asked to complete the fMRI tests in the first day when they fully grasp the rules and the seventh day after the training or learning.The results show that short-term memory tasks and long-term memory tasks activate the left inferior frontal lobule and left middle frontal gyrus.Simultaneity,the short-term memory tasks activated more brain areas than the long-term memory tasks do（including： left precentral gyrus,the left inferior frontal lobule,right superior frontal gyrus and the right middle frontal gyrus）.The long-term memory tasks activated more right inferior frontal gyrus than the short-term memory tasks.This findings may be because the rules of the linkages between the various elements of the rules is detailed and the accuracy of memory.Right frontal lobe has a major impact on the extract of the rules of different information granularity.High-granularity,with respect to the low granularity of Boolean rule extraction,requires a shorter time,but the correct rate of the memory information extraction will not be different because of the different performance of different level of granularity.Although the information of granule size on the extraction of short and long term memory tasks doesn＇t play a decisive role in the correct rate,the information granularity,as a measure of whether or not memory consolidation,will have an impact on extraction time;this rule may result in different strategy of extraction.Therefore,parietal lobe plays a crucial role in the information extraction of different granularity.