时序记忆检索的事件相关电位研究

The retrieval of temporal order：an ERP research

目的利用事件相关电位（event—relatedpotentials，ERP）时空模式探讨时序记忆信息检索的神经机制。方法17名青年学生参与实验。基于Steinberg范式，在编码维持期系列呈现四个不同颜色的项目一圆形；在记忆检索期，被试针对呈现的一对探针图形、须分别完成项目时序判断（时序包含三种间隔）、新旧项目再认判断及几何图形辨别三种任务。应用单因素三水平重复测量方差分析和配对比较，分析了记忆检索期的行为绩效和19通道ERP。结果时序间隔因素的行为绩效差异有显著性：反应时间分别为（745．5±106．1）ms，（711．7±102．2）ms，（653．7±81．5）ms；（F（1.28,20.48）=43．37，P=0．00）。正确率分别为（62．85-7．0）％，（72．5±5．4）％，（84．5±6．4）％；Ff2Ⅲ=132．60，P=0．00。项目间隔越近，反应时间越长，正确率越低。任务因素行为绩效亦显著：反应时间[F（1.32,21.11）=135．99，P=0．00]及正确率[F（2.32）=200．31，P=0．00]，但时序记忆组与项目再认组的行为绩效差异无显著性。ERP统计参数映射提示时序记忆间隔效应起始于左颞（260～270ms）和双侧顶枕区（280～290ms），突出呈现在双侧顶叶（300～400ms）；时序记忆与再认记忆均涉及双侧半球的广泛区域，但两者比较未见ERP效应。结论在时序记忆检索阶段，时序间隔的距离效应的神经相关主要存在于双侧顶叶；时序信息的检索同客体信息一样，涉及双侧半球的广泛区域。

Objective To investigate neural correlates of the retrieval of temporal order. Methods ERP of 19 channels was recorded from 17 heahhy young students while they performed a recency judgment task, a recognition task and a visual discrimination task separately, which were based on Stenlberg paradigm. One-way ANO- VA of repeated-measurement and post-hoc paired comparisons were carried out for both the task factor （ temporal order, recognition and control） and the temporal distance factor correspondingly. The latter contains 3 intervals （ 1, 2 and 3） between the targets. Results The temporal distance effect was significant ： the closer targets correspond to longer reaction time （ （ 745.5 ± 106. 1 ） ms, （ 711.7 ± 102.2 ） ms, （ 653.7 ± 81.5 ） ms ; F（ 1.28,20.48） = 43.37, P=0.00] and higher error rate（ （62.8 ±7.0）%,（72.5±5.4）%,（84.5 ±6.4）%; F（l.22,21.11） = 135.99, P = 0. 00 ]. Significant behavioral effect of the task factor was also found for both reaction time （F （1.32,21 11 ） = 135.99, P = 0.00） and error rate （F（2.32） = 200. 31, P = 0.00 ）. No significant behavioral difference was found between the temporal order group and the recognition group. The spatiotemporal pattern of statistical parametric mapping （SPM） suggested the ERP effects of temporal order were presented in left temporal region （ 260 - 270 ms） , bilateral parietal-occipital areas （ 280 - 290 ms） , and bilateral parietal lobes （ 300 - 400 ms ） prominently. No ERP effect was found between the temporal order task and the recognition task. Conclusions The neural correlates of the temporal distance effect exist in bilateral parietal regions. Temporal order as well as object information processing involves similar cerebral regions during the retrieval period.