心算年老化的认知心理机制及功能磁共振成像研究
刘昌
学位类型博士
导师李德明
1998
学位授予单位中国科学院心理研究所
学位授予地点中国科学院心理研究所
学位专业生物心理学
关键词心算 年龄 工作记忆 感觉运动速度 功能磁共振成像 脑激活
摘要应用行为学方法和功能磁共振成像(Functional Magnetic Resonance Imaging, fMRI)技术对心算老化的认知心理及脑生理机制进行了研究。(一)心算加工年老化的认知心理机制研究 被试共172人,20-79岁,身体健康,受教育年限12年以上(1.51 ± 1.5年)。被试任务为连续减法心算,依难度分为5种:1000-1、1000-3、1000-7、1000-13及1000-17。研究变量为心算、年龄、工作记忆和感觉运动速度。研究分为四项:(1)不同难度心算的年老化过程,(2)心算加工年老化机制,(3)工作记忆和感觉运动速度在心算加工年老化过程中的作用,(4)心算加工的认知老化模型。主要采用多元方差分年(MANOVA)、层次多元回归(hierarchical multiple regression)、逐步回升分析(stepwise regression analysis)、结构方程建模(structural equation modelling,SEM)等统计方法。结果如下:研究一:年龄与心算难度存在明显的交互作用,反应时随着年龄增加和心算难度增大而延长,心算效率(正确率与反应时之比)随着年龄增加和心算难度增大而降低;随着年龄增加,不同难度心算效率均以幂函数形式降低;研究二:心算加工年老化过程存在两个中介作用因子(潜变量因子),年龄通过作用于这两个因子而对不同难度水平的心算产生影响;研究三:年龄与工作记忆、工作记忆与心算难度之间均存在明显的交互作用;且工作记忆和感觉运动速度对心算加工的年老化均有影响,工作记忆对不同难度心算年老化的作用量约为30%-50%,感觉运动速度对不同难度心算年老化的作用量大于35%。研究四:年龄、工作记忆和感觉运动速度通过作用于两个潜变量因子而对不同难度的心算产生影响;影响心算加工的潜变量因子1和因子2分别分与记忆成分和速度成分有关,且因子2(速度成分)对因子1(记忆成分)存在显著的正效应。(二)心算加工年老化的功能磁共振成像研究 被试均为右利手,分为青年(20-29岁,7名)和老年(60-69岁,7名)两个年龄组,仪器为Signa Horizon 1.5T超导型磁共振成像系统。实验设计采用“基线(baseline)-任务”的OFF-ON减法模式,任务为2个难度水平的连续减法心算,分别为1000-3和1000-17,并以不断重复地默数1000(即1000-0)作为控制任务。磁共振扫描所得原始数据储存于磁共振成像系统,实验后在SUN SPARC工作站上进行离线式(off-line)分析,软件为国际通用的STIMULATE。统计分析步聚分为被试内分析和被试间分析。被试内分析采用t-test,可得到不同难度心算加工时的脑激活图像;被试间分析主要采用非参数Wilcoxon检验,用于考查不同难度心算加工时的脑激活特点、心算加工时左右脑的关系以及脑活动的年龄特征等。结果表明:(1)心算加工有赖于大脑有关脑区的共同参与,其中顶部皮层(Brodmann 7区、40区)、额上回(6区、8区)、额中回(9区、46区)、额下回(44区)、前扣带回(32区)均参与心算加工;(2)参与心算加工脑区的激活率与心算难度有密切关系,“1000-17…”对各有关脑区的激活率比“1000-3…”更高,但“1000-3…”与“1000-17…”两者的功能磁共振信号强度无明显差别;(3)大脑左半球是心算加工的优势半球,但随着心算难度加大,右脑与左脑激活率之比明显上升,即右脑的作用相对增加;(4)心算加工时青、老年组均表现出上述三项特点,但同时也存在以下差别:老年组部分脑区的激活面积有所扩大;老年组右脑参与的相对程度较青年组低;老年组功能磁共振信号强度明显低于青年组,但心算加工时青、老年组信号强度增大的幅度无明显差别;老年组心算加工潜伏期较青年组长。上述认知心理机制研究结果表明,心算加工需要记忆(如工作记忆)参与,并受信息加工速度的影响,且速度因子作用于记忆因子,从而导致心算效率随增龄以幂函数形式降低。同时fMRI研究揭示出,心算加工需要额叶和顶叶某些脑区的共同参与,其脑激活模式与文献报导的工作记忆脑激活模式极为类似,进一步证明工作记忆与心算加工有密切关系,而心算加工时左右脑的参与程度、功能磁共振信号强度以及血液动力学反应潜伏期存在年龄差异,表明心算行为的年龄差异有其深刻的脑生理基础。
其他摘要Mechanisms underlying cognitive psychology and cerebral physiological of mental arithmetic with increasing are were studied by using behavioral methods and functional magnetic resonance imaging (fMRI). I. Studies on mechanism underlying cognitive psychology of mental arithmetic with increasing age These studies were accomplished in 172 normal subjects ranging from 20 to 79 years of age with above 12 years of education (Mean = 1.51, SD = 1.5). Five mental arithmetic tasks, "1000-1", "1000-3", "1000-7", "1000-13", "1000-17", were designed with a serial calculation in which subjects sequentially subtracted the same prime number (1, 3, 7, 13, 17) from another number 1000. The variables studied were mental arithmetic, age, working memory, and sensory-motor speed, and four studies were conducted: (1) Aging process of mental arithmetic with different difficulties, (2) mechanism of aging of mental arithmetic processing. (3) effects of working memory and sensory-motor speed on aging process of mental arithmetic, (4) model of cognitive aging of mental arithmetic, with statistical methods such as MANOVA, hierarchical multiple regression, stepwise regression analysis, structural equation modelling (SEM). The results were indicated as following: Study 1: There was an obvious interaction between age and mental arithmetic, in which reaction time (RT) increased with advancing age and more difficult mental arithmetic, and mental arithmetic efficiency (the ratio of accuracy to RT) deceased with advancing age and more difficult mental arithmetic; Mental arithmetic efficiency with different difficulties decreased in power function: Study 2: There were two mediators (latent variables) in aging process of mental arithmetic, and age had an effect on mental arithmetic with different difficulties through the two mediators; Study 3: There were obvious interactions between age and working memory, working memory and mental arithmetic; Working memory and sensory-motor speed had effects on aging process of mental arithmetic, in which the effect of working memory on aging process of mental arithmetic was about 30-50%, and the effect of sensory-motor speed on aging process of mental arithmetic was above 35%. Study 4: Age, working memory, and sensory-motor speed had effects on two latent variables (factor 1 and factor 2), then had effects on mental arithmetic with different difficulties through factor 1 which was relative to memory component, and factor 2 which relative to speed component and had an effect on factor 1 significantly. II. Functional magnetic resonance imaging study on metal arithmetic with increasing age This study was accomplished in 14 normal right-handed subjects ranging from 20 to 29 (7 subjects) and 60 to 69 (7 subjects) years of age by using functional magnetic resonance imaging apparatus, a superconductive Signa Horizon 1.5T MRI system. Two mental arithmetic tasks, "1000-3" and "1000-17", were designed with a serial calculation in which subjects sequentially subtracted the same prime number (3 or 17) from another number 1000 silently, and controlling task, "1000-0", in which subjects continually rehearsed number 1000 silently, was regarded as baseline, based on current "baseline-task" OFF-ON subtraction pattern. Original data collected by fMRI apparatus, were analyzed off-line in SUN SPARC working station by using current STIMULATE software. The analytical steps were composed of within-subject analysis, in which brain activated images about mental arithmetic with two difficulties were obtained by using t-test, and between-subject analysis, in which features of brain activation about mental arithmetic with two difficulties, the relationship between left and right hemisphere during mental arithmetic, and age differences of brain activation in young and elderly adults were examined by using non-parameter Wilcoxon test. The results were as following:
页数59
语种中文
文献类型学位论文
条目标识符http://ir.psych.ac.cn/handle/311026/4806
专题中国科学院心理研究所回溯数据库(1956-2010)
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刘昌. 心算年老化的认知心理机制及功能磁共振成像研究[D]. 中国科学院心理研究所. 中国科学院心理研究所,1998.
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