【作者】 周梅花；

【导师】 刘爱伦；

【作者基本信息】 浙江大学 ， 基础心理学， 2006， 硕士

【摘要】 本研究以汉字词为刺激材料,采用两个再认实验来研究不同因素对短时记忆提取成功性的影响程度,并通过运用血氧水平依赖性磁共振脑功能成像技术(fMRI技术),研究不同提取成功条件下,正常人大脑皮层激活情况,进而探讨人类记忆提取的神经机制。 行为学结果:实验1通过操纵提取阶段的再认密度来研究其对提取成功的影响,结果发现,再认密度对提取成功存在显著的影响,高再认密度条件下汉字词的提取成功明显高于低再认密度条件。实验2通过控制编码阶段的学习程度来研究其对提取成功的影响,结果发现,学习程度对汉字词的提取成功存在显著的影响,学习程度越高,提取成功也越高。相对而言,不同学习程度所导致的提取成功的差异更显著。 脑成像结果:汉字词提取过程主要的激活脑区包括前额叶、内侧颞叶、前扣带回、前楔叶、旁海马、岛叶、前中央回、颞上回等区域。 实验1的结果表明,不同提取成功条件下fMRI激活脑区的特征上有很大的相似性。共同的激活脑区包括:双侧额下回(BA47)、左侧额上回(BA9)、双侧额中回(BA46)、左腹侧额叶(BA45)、左内侧额叶(BA8)、双侧内侧颞叶(BA19)、双侧前楔叶(BA31)、双侧旁海马(BA36)、左前扣带回(BA32)、左前中央回(BA6)、左岛叶(BA13)等。不同的激活脑区,相比低提取成功条件,高提取成功条件未明显激活的脑区包括双侧颞上回(BA22)、右额上回(BA9)、右前中央回(BA6)、右内侧额叶(BA8)等。 实验2的结果表明,主要的激活脑区包括前额叶、内侧颞叶、前扣带回、前楔叶、旁海马、岛叶、前中央回、颞上回等区域。两种提取成功条件下共同的激活脑区包括:双侧额下回(BA47)、双侧额上回(BA9)、双侧额中回(BA46)、右侧额上回(BA10)、左内侧额叶(BA8)、左腹侧额叶(BA45)、右内侧颞叶(BA19)、双侧前楔叶(BA31)、双侧旁海马(BA36)、左前扣带回(BA32)、左前中央回(BA6)、双侧岛叶(BA13)、左侧颞上回(BA22)等。不同的激活脑区包括:低提取成功条件下未明显激活的脑区是左额上回(BA10)、右内侧额叶(BA8)、右腹侧额叶(BA45)等;高提取成功条件下未明显激活的脑区是右前中央回(BA6)和右颞上回(BA22)。 综合两个实验的结果,研究者认为汉字词提取是双侧前额叶共同作用的结果,对于提取成功而言,右侧前额叶的优势更明显,尤其是前部和背外侧部对提取成功更敏感。更多还原

【Abstract】 In this study two recognition experiments were designed to explore how different factors affected retrieval success in short-term memory by using Chinese words as materials. Further we employed Blood Oxygenation-Level dependent functional MRI (fMRI) to index neural activity in cerebra cortex according to different condition of retrieval success in order to discuss neural mechanism of human memory.The first experiment tested the effectiveness of recognition density on retrieval success during retrieve stage and the second one tested the effect of learning density on retrieval success during code stage. The main findings of behavioral results were as follows: both recognition density and learning density showed a significant effect on retrieval success. The differences of retrieval success made by learning density were more remarkable.The main findings of functional neuro-imaging results were as follows: retrieval process of Chinese words was associated with increased activity in prefrontal cortex, medial temporal lobe, anterior cingular cortex, precuneus, parahippocampal cortex, insula, superior temporal cortex and so on.In experiment 1, results revealed similar pattern of activation across varying levels of retrieval success. Retrieval success-associated activation were as follows: left and right inferior prefrontal cortex (BA47), left superior prefrontal cortex (BA9), left and right middle prefrontal cortex (BA46), left ventro-prefrontal cortex (BA45), left medial prefrontal cortex (BA8), left and right medial temporal lobe (BA19), left and right precuneus (BA31), left and right Parahippocampal cortex (BA36), left Anterior Cingular Cortex (BA32), left precentral cortex (BA6) and left Insula (BA13).Relative to the low density condition, to a lesser extent, high-density recognition was associated with left and right superior medial temporal cortex (BA22), right superior prefrontal cortex (BA9), right precentral cortex (BA6) and right medial temporal lobe (BA8).In experiment 2, activation across multiple levels of retrieval success were demonstrated as follows: left and right inferior prefrontal cortex (BA47), left and rightsuperior prefrontal cortex (BA9), left and right middle prefrontal cortex (BA46), right superior prefrontal cortex (BA10), left medial prefrontal cortex (BA8), left ventro-prefrontal cortex (BA45), right medial temporal lobe (BA19), left and right precuneus (BA31), left and right parahippocampal cortex (BA36), left anterior cingular cortex (BA32), left precentral cortex (BA6), left and right insula (BA13) and right superior temporal cortex (BA22).The activation of left superior prefrontal cortex (BA10), right medial prefrontal cortex (BA8) and right ventro-prefrontal cortex (BA45) could reflect processes associated with high retrieval success compared by low retrieval success. Contrarily left superior temporal cortex (BA22) and left precentral cortex (BA6) reflected greater activity in low retrieval success.It was suggested left and right prefrontal cortex reflected retrieval process of Chinese words. The findings were consistent with the proposal that activation of right prefrontal cortex played an important role in retrieval success, especially its anterior and dorsolateral cortex were more sensitive to retrieval success.更多还原