时间认知的脑机制研究

从神经心理学和脑成像2个领域综述了有关时间认知脑机制的研究。神经心理学及脑损伤的研究结果表明小脑可能与内部时钟功能有关,前额叶可能调节时间认知中的注意过程。PET和fMRI脑成象研究结果显示,基底神经节、小脑和前额叶在所有的计时作业中都被激活。ERP的研究结果还证实,时间信息加工和非时间信息加工存在时间历程上的差异,并且时间信息加工还存在的显著半球优势效应。因此基底神经节、小脑和前额叶可能是时间认知的主要脑机制,但由于研究材料、方法和程序的不同,大脑皮层的广泛区域都有可能参与时间信息的加工。     

社会互动视角下人际公平形成的脑机制

最后通牒博弈任务被广泛用以探究公平行为, 以往研究大多集中于对博弈中某一方决策行为和神经机制的探讨, 但是人际公平可能是互动双方重复博弈的结果。因此只考察单个大脑活动, 并不足以揭示由互动双方共同完成的社会认知活动的脑机制。因此, 本研究结合修改版的最后通牒博弈任务和基于fNIRS的超扫描技术, 从群体脑水平上考察人际公平形成的脑机制。行为结果显示, 相比无惩罚条件, 惩罚下提议者的分配金额更高, 且惩罚力度越强, 分配越趋近公平分配。fNIRS的结果显示, 惩罚下右侧背外侧前额叶皮层、顶下小叶和颞-顶联合区的脑间活动同步性显著强于无惩罚条件, 而且两条件的分配金额差异越大, 右侧顶下小叶的脑间活动同步性差异也越大。综上, 脑间活动同步性可以作为惩罚下人际公平形成的客观脑指标, 研究为探讨人际公平的内在机制提供了新的视角。     

时间认知神经科学研究进展

当前对时间认知的脑机制探讨有三个模型：特异化计时模型、分布网络模型和定域计时模型。在这些模型的框架下,时间认知的神经心理学研究集中探讨了小脑、基底神经节、前额叶在时间信息加工中的作用和大脑两半球在时间认知中的不对称性。小脑作为内部计时系统对时间控制具有重要作用,在周期性动作任务中,小脑对不连续动作计时具有特异性。基底神经节在时间加工任务中与小脑存在明显的作用分离,其具体机制还有待深入研究。前额叶的计时功能可能与注意和工作记忆对时间信息的获得、维持和组织有关。此外,还发现大脑右半球与时问信息的加工关系密切。     

音乐绝对音高信息加工的脑机制

音乐绝对音高(absolute pitch, AP)一直是音乐心理学者感兴趣的问题。AP能力是一种特殊的音乐能力。ERP研究表明具有AP能力的群体只需较少的认知资源进行音高加工, 同时不同AP能力的加工机制也不同; 功能神经成像研究表明大脑左侧额叶背侧后部和左侧颞叶平面对AP加工发挥重要作用; 脑结构研究发现AP群体的某些脑区皮层厚度低于没有绝对音高能力(Non-AP)群体, 这可能与AP特殊的加工机制有关。AP能力形成需要先天遗传和后天环境的共同作用, 其相互作用的脑机制需结合行为遗传学的研究方法及成果。     

左前额叶与趋近动机加工的关系

在加工正性情绪时, 前额叶左侧激活水平大于右侧。而正性情绪往往伴随着趋近动机。因此为了探索这种现象反映的究竟是正性情绪加工还是趋近动机加工, 文章总结了两个研究领域中的有关证据：来自特质或状态愤怒情绪与左前额叶相对激活关系领域的研究证据和来自身体姿势变化(包括整体姿势变化和单侧肌肉紧缩)对左前额叶相对激活的影响领域的研究证据。前者的一致发现是：左前额叶参与加工由愤怒情绪引发的趋近动机。后者的一致发现是：不同的身体姿势能够改变左前额叶的相对激活水平。两种领域的研究证据汇聚起来证明左前额叶参与加工趋近动机。文章还指出了将来研究的注意事项和可能方向：精确定义回避型愤怒; 探索愤怒情绪是否在加工晚期诱发趋近或回避动机; 探索不同方式诱发的趋近动机是否在脑机制上存在差异。     

前额叶在记忆中的作用──脑功能成像研究进展

以往采用动物实验和神经心理学的研究表明,前额叶与记忆功能有着密切的关系。采用脑功能成像 技术的研究使我们对前额叶在记忆中的作用有了更深的认识。左前额叶主要参与情节记忆的编码和 语义性启动效应,右前额叶则与情节记忆的提取关系密切。另外,前额叶还是工作记忆的神经基础, 尤其是背外侧前额叶。     

左侧前额叶语言加工功能研究综述

1 引言 探讨左前额叶的认知功能是目前脑成像研究的焦点之一。前额叶皮层占人类大脑的1/3。70年代初,鲁利亚提出大脑的三个机能系统时认为,额叶属于第三机能系统,负责编制行为程序,调节、控制行为,它对于完成很多高级认知加工,如计划、控制、问题解决等有着重要作用。近年来不断有研究发现,左侧前额叶还参与了许多和语言加工有关的活动,特别是额下回、Broca区等大脑区域被研究者进行了广泛地探讨。     

寻找自我:基于认知神经的观点

默认网络相关研究表明,生物进化的社会适应性建构了自我的认知神经基础,与James的自我结构相对应:主我位于后部扣带回,精神自我位于内侧前额叶,身体自我位于顶下小叶和脑岛; 并且与内侧前额叶、顶下小叶和后部扣带回之间的信息传递相关。个体在基线水平的大脑活动表明,自我是通过后部扣带回接收并调节全脑(包括表征客我的脑区)信息流,随时准备将外界满足需要有利于个体生存的资源纳入其中的神经系统。对于探讨“认识自我”这个古老的哲学问题与现代认知神经科学之间的关系有重要意义。     

冲突适应过程中的神经信息传递机制

在认知控制研究领域中,冲突适应(conflict adaptation)涉及大脑对冲突进行连续的认知调整,它能反映人类有效控制冲突的基本机制。然而,现有研究还没有充分地揭示冲突适应的脑机制。本研究通过对被试完成字母Flanker任务时的脑电(electroencepihalography,EEG)数据进行有效连通性分析,揭示了冲突适应过程中的神经信息传递机制。在观察任务中,当大脑传递冲突信号时,从左前额叶电极点到中前区电极点的连通性(β频带:20~21 Hz,400~650 ms)增强,以使大脑顺利完成与反应抑制相关的加工;在反应任务中,从中前区电极点到右前额叶电极点,congruency-Congruency条件比incongruency-Congruency条件的连通性(β频带:18~21 Hz,600~1,000 ms)更强。这些结果共同说明β频带的活性调整过程反映了大脑有效的执行控制过程,从而在行为上表现出由冲突观察所诱发的冲突适应。     

信息保持、短时存贮与执行控制的脑模型

工作记忆的脑机制是认知神经科学研究的重要问题。研究者在分析大量脑成像研究数据的基础上,创建了许多解释工作记忆神经基础的模型。Smith和Jonides发展了工作记忆成分结构模型和贮存与执行加工分离模型。Postle和D’Esposito建构了工作记忆相对表征混合模型,D’Esposito, Postle和Rypma阐述了工作记忆加工阶段动态模型。Fletcher和Henson提出工作记忆额叶分区整合理论。该文通过对上述模型或理论的评价,总结了工作记忆脑成像研究中存在的问题,展望了该研究领域的发展趋势。     

押韵加工的认知神经机制

押韵是指一对词语中从最后一个发音的元音到词尾的语音结构均相同的现象。现有押韵加工主要分为押韵识别与押韵产生两个研究领域,两者的认知加工过程相似,包括字形编码、形音转换、语音表征与语音分段等阶段。从语音加工与字形加工两方面对押韵过程的神经基础进行探讨,发现左半球颞上回与额下回分别负责语音表征与语音分段,左半球梭状回参与着字形编码,而有效的形音转换依赖于左半球顶下小叶与额下回组成的神经网络。今后应进一步整合不同研究方法与任务下的研究结果,并对押韵产生加工进行更深入的探讨。     

Effective brain connectivity in children with reading difficulties during phonological processing

Using Dynamic Causal Modeling (DCM) and functional magnetic resonance imaging (fMRI), we examined effective connectivity between three left hemisphere brain regions (inferior frontal gyrus, inferior parietal lobule, fusiform gyrus) and bilateral medial frontal gyrus in 12 children with reading difficulties (M age=12.4, range: 8.11-14.10) and 12 control children (M age=12.3, range: 8.9-14.11) during rhyming judgments to visually presented words. More difficult conflicting trials either had similar orthography but different phonology (e.g. pint-mint) or similar phonology but different orthography (e.g. jazz-has). Easier non-conflicting trials had similar orthography and phonology (e.g. dime-lime) or different orthography and phonology (e.g. staff-gain). The modulatory effect from left fusiform gyrus to left inferior parietal lobule was stronger in controls than in children with reading difficulties only for conflicting trials. Modulatory effects from left fusiform gyrus and left inferior parietal lobule to left inferior frontal gyrus were stronger for conflicting trials than for non-conflicting trials only in control children but not in children with reading difficulties. Modulatory effects from left inferior frontal gyrus to inferior parietal lobule, from medial frontal gyrus to left inferior parietal lobule, and from left inferior parietal lobule to medial frontal gyrus were positively correlated with reading skill only in control children. These findings suggest that children with reading difficulties have deficits in integrating orthography and phonology utilizing left inferior parietal lobule, and in engaging phonological rehearsal/segmentation utilizing left inferior frontal gyrus possibly through the indirect pathway connecting posterior to anterior language processing regions, especially when the orthographic and phonological information is conflicting.     

Neural correlates of arithmetic calculation strategies

Recent research into math cognition has identified areas of the brain that are involved in number processing (Dehaene, Piazza, Pinel, & Cohen, 2003) and complex problem solving (Anderson, 2007). Much of this research assumes that participants use a single strategy; yet, behavioral research finds that people use a variety of strategies (LeFevre et al., 1996; Siegler, 1987; Siegler & Lemaire, 1997). In the present study, we examined cortical activation as a function of two different calculation strategies for mentally solving multidigit multiplication problems. The school strategy, equivalent to long multiplication, involves working from right to left. The expert strategy, used by “lightning” mental calculators (Staszewski, 1988), proceeds from left to right. The two strategies require essentially the same calculations, but have different working memory demands (the school strategy incurs greater demands). The school strategy produced significantly greater early activity in areas involved in attentional aspects of number processing (posterior superior parietal lobule, PSPL) and mental representation (posterior parietal cortex, PPC), but not in a numerical magnitude area (horizontal intraparietal sulcus, HIPS) or a semantic memory retrieval area (lateral inferior prefrontal cortex, LIPFC). An ACT-R model of the task successfully predicted BOLD responses in PPC and LIPFC, as well as in PSPL and HIPS.     

音乐表演训练对神经可塑性的影响:元分析研究

音乐表演是人类最复杂和精细的技能之一。通过激活似然性评估元分析,对音乐表演训练所诱发的神经可塑性进行探究。结果发现,音乐表演者与非音乐家在左侧小脑、双侧中央前回、双侧颞上回、左侧额下回、双侧顶下小叶以及右侧脑岛等脑区存在差异。这些脑区与听觉、运动以及多通道信息整合等加工有关。未来研究应从不同音乐表演训练诱发的神经适应性出发,进一步探究音乐表演训练与大脑可塑性之间的关联。     

Increased arithmetic complexity is associated with domain-general but not domain-specific magnitude processing in children: A simultaneous fNIRS-EEG study

The investigation of the neural underpinnings of increased arithmetic complexity in children is essential for developing educational and therapeutic approaches and might provide novel measures to assess the effects of interventions. Although a few studies in adults and children have revealed the activation of bilateral brain regions during more complex calculations, little is known about children. We investigated 24 children undergoing one-digit and two-digit multiplication tasks while simultaneously recording functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) data. FNIRS data indicated that one-digit multiplication was associated with brain activity in the left superior parietal lobule (SPL) and intraparietal sulcus (IPS) extending to the left motor area, and two-digit multiplication was associated with activity in bilateral SPL, IPS, middle frontal gyrus (MFG), left inferior parietal lobule (IPL), and motor areas. Oscillatory EEG data indicated theta increase and alpha decrease in parieto-occipital sites for both one-digit and two-digit multiplication. The contrast of two-digit versus one-digit multiplication yielded greater activity in right MFG and greater theta increase in frontocentral sites. Activation in frontal areas and theta band data jointly indicate additional domain-general cognitive control and working memory demands for heightened arithmetic complexity in children. The similarity in parietal activation between conditions suggests that children rely on domain-specific magnitude processing not only for two-digit but—in contrast to adults—also for one-digit multiplication problem solving. We conclude that in children, increased arithmetic complexity tested in an ecologically valid setting is associated with domain-general processes but not with alteration of domain-specific magnitude processing.     

Generating animal and tool names: an fMRI study of effective connectivity

The present fMRI study of semantic fluency for animal and tool names provides further evidence for category-specific brain activations, and reports task-related changes in effective connectivity among defined cerebral regions. Two partially segregated systems of functional integration were highlighted: the tool condition was associated with an enhancement of connectivity within left hemispheric regions, including the inferior prefrontal and premotor cortex, the inferior parietal lobule and the temporo-occipital junction; the animal condition was associated with greater coupling among left visual associative regions. These category-specific functional differences extend the evidence for anatomical specialization to lexical search tasks, and provide for the first time evidence of category-specific patterns of functional integration in word-retrieval.     

Suppression of brain activity related to a car-following task with an auditory task: An fMRI study

Driving a car in daily life involves multiple tasks. One important task for safe driving is car-following, the interference of which causes rear-end collisions: the most common type of car accident. Recent reports have described that car-following is hindered even by hands-free mobile telephones. We conducted functional MRI with 18 normal volunteers to investigate brain activity changes that occur during a car-following task with a concurrent auditory task. Participants performed three tasks: a driving task, an auditory task, and a dual task in an fMRI run. During the driving task, participants use a joystick to control their vehicle speed in a driving simulator to maintain a constant distance from a leading car, which moves at varying speed. Language trials and tone discrimination trials are presented during the auditory task. Car-following performance was worse during the dual task than during the single-driving task, showing positive correlation with brain activity in the bilateral lateral occipital complex and the right inferior parietal lobule. In the medial prefrontal cortex and left superior occipital gyrus, the brain activity of the dual task condition was less than that in the single-driving task condition. These results suggest that the decline of brain activity in these regions may induce car-following performance deterioration.     

双语控制的神经基础及其对第二语言教学的启示

双语加工和控制的认知神经科学研究发现,与一般性执行功能有关的最关键的脑区前额皮层,以及其它的相关脑区及神经基础如前扣带回、基底神经节和下顶叶等参与了双语语言理解和语言产生的双语控制中。这些研究成果对于利用第二语言促进认知控制能力的发展,以及利用认知控制训练促进高效率的第二语言教学有着重要的启示。     

计算的脑科学研究及其对数学教育的启示

脑科学研究发现,简单心算主要涉及算术事实的提取,依赖于左半球的语言中枢,而复杂心算激活了左侧顶—额叶网络和双侧颞下回,与视觉空间表征和视觉表象加工有关;精算主要激活左额叶下部区域,而估算激活了两半球更大的区域。在计算过程中所激活的脑区受年龄发展与个体差异以及训练的影响。研究对有效地促进儿童计算能力的发展提供了重要启示。