汉语单字词音、义加工的脑激活模式

目的：研究汉字音、义加工的脑机制。方法：采用汉字单字词为实验材料，通过功能磁共振成像扫描执行语音和语义两种认知任务的脑区。结果：语音任务激活的脑区有，左侧顶叶下部和颞上回(BA 40／39／22，BA：Brodmann Area，即布鲁德曼分区，下同)，左侧枕中回(BA18／19)，右侧枕下回(BA18／19)，以及左中央前回(BA6)。语义任务激活的脑区有，左侧顶叶下部(BA40／39)和左侧颞上回(BA22)，左侧额下回(BA10／47)，右侧额中回和额上回(BA10／11)，以及左侧额中回(BA11)。语义任务减去语音任务激活的脑区有，左侧额下回(BA47)，左侧海马(BA36)和右侧海马旁回(BA36)。语音任务减去语义任务没有发现任何脑区的显著激活。结论：在语义任务中与语音有关的脑区得到激活；而在语音任务中与语义有关的脑区没有激活。     

Mixed lateralization of phonological assembly in developmental dyslexia

Developmental phonological dyslexia has been characterized as a deficit in phonological assembly. At a neural level, it is possible that this deficit is represented by weak connectivity between anterior and posterior language systems in the left hemisphere. This study used 3-Tesla functional magnetic resonance imaging to investigate phonological assembly in a developmental phonological dyslexic. The phonological dyslexic showed increased activation in the left hemisphere of the inferior frontal gyrus (BA 44/6) and increased activation in the right hemisphere of the parietal cortex (BA 7), occipital cortex (BA 18), and in the cerebellum, as phonological demands were systematically increased. Converging evidence suggests that the core dysfunction in phonological dyslexia resides in and around the angular gyrus of the left hemisphere. This study supports the compensatory role of posterior regions in the right hemisphere together with the left inferior frontal gyrus.     

Acupuncture at the Taixi （KI3） acupoint activates cerebral neurons in elderly patients with mild cognitive impairment

Our previous ifndings have demonstrated that acupuncture at the Taixi （KI3） acupoint in healthy youths can activate neurons in cognitive-related cerebral cortex. Here, we investigated whether acupuncture at this acupoint in elderly patients with mild cognitive impairment can also activate neurons in these regions. Resting state and task-related functional magnetic resonance imaging showed that the pinprick senstation of acupuncture at the Taixi acupoint differed signiifcantly between elderly patients with mild cognitive impairment and healthy elderly controls. Results showed that 20 brain regions were activated in both groups of participants, including the bi-lateral anterior cingulate gyrus （Brodmann areas [BA] 32, 24）, left medial frontal cortex （BA 9, 10, 11）, left cuneus （BA 19）, left middle frontal gyrus （BA 11）, left lingual gyrus （BA 18）, right medial frontal gyrus （BA 11）, bilateral inferior frontal gyrus （BA 47）, left superior frontal gyrus （BA11）, right cuneus （BA 19, 18）, right superior temporal gyrus （BA 38）, left subcallosal gyrus （BA 47）, bilateral precuneus （BA 19）, right medial frontal gyrus （BA 10）, right superior frontal （BA 11）, left cingulate gyrus （BA 32）, left precentral gyrus （BA 6）, and right fusiform gyrus （BA 19）. These results suggest that acupuncture at the Taixi acupoint in elderly patients with mild cogni-tive impairment can also activate some brain regions.     

Error-related brain activation during a Go/NoGo response inhibition task

Inhibitory control and performance monitoring are critical executive functions of the human brain. Lesion and imaging studies have shown that the inferior frontal cortex plays an important role in inhibition of inappropriate response. In contrast, specific brain areas involved in error processing and their relation to those implicated in inhibitory control processes are unknown. In this study, we used a random effects model to investigate error-related brain activity associated with failure to inhibit response during a Go/NoGo task. Error-related brain activation was observed in the rostral aspect of the right anterior cingulate (BA 24/32) and adjoining medial prefrontal cortex, the left and right insular cortex and adjoining frontal operculum (BA 47) and left precuneus/posterior cingulate (BA 7/31/29). Brain activation related to response inhibition and competition was observed bilaterally in the dorsolateral prefrontal cortex (BA 9/46), pars triangularis region of the inferior frontal cortex (BA 45/47), premotor cortex (BA 6), inferior parietal lobule (BA 39), lingual gyrus and the caudate, as well as in the right dorsal anterior cingulate cortex (BA 24). These findings provide evidence for a distributed error processing system in the human brain that overlaps partially, but not completely, with brain regions involved in response inhibition and competition. In particular, the rostal anterior cingulate and posterior cingulate/precuneus as well as the left and right anterior insular cortex were activated only during error processing, but not during response competition, inhibition, selection, or execution. Our results also suggest that the brain regions involved in the error processing system overlap with brain areas implicated in the formulation and execution of articulatory plans.     

Neural correlates of the “Aha” experiences: Evidence from an fMRI study of insight problem solving

In the present study, we used learning-testing paradigm to examine brain activation of “Aha” effects with event-related functional magnetic resonance imaging (fMRI) during solving Chinese logogriphs. Blood oxygenation level-dependent fMRI contrasts between Aha and No-aha conditions were measured. Increased activities in the precuneus (BA 19/7), the left inferior/middle frontal gyrus (BA 9/6), the inferior occipital gyrus (BA 18), and the cerebellum were specifically associated with the “Aha” effects. The results indicate that (1) the precuneus might be involved in successful prototype events retrieval, (2) the left inferior frontal/middle frontal gyrus might be involved in forming novel association and breaking mental sets, (3) the inferior occipital gyrus and the cerebellum might be involved in re-arrangement of visual stimulus and deployment of attentional resources.     

Activation of right fronto-temporal cortex characterizes the 'living' category in semantic processing.

It is a vital ability for humans to distinguish between living and non-living objects. Whether the semantic features of these two classes of objects are represented in distinct brain areas, is unknown. In our study, words belonging to the categories 'living' and 'non-living' were presented visually to twelve right-handed volunteers, while brain activation was measured with event-related fMRI. Subjects had to judge whether the item belonged to one of these categories. Common areas of activation (P<0.05, corrected) during processing of both categories include the inferior occipital gyri bilaterally (BA 17/18), left inferior frontal gyrus (BA 44/45) and left inferior parietal lobe (BA 40). During processing of 'living' minus 'non-living' items, signal changes (P<0.05, corrected) were present in the the right inferior frontal (BA 47), middle temporal (BA 21) and fusiform gyrus (BA 19). Our results are in line with findings from patients with a deficit in semantic processing of living things, who specifically suffer from right hemispheric lesions.     

偏头痛与静息态脑功能连接研究

目的本文研究采用静息态功能磁共振成像(rfMRI)技术描述偏头痛患者静息态脑功能连接改变,为探索偏头痛的发病机制提供影像学资料。方法收集16例偏头痛患者与16例健康对照,采集rfMRI成像,计算低频振幅,找出感兴趣区做功能连接进行统计分析。结果偏头痛患者左侧岛叶、左侧额下回低频振幅显著低于对照组,右侧视觉皮质低频振幅显著高于对照组;以左侧额下回、右侧枕中回为感兴趣区,发现左侧额下回与脑干之间的功能连接增强,与双侧枕叶之间的功能连接减弱;右侧枕中回与双侧楔前叶延伸至扣带回中部区域之间的功能连接增强,与双侧中央前回、双侧缘上回、双侧颞上回及双侧额下回之间的功能连接减弱。结论偏头痛患者无头痛发作时神经元活动强度改变,大脑功能连接异常,这导致大脑整合信息过程改变,并与偏头痛发病相关。     

A functional magnetic resonance imaging study during sentence reading in Japanese dyslexic children

A functional magnetic resonance imaging (fMRI) study during Japanese 'kana' readings was performed on Japanese dyslexic children. Five dyslexic children (aged 9-12 years) and five healthy children (aged 9-11 years) were investigated. The fMRI examination was performed by getting these children to read sentences constructed from Japanese phonograms, 'kana', compared with staring at meaningless figures as a control task. All control subjects showed activation of the left middle temporal gyrus. In the dyslexic children, the activation of the middle temporal gyrus was rather vague. However, other distinctively activated regions were detected as follows: the bilateral occipital cortex in two dyslexics, the inferior part of the frontal regions in two other dyslexics, and both the bilateral occipital cortex and the inferior part of precentral gyrus in the remaining one. These results indicate compensatory management processes for the unskilled reading ability of dyslexic children. The present results were similar to previous ones for adult dyslexia with the Roman alphabet, and suggest that brain malfunction in dyslexia during the task of reading must be common despite differences in languages.     

~(18)F-FDG PET显像观察特发性快眼动睡眠期行为障碍患者脑葡萄糖代谢特点的研究

目的探讨~(18)F-FDG PET显像观察特发性快眼动睡眠期行为障碍(iRBD)患者脑葡萄糖代谢改变和iRBD脑葡萄糖代谢改变与病程间的相关性。方法纳入多导睡眠监测(PSG)确诊的iRBD患者20例(iRBD组)和年龄、性别匹配的健康对照者19例(对照组)。两组均行~(18)F-FDG PET脑显像。基于自动解剖标记模板将大脑划分为90个左右对称的脑区,计算各脑区葡萄糖代谢半定量值。对iRBD组和对照组各脑区葡萄糖代谢半定量值进行独立样本t检验;并对iRBD组脑葡萄糖代谢改变与病程行Pearson相关分析。结果 (1)与对照组比较,iRBD组的双侧背外侧额上回、双侧眶部额上回、双侧眶部额中回、双侧海马、双侧海马旁回、双侧杏仁核、左侧眶部额下回、左侧岛叶、左侧内侧与旁扣带脑回、左侧中央旁小叶、左侧苍白球的葡萄糖代谢半定量值均增高(P0.05);双侧距状裂周围皮质、双侧楔叶、双侧舌回、双侧枕上回、双侧枕中回、双侧枕下回、双侧角回、双侧颞上回、双侧颞中回、右侧颞横回的葡萄糖代谢半定量值均降低(P0.05)。Pearson相关分析结果,iRBD组双侧杏仁核、双侧颞上回、右侧楔叶、右侧枕上回、右侧颞横回、左侧海马、左侧颞中回的葡萄糖代谢半定量值与病程呈正相关(P0.05);而双侧眶部额上回、双侧眶部额中回、左侧中央旁小叶、左侧眶部额下回、左侧内侧和旁扣带回、右侧背外侧额上回、右侧海马旁回的葡萄糖代谢半定量值与病程呈负相关(P0.05)。结论 iRBD患者脑内存在疾病相关的葡萄糖代谢水平改变,有助于客观评估iRBD病情的变化。     

A procedure for identifying regions preferentially activated by attention to semantic and phonological relations using functional magnetic resonance imaging

A procedure is introduced for using functional magnetic resonance imaging (fMRI) techniques to identify neural regions associated with attention to semantic and phonological aspects of written words within a single group of subjects. Short lists (16 words/list), consisting of visually-presented semantically-related words (bed, rest) or rhyming words (weep, beep) were presented rapidly to subjects, who were asked to attend to the relations among the words. Regions preferentially involved in attention to semantic relations appeared within left anterior/ventral inferior frontal gyrus (IFG, approximate Brodmann Area, BA47), left posterior/dorsal IFG (BA44/45), left superior/middle temporal cortex (BA22/21), left fusiform gyrus (BA37), and right cerebellum. Regions preferentially involved in attention to phonological relations appeared within left inferior frontal cortex (near BA6/44, posterior to the semantic regions within IFG described above) and within bilateral inferior parietal cortex (BA40) and precuneus (BA7). This method is notable in that a comparison of the two tasks within some of the individual subjects revealed activation patterns similar to the group average, especially within left inferior frontal and left superior/middle parietal cortices. This fact combined with the efficiency with which the data can be obtained (here, in about an hour of functional scanning) and the adaptability of the task for many different subject populations suggests a wide range of possibilities for this technique: it could be used to track language development (e.g. in children), compare language organization across subject populations (e.g. for dyslexic or blind subjects), and identify language regions within individuals (e.g. potentially to aid in surgical planning).     

Developmental and skill effects on the neural correlates of semantic processing to visually presented words

Functional magnetic resonance imaging (fMRI) was used to explore the neural correlates of semantic judgments to visual words in a group of 9- to 15-year-old children. Subjects were asked to indicate if word pairs were related in meaning. Consistent with previous findings in adults, children showed activation in bilateral inferior frontal gyri (Brodmann area [BA] 47, 45) and left middle temporal gyrus (BA 21). Words with strong semantic association elicited significantly greater activation in bilateral inferior parietal lobules (BA 40), suggesting stronger integration of highly related semantic features. By contrast, words with weak semantic association elicited greater activation in left inferior frontal gyrus (BA 45) and middle temporal gyrus (BA 21), suggesting more difficult feature search and more extensive access to semantic representations. We also examined whether age and skill explained unique variance in the patterns of activation. Increasing age was correlated with greater activation in left middle temporal gyrus (BA 21) and inferior parietal lobule (BA 40), suggesting that older children have more elaborated semantic representations and more complete semantic integration processes, respectively. Decreasing age was correlated with activation in right superior temporal gyrus (BA 22) and decreasing accuracy was correlated with activation in right middle temporal gyrus (BA 21), suggesting the engagement of ancillary systems in the right hemisphere for younger and lower-skill children.     

Graph theory analysis of resting‐state functional magnetic resonance imaging in essential tremor

Essential tremor (ET) is a neurological disease with both motor and nonmotor manifestations; however, little is known about its underlying brain basis. Furthermore, the overall organization of the brain network in ET remains largely unexplored. We investigated the topological properties of brain functional network, derived from resting‐state functional magnetic resonance imaging (MRI) data, in 23 ET patients versus 23 healthy controls. Graph theory analysis was used to assess the functional network organization. At the global level, the functional network of ET patients was characterized by lower small‐worldness values than healthy controls—less clustered functionality of the brain. At the regional level, compared with the healthy controls, ET patients showed significantly higher values of global efficiency, cost and degree, and a shorter average path length in the left inferior frontal gyrus (pars opercularis), right inferior temporal gyrus (posterior division and temporo‐occipital part), right inferior lateral occipital cortex, left paracingulate, bilateral precuneus bilaterally, left lingual gyrus, right hippocampus, left amygdala, nucleus accumbens bilaterally, and left middle temporal gyrus (posterior part). In addition, ET patients showed significant higher local efficiency and clustering coefficient values in frontal medial cortex bilaterally, subcallosal cortex, posterior cingulate cortex, parahippocampal gyri bilaterally (posterior division), right lingual gyrus, right cerebellar flocculus, right postcentral gyrus, right inferior semilunar lobule of cerebellum and culmen of vermis. Finally, the right intracalcarine cortex and the left orbitofrontal cortex showed a shorter average path length in ET patients, while the left frontal operculum and the right planum polare showed a higher betweenness centrality in ET patients. In conclusion, the efficiency of the overall brain functional network in ET is disrupted. Further, our results support the concept that ET is a disorder that disrupts widespread brain regions, including those outside of the brain regions responsible for tremor.     

注意缺陷多动障碍儿童静息态的脑功能磁共振成像研究

目的 探讨注意缺陷多动障碍(ADHD)儿童静息态脑功能磁共振成像的特点.方法 对15名正常学龄期儿童(对照组)和14例ADHD儿童(ADHD组)进行静息态功能磁共振成像(fMRI)扫描,采用局部一致性(ReHo)作为测最指标.结果 ADHD组在双侧顶下小叶(Z=3.73,Z=3.34)、双侧楔叶(Z=3.42,Z=3.86)、左侧额中回(Z=3.24)、左侧颢中同(Z=3.24)、左侧楔前叶(Z=3.45)及右侧岛叶(Z=3.09)、右侧小脑(Z=3.42)等区域的ReHo值低于对照组,而双侧额下回(Z=3.19,Z=2.93)的ReHo值高于对照组.结论与对照组比较,静息态下ADHD患者与执行控制功能、注意认知功能及默认网络功能等相关区域存在异常.     

Specialization of phonological and semantic processing in Chinese word reading

The purpose of this study was to examine the neurocognitive network for processing visual word forms in native Chinese speakers using functional magnetic resonance imaging (fMRI). In order to compare the processing of phonological and semantic representations, we developed parallel rhyming and meaning association judgment tasks that required explicit access and manipulation of these representations. Subjects showed activation in left inferior/middle frontal gyri, bilateral medial frontal gyri, bilateral middle occipital/fusiform gyri, and bilateral cerebella for both the rhyming and meaning tasks. A direct comparison of the tasks revealed that the rhyming task showed more activation in the posterior dorsal region of the inferior/middle frontal gyrus (BA 9/44) and in the inferior parietal lobule (BA 40). The meaning task showed more activation in the anterior ventral region of the inferior/middle frontal gyrus (BA 47) and in the superior/middle temporal gyrus (BA 22,21). These findings are consistent with previous studies in English that suggest specialization of inferior frontal regions for the access and manipulation of phonological vs. semantic representations, but also suggest that this specialization extends to the middle frontal gyrus for Chinese. These findings are also consistent with the suggestion that the left middle temporal gyrus is involved in representing semantic information and the left inferior parietal lobule is involved in mapping between orthographic and phonological representations.     

Word and picture matching: a PET study of semantic category effects

We report two positron emission tomography (PET) studies of cerebral activation during picture and word matching tasks, in which we compared directly the processing of stimuli belonging to different semantic categories (animate and inanimate) in the visual (pictures) and verbal (words) modality. In the first experiment, brain activation was measured in eleven healthy adults during a same/different matching task for textures, meaningless shapes and pictures of animals and artefacts (tools). Activations for meaningless shapes when compared to visual texture discrimination were localized in the left occipital and inferior temporal cortex. Animal picture identification, either in the comparison with meaningless shapes and in the direct comparison with non-living pictures, involved primarily activation of occipital regions, namely the lingual gyrus bilaterally and the left fusiform gyrus. For artefact picture identification, in the same comparison with meaningless shape-baseline and in the direct comparison with living pictures, all activations were left hemispheric, through the dorsolateral frontal (Ba 44/6 and 45) and temporal (Ba 21, 20) cortex. In the second experiment, brain activation was measured in eight healthy adults during a same/different matching task for visually presented words referring to animals and manipulable objects (tools); the baseline was a pseudoword discrimination task. When compared with the tool condition, the animal condition activated posterior left hemispheric areas, namely the fusiform (Ba 37) and the inferior occipital gyrus (Ba 18). The right superior parietal lobule (Ba 7) and the left thalamus were also activated. The reverse comparison (tools vs animals) showed left hemispheric activations in the middle temporal gyrus (Ba 21) and precuneus (Ba 7), as well as bilateral activation in the occipital regions. These results are compatible with different brain networks subserving the identification of living and non-living entities; in particular, they indicate a crucial role of the left fusiform gyrus in the processing of animate entities and of the left middle temporal gyrus for tools, both from words and pictures. The activation of other areas, such as the dorsolateral frontal cortex, appears to be specific for the semantic access of tools only from pictures.     

The hippocampal system mediates logical reasoning about familiar spatial environments

It has recently been shown that syllogistic reasoning engages two dissociable neural systems. Reasoning about familiar situations engages a frontal-temporal lobe system, whereas formally identical reasoning tasks involving unfamiliar situations recruit a frontal-parietal visuospatial network. These two systems may correspond to the "heuristic" and "formal" methods, respectively, postulated by cognitive theory. To determine if this dissociation generalizes to reasoning about transitive spatial relations, we studied 14 volunteers using event-related fMRI, as they reasoned about landmarks in familiar and unfamiliar environments. Our main finding is a task (reasoning and baseline) by spatial content (familiar and unfamiliar) interaction. Modulation of reasoning toward unfamiliar landmarks resulted in bilateral activation of superior and inferior parietal lobules (BA 7, 40), dorsal superior frontal cortex (BA 6), and right superior and middle frontal gyri (BA 8), regions widely implicated in visuospatial processing. By contrast, modulation of the reasoning task toward familiar landmarks, engaged the right inferior/orbital frontal gyrus (BA 11/47), bilateral occipital (BA 18, 19), and temporal lobes. The temporal lobe activation included the right inferior temporal gyrus (BA 37), posterior hippocampus, and parahippocampal gyrus, regions implicated in spatial memory and navigation tasks. These results provide support for the generalization of dual mechanism theory to transitive reasoning and highlight the importance of the hippocampal system in reasoning about familiar spatial environments.     

Learning face-name associations and the effect of age and performance: a PET activation study

Learning face-name associations is a complex task to be mastered in every day life that approaches the limits of cognitive capacity in most normal humans. We studied brain activation during face-name learning using positron emission tomography (PET) in 11 normal volunteers. The most intense activation was seen in occipital association cortex (BA 18) bilaterally, also involving lingual and fusiform gyrus (BA 37). In the left hemisphere additional activation were located in inferior temporal gyrus, the inferior part of pre- and postcentral gyrus, and orbitofrontal cortex (BA 11), whereas in the right hemisphere only a region in the precuneus (BA 19) was activated additionally. There was considerable interindividual variation of encoding success, which was significantly related to activation of BA 18 bilaterally. Subject ages covered a range of 26-72 years, but - in contrast to the effect of encoding success - there was no significant age effect on activations. Task-independent habituation effects were seen in cerebellum and left middle temporal gyrus. These results indicate that the intensity of information processing in ventral occipital association cortex is most important for success of face-name encoding. Learning is further mediated by a predominantly left-hemispheric network including inferior temporal and orbitofrontal cortex.     

Interconnected large-scale systems for three fundamental cognitive tasks revealed by functional MRI

The specific brain areas required to execute each of three fundamental cognitive tasks - object naming, same-different discrimination, and integer computation - are determined by whole-brain functional magnetic resonance imaging (fMRI) using a novel technique optimized for the isolation of neurocognitive systems. This technique (1) conjoins the activity associated with identical or nearly identical tasks performed in multiple sensory modalities (conjunction) and (2) isolates the activity conserved across multiple subjects (conservation). Cortical regions isolated by this technique are, thus, presumed associated with cognitive functions that are both distinguished from primary sensory processes and from individual differences. The object-naming system consisted of four brain areas: left inferior frontal gyrus, Brodmann's areas (BAs) 45 and 44; left superior temporal gyrus, BA 22; and left medial frontal gyrus, BA 6. The same-different discrimination system consisted of three brain areas: right inferior parietal lobule, BA 40; right precentral gyrus, BA 6; and left medial frontal gyrus, BA 6. The integer computation system consisted of five brain areas: right middle frontal gyrus, BA 6; right precentral gyrus, BA 6; left inferior parietal lobule, BA 40; left inferior frontal gyrus, BA 44; and left medial frontal gyrus, BA 6. All three neurocognitive systems shared one common cortical region, the left medial frontal gyrus, the object-naming and integer computation systems shared the left inferior frontal gyrus, and the integer computation and same-different discrimination systems shared the right precentral gyrus. These results are consistent with connectionist models of cognitive processes where specific sets of remote brain areas are assumed to be transiently bound together as functional units to enable these functions, and further suggest a superorganization of neurocognitive systems where single brain areas serve as elements of multiple functional systems.     

An fMRI study comparing brain activation between word generation and electrical stimulation of language-implicated acupoints

We compared the brain activation on functional magnetic resonance imaging (MRI) during word generation with the activation during electrical stimulation of two language-implicated acupoints in 17 healthy, Mandarin-speaking, Chinese male volunteers (age 19-26 years). All subjects were strongly right handed according to a handedness inventory. Using a standard functional MRI procedure and a word-generation paradigm, significant activation was seen in the left and right inferior frontal gyri (BA 44, 45) as well as the left superior temporal gyrus (BA 22, 42). Stronger activation with a larger volume was seen in the left hemisphere. Electrical stimulation of either one of the two language-implicated acupoints, SJ 8 (11 subjects) and Du 15 (6 subjects), without the word-generation paradigm in the same cohort, produced significant activation in the right inferior frontal gyrus (BA 44, 46) and in the left and right superior temporal gyri (BA 22, 42), respectively. Nevertheless, no activation was seen in the left inferior frontal gyrus. In addition, electrical stimulation of the adjacent non-acupoints did not produce any significant brain activation. Although our results support the notion of acupoint-brain activation, applying acupuncture at SJ 8 or Du 15 does not activate the typical language areas in the left inferior frontal cortex.