Motor and extra-motor gray matter integrity may underlie neurophysiologic parameters of motor function in amyotrophic lateral sclerosis: a combined voxel-based morphometry and transcranial stimulation study

The association between gray matter (GM) density and neurophysiologic changes is still unclear in amyotrophic lateral sclerosis (ALS). We evaluated the relationship between GM density and motor system integrity combining voxel-based morphometry (VBM) and transcranial magnetic stimulation (TMS) in ALS. We included 17 ALS patients and 22 healthy controls (HC) who underwent 3D-T1-weighted imaging. Among the ALS group, we applied left motor cortex single-pulse TMS. We used whole-brain VBM comparing ALS and HC in GM density. We also conducted regression analysis to examine correlations between GM density and the following TMS parameters: motor evoked potential (MEP)/M ratio and central motor conduction time (CMCT). We found significantly decreased GM density in ALS patients in several frontal, temporal, parietal/occipital and cerebellar regions (p?<?0.001 uncorrected; cluster-extent threshold k?=?100 voxels per cluster). With regards to TMS parameters, ALS patients showed mostly increased MEP/M ratio and modest prolongation of CMCT. MEP/M ratio was associated with GM density in (a) rolandic operculum/inferior frontal gyrus/precentral gyrus; anterior cingulate gyrus; inferior temporal gyrus; superior parietal lobule; cuneus; superior occipital gyrus and cerebellum (positive association) and (b) paracentral lobule/supplementary motor area (negative association). CMCT was associated with GM density in (a) inferior frontal gyrus and middle cingulated gyrus (positive association) and (b) superior parietal lobule; cuneus and cerebellum (negative association). Our findings support a significant interaction between motor and extra-motor structural and functional changes and highlight that motor and extra-motor GM integrity may underlie TMS parameters of motor function in ALS patients.     

Proton magnetic resonance spectroscopy of the inferior frontal gyrus and thalamus and its relationship to verbal learning task performance in patients with schizophrenia: a preliminary report

Previous research has found frontal lobe involvement in memory impairment in schizophrenia. In the present study, proton magnetic resonance spectroscopy was performed in 13 young patients with schizophrenia and 13 normal control subjects. Spectra were obtained from a voxel of 2 x 2 x 1.5 cm(3) in the bilateral inferior frontal gyrus and thalamus. Subjects were given a verbal learning task and stimulus category repetition (SCR) was calculated from the performance of the task. Significantly reduced N-acetylaspartate (NAA)/choline-containing compounds ratios were found in the left inferior frontal cortex of patients compared with controls. The total number of words recalled by patients was significantly lower than that recalled by controls. In all subjects, SCR scores were positively correlated with NAA/phosphocreatine ratios of the left inferior frontal cortex, which showed a trend towards a decrease in patients. These results support the notion of metabolic abnormalities in the left inferior frontal region related to verbal memory deficits in patients with schizophrenia.     

太溪和丘墟穴捻针时不同脑功能区的激活

A number of previous studies of acupuncture acupoint specificity have used sham acupoints,sham acupuncture or meridian acupoints at a great distance from each other as controls in functional MRI (fMRI) experiments.However,few studies have compared different meridian acupoints within the same segment,which are associated with similarly intense needle sensations.We performed fMRI on 12 healthy young volunteers and observed differences in brain activation elicited by acupuncture of the Taixi (KI 3) and Qiuxu (GB 40) acupoints.Acupuncture was applied at the Taixi and Qiuxu acupoints,using a multiple-block fMRI design with three blocks,involving three alternations of resting and task phases.After scanning,needle sensation was assessed.The behavioral results revealed that the subjective needle sensation was similar between the Taixi and Qiuxu acupoints.The fMRI results revealed that acupuncture at the right Taixi acupoint activated the right superior temporal gyrus (BA 22),left middle frontal gyrus (BA 46) and inferior frontal gyrus (BA 45),bilateral parietal lobe postcentral gyrus (BA 2),right parietal lobe (BA 3),and left parietal lobe (BA 40).Acupuncture at the right Qiuxu acupoint activated the left superior temporal gyrus (BA 42),right parietal lobe postcentral gyrus (BA 40,BA 43),right inferior frontal gyrus (BA 47),bilateral superior temporal gyrus (BA 22),and right insula BA13.These results suggest that the right Taixi and Qiuxu acupoints activated different brain areas.     

基于颅骨骨窗的国人大脑功能区定位

目的 探讨基于颅骨骨窗划分的国人大脑重要功能区定位关系。方法 选取13具成人尸头,保留颞上线、鳞状线、矢状缝、冠状缝、人字缝、前囟点、冠状点、鼻根等骨性标志,形成额骨上窗、额骨下窗、顶骨上窗、顶骨下窗、颞骨窗、枕骨窗共六个骨窗,观测中央前回、中央后回、额下回等重要脑功能区以及脑膜中动脉在各骨窗内的定位和分布情况。结果 中央前回分布于额骨上窗、顶骨上窗,其中点在中线上位于前囟点后方约4.2 cm[右侧（4.17±0.92）cm,左侧（4.31±1.1）cm],与矢状缝夹角约54°[右侧（53.6±7.47）°,左侧（54.63±3.54）°]。中央后回位于顶骨下窗,其中点在中线上位于前囟点后方约6.2 cm[右侧（64.51±0.87）°,左侧（63.63±1.76）°],与矢状缝夹角约64°[右侧（64.51±0.87）°,左侧（63.63±1.76）°]。额下回位于额骨下窗,而颞上回及颞横回的大部分位于颞骨窗,距状沟则位于枕骨窗;脑膜中动脉仅分布在顶骨上、下窗,其出现率分别为73.12%、67.42%。结论 基于颅骨骨窗划分的大脑重要功能区的定位关系对于术前规划及术中定位有一定指导意义。     

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.     

Cerebral glucose metabolism in five patients with Lennox-Gastaut syndrome

Regional cerebral glucose metabolic rates were estimated by positron emission tomography, in parallel with electroencephalography and cranial computed tomography in 5 patients with Lennox-Gastaut syndrome. The 5 patients, 3 boys and 2 girls, ranged in age from 10-15 years. Computed tomography revealed no gross abnormalities. Each patient received 2-5 mCi of 2-(18F)-fluoro-2-deoxy-D-glucose (18F-FDG) intravenously. Averaged cerebral glucose metabolic rates were reduced in each cerebral region as compared with controls. Unilateral hypometabolism was present in 4 patients: one in the inferior frontal gyrus as well as the posterior portion of the superior temporal gyrus; one in the inferior frontal gyrus; one in the posterior portion of the superior temporal gyrus; and one demonstrated diffuse hemispheric hypometabolism including the inferior frontal and posterior portion of the superior temporal gyrus. The side of hypometabolism was the same as the epileptogenic focus on the electroencephalogram. No focal changes were demonstrated on the electroencephalogram of a patient whose positron emission tomography revealed hemispheric hypometabolism. Hypometabolism of the inferior frontal and posterior portion of the superior temporal gyrus may relate to the possible pathogenesis of Lennox-Gastaut syndrome. Positron emission tomography has the potential to reveal a latent focal or lateralized abnormality in some patients with non-localized electroencephalographic changes.     

捻转和非捻转刺激太溪穴后脑激活状态的功能磁共振成像研究

目的：观察功能磁共振成像了解捻转刺激太溪穴和非捻转刺激所引起的脑激活区状态。 方法：纳入健康青年志愿者12名,选取右侧太溪穴,采用组块刺激模式,静息阶段与刺激阶段交替出现,重复3次,分为3个组块。刺激为手法捻转行针或非捻转,非捻转即手放在针柄,但不进行任何操作。扫描后图像使用SPM2进行后处理。 结果：捻转刺激太溪穴主要激活了右侧颞上回BA22,左侧的额中回BA46,其次为左右顶叶的中央后回BA2,BA3,左额叶的额下回BA45和左顶叶的顶下小叶BA40;而非捻转刺激则没有激活。 结论：捻转刺激太溪穴和非捻转刺激的激活不同,与本经相关的经络、脏腑联系密切相关。     

Self-face recognition in children with autism spectrum disorders: a near-infrared spectroscopy study

It is assumed that children with autism spectrum disorders (ASD) have specificities for self-face recognition, which is known to be a basic cognitive ability for social development. In the present study, we investigated neurological substrates and potentially influential factors for self-face recognition of ASD patients using near-infrared spectroscopy (NIRS). The subjects were 11 healthy adult men, 13 normally developing boys, and 10 boys with ASD. Their hemodynamic activities in the frontal area and their scanning strategies (eye-movement) were examined during self-face recognition. Other factors such as ASD severities and self-consciousness were also evaluated by parents and patients, respectively. Oxygenated hemoglobin levels were higher in the regions corresponding to the right inferior frontal gyrus than in those corresponding to the left inferior frontal gyrus. In two groups of children these activities reflected ASD severities, such that the more serious ASD characteristics corresponded with lower activity levels. Moreover, higher levels of public self-consciousness intensified the activities, which were not influenced by the scanning strategies. These findings suggest that dysfunction in the right inferior frontal gyrus areas responsible for self-face recognition is one of the crucial neural substrates underlying ASD characteristics, which could potentially be used to evaluate psychological aspects such as public self-consciousness.     

Neuroanatomical correlates of phonological processing of Chinese characters and alphabetic words: a meta-analysis

We used the activation likelihood estimation (ALE) method to quantitatively synthesize data from 19 published brain mapping studies of phonological processing in reading, six with Chinese and 13 with alphabetic languages. It demonstrated high concordance of cortical activity across multiple studies in each written language system as well as significant differences of activation likelihood between languages. Four neural systems for the phonological processing of Chinese characters included: (1) a left dorsal lateral frontal system at Brodmann area (BA) 9; (2) the dorsal aspect of left inferior parietal system; (3) a bilateral ventral-occipitotemporal system including portions of fusiform gyrus and middle occipital gyrus; and (4) a left ventral prefrontal system covering the superior aspect of inferior frontal gyrus. For phonological processing of written alphabetic words, cortical areas identified here are consistent with the three neural systems proposed previously in the literature: (1) a ventral prefrontal system involving superior portions of left inferior frontal gyrus; (2) a left dorsal temporoparietal system including mid-superior temporal gyri and the ventral aspect of inferior parietal cortex (supramarginal region); and (3) a left ventral occipitotemporal system. Contributions of each of these systems to phonological processing in reading were discussed, and a covariant learning hypothesis is offered to account for the findings that left middle frontal gyrus is responsible for addressed phonology in Chinese whereas left temporoparietal regions mediate assembled phonology in alphabetic languages. Language form, cognitive process, and learning strategy drive the development of functional neuroanatomy.     

Increase in prefrontal cortex serotonin 2A receptors following estrogen treatment in postmenopausal women

OBJECTIVE: This study investigated the effect of estrogen on brain serotonin 2A (5-HT(2A)) receptors in postmenopausal women and whether there was any correlation of receptor changes with cognition and mood. METHOD: Ten postmenopausal subjects underwent positron emission tomography measurements of 5-HT(2A) receptor binding with [(18)F]deuteroaltanserin before and after estrogen replacement therapy. RESULTS: 5-HT(2A) receptor binding was significantly increased after estrogen replacement therapy in the right prefrontal cortex (right precentral gyrus [Brodmann's area 9], inferior frontal gyrus [Brodmann's area 47], medial frontal gyrus [Brodmann's area 6, 10] and the anterior cingulate cortex [Brodmann's area 32]). In the inferior frontal gyrus [Brodmann's area 44]), receptor up-regulation was correlated with change in plasma estradiol. Verbal fluency and Trail Making Test performance, but not mood, were significantly improved by estrogen without correlation with receptor changes. CONCLUSIONS: Estrogen increases 5-HT(2A) receptor binding in human prefrontal regions.     

Speech planning and execution in children who stutter: Preliminary findings from a fNIRS investigation

Few studies have investigated the neural mechanisms underlying speech production in children who stutter (CWS), despite the critical importance of understanding these mechanisms closer to the time of stuttering onset. The relative contributions of speech planning and execution in CWS therefore are also unknown. Using functional near-infrared spectroscopy, the current study investigated neural mechanisms of planning and execution in a small sample of 9–12 year-old CWS and controls (N = 12) by implementing two tasks that manipulated speech planning and execution loads. Planning was associated with atypical activation in bilateral inferior frontal gyrus and right supramarginal gyrus. Execution was associated with atypical activation in bilateral precentral gyrus and inferior frontal gyrus, as well as right supramarginal gyrus and superior temporal gyrus. The CWS exhibited some activation patterns that were similar to the adults who stutter (AWS) as reported in our previous study: atypical planning in frontal areas including left inferior frontal gyrus and atypical execution in fronto-temporo-parietal regions including left precentral gyrus, and right inferior frontal, superior temporal, and supramarginal gyri. However, differences also emerged. Whereas CWS and AWS both appear to exhibit atypical activation in right inferior and supramarginal gyri during execution, only CWS appear to exhibit this same pattern during planning. In addition, the CWS appear to exhibit atypical activation in left inferior frontal and right precentral gyri related to execution, whereas AWS do not. These preliminary results are discussed in the context of possible impairments in sensorimotor integration and inhibitory control for CWS.     

Frontal cortex functional connectivity changes during sound categorization

Using functional connectivity analysis of functional magnetic resonance imaging data, we investigated the role of the inferior frontal gyrus in categorization of simple sounds. We found stronger functional connectivity between left inferior frontal gyrus and auditory processing areas in the temporal cortex during categorization of speech (vowels, syllables) and nonspeech (tones, combinations of tones and sweeps) sounds relative to an auditory discrimination task; the hemispheric lateralization varied depending on the speech-like properties of the sounds. Our results attest to the importance of interactions between temporal cortex and left inferior frontal gyrus in sound categorization. Further, we found different functional connectivity patterns between left inferior frontal gyrus and other brain regions implicated in categorization of syllables compared with other stimuli, reflecting the greater facility for categorization of syllables.     

首发精神分裂症患者的功能磁共振初步研究

目的 利用血氧水平依赖性(blood oxygenation level-dependent,BOLD)功能磁共振成像(functional magnetic resonance imaging,fMRI)技术探讨首发精神分裂症患者治疗前后认知功能激发图像的特点。方法 13例首发精神分裂症患者入组,用利培酮或氯丙嗪治疗后9例患者复查fMRI。以词语流畅性作业(verbal fluency task,VF)作为任务,采用Block设计,用梯度回波-平面回波成像(GRE-EPI)序列采集数据,经工作站处理后获功能图像。结果 (1)VF激活受试者的额叶(前额叶)、顶叶及颞叶皮层;(2)复查的9例受试者中,7例激活增强,2例激活减弱;(3)治疗后激活增强的7例受试者的双侧额上、中、下回激活有增加趋势,而双侧颞上、中、下回激活有减少趋势(P>0.05);但左额叶背外侧面治疗后的激活明显强于治疗前(P=0.032)。结论 BOLD-fMRI可用于研究人脑的高级认知功能。首发精神分裂症患者治疗前后脑功能图像有明显变化,提示认知缺陷症状是可以治疗的。     

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.     

Differential roles of inferior frontal and inferior parietal cortex in task switching: Evidence from stimulus‐categorization switching and response‐modality switching

We used fMRI to investigate both common and differential neural mechanisms underlying two distinct types of switching requirements, namely switching between stimulus categorizations (color vs. form) and switching between response modalities (hand vs. foot responses). Both types of switching induced similar behavioral shift costs. However, at the neural level, switching between stimulus categorizations led to left‐hemispheric activations including the inferior frontal gyrus as well as the intraparietal sulcus extending to the superior parietal gyrus and the supramarginal gyrus. In contrast, switching between response modalities was associated mainly with left‐hemispheric activation of the intraparietal sulcus and the supramarginal gyrus. A conjunction analysis indicated common activation of the left intraparietal sulcus and the supramarginal gyrus for both types of switching. Together, these results qualify previous claims about a general role of the left prefrontal cortex in task control by suggesting that the left inferior frontal gyrus is specifically involved in switching between stimulus categorizations, whereas parietal cortex is more generally implicated in the selection of action rules. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.     

Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study

Aphasia is an acquired language disorder that is a common consequence of stroke.The pathogenesis of the disease is not fully understood,and as a result,current treatment options are not satisfactory.Here,we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke.Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language.The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults.The activation frequency,volumes,and intensity in the regions related to language,such as the left inferior frontal gyrus(Broca's area),the left superior temporal gyrus,and the right inferior frontal gyrus(the mirror region of Broca's area),were lower in patients compared with healthy adults.In contrast,activation in the right superior temporal gyrus,the bilateral superior parietal lobule,and the left inferior temporal gyrus was stronger in patients compared with healthy controls.These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas.     

Evidence of cortical reorganization of language networks atfer stroke with subacute Broca’s aphasia:a blood oxygenation level dependent-functional magnetic resonance imaging study

Aphasia is an acquired language disorder that is a common consequence of stroke. hTe pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic reso-nance imaging to evaluate the activation of bilateral cortices in patients with Broca’s aphasia 1 to 3 months atfer stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of lan-guage. hTe activation areas in the letf hemisphere of aphasia patients were signiifcantly smaller compared with those in healthy adults. hTe activation frequency, volumes, and intensity in the regions related to language, such as the letf inferior frontal gyrus (Broca’s area), the letf superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca’s area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the letf inferior temporal gyrus was stronger in patients compared with healthy controls. hTese results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas.     

The relationship between prefrontal brain volume and characteristics of memory strategy in schizophrenia spectrum disorders

The present study investigated the relationship between memory strategy use and prefrontal gray/white matter volumes of healthy control subjects, patients with schizophrenia or schizotypal disorder. Gray/white matter volumes were measured for the superior, middle, inferior, ventral medial and orbital prefrontal regions, using high-resolution magnetic resonance (MR) images that were acquired from 35 patients with schizophrenia, 25 patients with schizotypal disorder and 19 healthy subjects. Participants were also administered the Japanese Verbal Learning Test (JVLT). In control subjects, larger left inferior frontal and straight gyrus's gray matter volumes were associated with higher semantic clustering rates on the JVLT, and smaller left inferior frontal gray matter volumes were associated with higher serial clustering ratio. In schizophrenic patients, smaller left orbitofrontal gray matter volumes were associated with lower semantic clustering rates on the JVLT. In schizotypal patients, smaller left inferior frontal white matter volume was associated with smaller serial clustering rates and larger semantic clustering rate. These findings suggest that semantic organization in schizophrenic patients might depend on mobilization of a memory strategy that is mediated by orbitofrontal cortex functioning. Failure to use a semantic organization strategy might be related to reduced volume in the inferior frontal gyrus. The findings for schizotypal patients suggest a compensation mechanism to remember the words using a serial processing strategy is at work when the inferior frontal gyrus cannot mediate semantic processing.     

Inferences during story comprehension: cortical recruitment affected by predictability of events and working memory capacity

Although it has been consistently shown that readers generate bridging inferences during story comprehension, little is currently known about the neural substrates involved when people generate inferences and how these substrates shift with factors that facilitate or impede inferences, such as whether inferences are highly predictable or unpredictable. In the current study, functional magnetic resonance imaging (fMRI) signal increased for highly predictable inferences (relative to events that were previously explicitly stated) bilaterally in both the superior temporal gyri and the inferior frontal gyri. Interestingly, high working memory capacity comprehenders, who are most likely to generate inferences during story comprehension, showed greater signal increases than did low working memory capacity comprehenders in the right superior temporal gyrus and right inferior frontal gyrus. When comprehenders needed to draw unpredictable inferences in a story, fMRI signal increased relative to explicitly stated events in the left inferior gyrus and in the middle frontal gyrus, irrespective of working memory capacity. These results suggest that the predictability of a text (i.e., the causal constraint) and the working memory capacity of the comprehender influence the different neural substrates involved during the generation of bridging inferences.     

Different patterns and development characteristics of processing written logographic characters and alphabetic words: An ALE meta‐analysis

The neural systems for phonological processing of written language have been well identified now, while models based on these neural systems are different for different language systems or age groups. Although each of such models is mostly concordant across different experiments, the results are sensitive to the experiment design and intersubject variability. Activation likelihood estimation (ALE) meta‐analysis can quantitatively synthesize the data from multiple studies and minimize the interstudy or intersubject differences. In this study, we performed two ALE meta‐analysis experiments: one was to examine the neural activation patterns of the phonological processing of two different types of written languages and the other was to examine the development characteristics of such neural activation patterns based on both alphabetic language and logographic language data. The results of our first meta‐analysis experiment were consistent with the meta‐analysis which was based on the studies published before 2005. And there were new findings in our second meta‐analysis experiment, where both adults and children groups showed great activation in the left frontal lobe, the left superior/middle temporal gyrus, and the bilateral middle/superior occipital gyrus. However, the activation of the left middle/inferior frontal gyrus was found increase with the development, and the activation was found decrease in the following areas: the right claustrum and inferior frontal gyrus, the left inferior/medial frontal gyrus, the left middle/superior temporal gyrus, the right cerebellum, and the bilateral fusiform gyrus. It seems that adults involve more phonological areas, whereas children involve more orthographic areas and semantic areas. Hum Brain Mapp 35:2607–2618, 2014. © 2013 Wiley Periodicals, Inc .