Differential activation of frontal and parietal regions during visual word recognition: an optical topography study

The present study examined cortical oxygenation changes during lexical decision on words and pseudowords using functional Near-Infrared Spectroscopy (fNIRS). Focal hyperoxygenation as an indicator of functional activation was compared over three target areas over the left hemisphere. A 52-channel Hitachi ETG-4000 was used covering the superior frontal gyrus (SFG), the left inferior parietal gyrus (IPG) and the left inferior frontal gyrus (IFG). To allow for anatomical inference a recently developed probabilistic mapping method was used to determine the most likely anatomic locations of the changes in cortical activation [Tsuzuki, D., Jurcak, V., Singh, A.K., Okamoto, M., Watanabe, E., Dan, I., 2007. Virtual spatial registration of stand-alone fNIRS data to MNI space. NeuroImage 43 (4), 1506-1518. Subjects made lexical decisions on 50 low and 50 high frequency words and 100 pseudowords. With respect to the lexicality effect, words elicited a larger focal hyperoxygenation in comparison to pseudowords in two regions identified as the SFG and left IPG. The SFG activation difference was interpreted to reflect decision-related mechanisms according to the Multiple Read-Out Model [Grainger, J., Jacobs, A.M., 1996. Orthographic processing in visual word recognition: A multiple read-out model. Psychological Review 103, 518-565]. The greater oxygenation response to words in the left IPG suggests that this region connects orthographic, phonological and semantic representations. A decrease of deoxygenated hemoglobin was observed to low frequency in comparison to high frequency words in a region identified as IFG. This region's sensitivity to word frequency suggests its involvement in grapheme-phoneme conversion, or its role during the selection of pre-activated semantic candidates.     

Differential diagnosis of frontal syndrome in patients with closed-head injuries

Background. A common sequela of head injury is "frontal syndrome", consisting in characteristic neurobehavioral disturbances. However, there is no ecologically valid research tool that would clearly indicate the presence of this syndrome. The goal of this article is to evaluate the authorized the Polish version of the Frontal Behavioral Inventory (FBInv), used to differentiate fronto-temporal dementia (FTD) from other dementias. Material and methods. The research involved 95 patients treated at the centers represented by the authors, divided into 3 groups: CHI, consisting of 39 patients with traumatic frontal lobe injuries; FTD, consisting of 28 patients with fronto-temporal dementia; and a control group of persons with post-traumatic depression without injury to the frontal lobes. The results were based on data obtained from caregivers in 24 categories of patient behavior covered by the FBInv. Results. We found important differences in total scores between patients with frontal syndrome from groups CHI and FTD, as against patients with post-traumatic depression. There are also noticeable differences between patients in group FTD and group CHI in terms of scores on particular test items. Conclusions. The FBInv in the authorized Polish version is both sensitive and specific in measuring neurobehavioral disturbances occurring in patients with post-traumatic damage to the changes in the behavioral and personality of these patients with the passage of time since injury or onset should be the topic of further research.     

The effect of medial frontal and posterior parietal demyelinating lesions on stroop interference

Functional imaging has consistently shown that attention-related areas of medial frontal and posterior parietal cortices are active during the attentional conflict induced by color naming in the presence of distracting words (Stroop task). Such studies, however, have provided few details of the correlational nature between observed regional brain activations and reaction time delay occurring in this situation. We analyzed the effect of medial frontal and posterior parietal lesions on the Stroop response in a group of patients with multiple sclerosis, a neurological disorder in which Stroop response speed is affected to varying degrees. Forty-five patients were assessed using a computer-presented verbal version of the Stroop task and specific MRI protocol. Demyelination areas were measured on five anatomical divisions of the medial frontal white matter and on white matter of the posterior parietal lobe. We found that a combination of frontal and parietal lesion measurements accounted for 45% of the Stroop interference time variance. Patients with more right frontal than left parietal demyelination showed slowed Stroop responses, whereas the predominance of lesions in the left posterior parietal region was associated with a reduced Stroop interference. These results may contribute to defining the specific participation of these attention-related brain areas in the conflict of attention represented by the Stroop paradigm. They also help to explain the variability of the Stroop effect in multiple sclerosis patients and suggest that the Stroop test does not assess just a single cognitive operation, but rather the combined effect of anatomically segregated neural processes.     

Cue validity modulates the neural correlates of covert endogenous orienting of attention in parietal and frontal cortex

Parietal brain regions have been implicated in reorienting of visuospatial attention in location-cueing paradigms when misleading advance information is provided in form of a spatially invalid cue. The difference in reaction times to invalidly and validly cued targets is termed the "validity effect" and used as a behavioral measure for attentional reorienting. Behavioral studies suggest that the magnitude of the validity effect depends on the ratio of validly to invalidly cued targets (termed cue validity), i.e., on the amount of top-down information provided. Using fMRI, we investigated the effects of a cue validity manipulation upon the neural mechanisms underlying attentional reorienting using valid and invalid spatial cues in the context of 90% and 60% cue validity, respectively. We hypothesized that increased parietal activation would be elicited when subjects need to reorient their attention in a context of high cue validity. Behaviorally, subjects showed significantly higher validity effects in the high as compared to the low cue validity condition, indicating slower reorienting. The neuroimaging data revealed higher activation of right inferior parietal and right frontal cortex in the 90% than in the 60% cue validity condition. We conclude that the amount of top-down information provided by predictive cues influences the neural correlates of reorienting of visuospatial attention by modulating activation of a right fronto-parietal attentional network.     

Evaluating the roles of the inferior frontal gyrus and superior parietal lobule in deductive reasoning: an rTMS study

This study used off-line repetitive transcranial magnetic stimulation (rTMS) to examine the roles of the superior parietal lobule (SPL) and inferior frontal gyrus (IFG) in a deductive reasoning task. Subjects performed a categorical syllogistic reasoning task involving congruent, incongruent, and abstract trials. Twenty four subjects received magnetic stimulation to the SPL region prior to the task. In the other 24 subjects, TMS was administered to the IFG region before the task. Stimulation lasted for 10min, with an inter-pulse frequency of 1Hz. We found that bilateral SPL (Brodmann area (BA) 7) stimulation disrupted performance on abstract and incongruent reasoning. Left IFG (BA 45) stimulation impaired congruent reasoning performance while paradoxically facilitating incongruent reasoning performance. This resulted in the elimination of the belief-bias. In contrast, right IFG stimulation only impaired incongruent reasoning performance, thus enhancing the belief-bias effect. These findings are largely consistent with the dual-process theory of reasoning, which proposes the existence of two different human reasoning systems: a belief-based heuristic system; and a logic-based analytic system. The present findings suggest that the left language-related IFG (BA 45) may correspond to the heuristic system, while bilateral SPL may underlie the analytic system. The right IFG may play a role in blocking the belief-based heuristic system for solving incongruent reasoning trials. This study could offer an insight about functional roles of distributed brain systems in human deductive reasoning by utilizing the rTMS approach.     

1例额颞顶叶脑梗死引起单侧肢体忽略自伤病人的护理

脑梗死是指局部脑组织包括神经细胞、胶质细胞和血管由于血液供应缺乏而发生的坏死[1]。额叶、颞叶、顶叶损害的病人常伴有一些精神症状:额叶病变表现精神活动方面的障碍,易出现痴呆、人格改变及病变对侧上肢强握与摸索反射;颞叶病变表现为幻嗅幻味、错觉幻觉、自动症及似曾相识症、旧事如新或生疏感、精神异常、内脏症状、情感异常及抽搐;顶叶病变时出现计算不能、不能识别手指、左右侧认识不能和书写不能;右侧顶叶邻近角回损害易出现自体认识不能:表现为不认识自己患侧身体的存在,认为左侧上下肢不是自己的;右侧顶叶邻近缘上回处损害出现…     

1例额颞顶叶脑梗死引起单侧肢体忽略自伤病人的护理

脑梗死是指局部脑组织包括神经细胞、胶质细胞和血管由于血液供应缺乏而发生的坏死。额叶、颞叶、顶叶损害的病人常伴有一些精神症状：额叶病变表现精神活动方面的障碍，易出现痴呆、人格改变及病变对侧上肢强握与摸索反射；颞叶病变表现为幻嗅幻味、错觉幻觉、自动症及似曾相识症、旧事如新或生疏感、精神异常、内脏症状、情感异常及抽搐；     

Detection of telomerase activity by the TRAP assay and its variants and alternatives

Telomerase activity is closely connected to problems of cellular immortality, proliferative capacity, differentiation, cancer and aging. Correspondingly, techniques for its detection have been essential for progress in telomere biology and are of still increasing importance in molecular diagnostics and therapy of cancer. This article reviews the development of the telomere repeat amplification protocol (TRAP) and its various modifications as the most widespread assay to detect and measure telomerase activity. Alternative possibilities of telomerase activity detection are also discussed which make it possible to omit the PCR-mediated amplification of telomerase products. These approaches are based on recent advances in highly sensitive detection systems.     

额叶p-mTOR异常表达与外伤性癫痫发生的相关研究

目的:探索外伤性癫痫(Posttraumatic epilepsy,PTE)发生与额叶p-mTOR异常表达的相关性。方法:将78只成年雄性SD大鼠分为正常对照组(A组)6只,生理盐水对照组(B组)和癫痫模型组(C组)各36只,C组右侧额叶注射FeCl_2造模。应用免疫组化技术检测造模后1h、24h、1周、2周、4周各组大鼠额叶皮质中p-mTOR(Ser2448)的动态表达。结果:A组额叶p-mTOR(Ser2448)表达的免疫组织化学染色,神经元胞质呈浅棕色,提示弱阳性表达;B组细胞染色程度较A组加深,p-mTOR(Ser2448)表达阳性细胞数增加;C组可见细胞结构紊乱,胞质呈明显的棕黄色,提示该蛋白在细胞质中呈强阳性表达。C组和B组比较,1h表达开始升高(t=-1.435,P=0.182),但差异无统计学意义,1周表达高峰(t=-4.073,P=0.002),2周降低(t=-2.614,P=0.026),4周时再次升高(t=-2.506,P=0.031),差异具有统计学意义(均P0.05)。结论:PTE的发病机制可能与mTOR信号通路上pmTOR(Ser2448)的表达异常增加有关。     

Is succinyldicholine the substrate of choice for the measurement of cholinesterase activity?

We have developed a succinyldicholine-based assay for serum cholinesterase (EC 3.1.1.8) to help establish whether patients with suspected sensitivity to drugs of this type have enzyme abnormalities that cannot be detected by conventional laboratory techniques. Although the method discriminates between cholinesterase activities of drug-sensitive and nonsensitive people as well as an assay involving propionylthiocholine does, it has not revealed cholinesterase abnormalities in patients who experienced prolonged apnea after succinyldicholine, in whom no enzyme defect could be demonstrated by other procedures. Of 50 individuals who were apneic for between 20 and 180 min, only one had a cholinesterase activity less than the mean for E1u homozygotes by more than 2.5 SD. We conclude that the number of patients who experience clinical problems due to enzyme abnormalities that at present go unrecognized is small. Consequently, although succinyldicholine might eventually become the substrate of choice for cholinesterase, its advantages over propionylthiocholine are not yet sufficient to encourage its use.     

Synergistic action of starch and honey against Pseudomonas aeruginosa in correlation with diastase number

To evaluate the synergistic action of starch on the antibacterial activity of honey against Pseudomonas aeruginosa, a comparative method of adding honey with and without starch to culture media was used. P. aeruginosa (ATCC 27853) was used to determine the minimum inhibitory concentration (MIC) of five varieties of honey. In a second step, lower concentrations of honey than the MIC were incubated with a set of concentrations of starch and then added to media to determine the minimum synergistic inhibitory concentration. The MIC for the five varieties of honey without starch against P. aeruginosa ranged between 15% and 26% (vol/vol). When starch was incubated with honey and then added to media, a significant MIC drop has been noticed with each variety and it ranged between 30.7% and 46.6%. No significant correlation has been established between the MIC drop and the diastase number.     

Differential roles for left inferior frontal and superior temporal cortex in multimodal integration of action and language

Several studies indicate that both posterior superior temporal sulcus/middle temporal gyrus (pSTS/MTG) and left inferior frontal gyrus (LIFG) are involved in integrating information from different modalities. Here we investigated the respective roles of these two areas in integration of action and language information. We exploited the fact that the semantic relationship between language and different forms of action (i.e. co-speech gestures and pantomimes) is radically different. Speech and co-speech gestures are always produced together, and gestures are not unambiguously understood without speech. On the contrary, pantomimes are not necessarily produced together with speech and can be easily understood without speech. We presented speech together with these two types of communicative hand actions in matching or mismatching combinations to manipulate semantic integration load. Left and right pSTS/MTG were only involved in semantic integration of speech and pantomimes. Left IFG on the other hand was involved in integration of speech and co-speech gestures as well as of speech and pantomimes. Effective connectivity analyses showed that depending upon the semantic relationship between language and action, LIFG modulates activation levels in left pSTS.This suggests that integration in pSTS/MTG involves the matching of two input streams for which there is a relatively stable common object representation, whereas integration in LIFG is better characterized as the on-line construction of a new and unified representation of the input streams. In conclusion, pSTS/MTG and LIFG are differentially involved in multimodal integration, crucially depending upon the semantic relationship between the input streams.     

2型糖尿病小鼠脑缺血再灌注额顶叶皮质因子变化及神经症状观察

目的探讨内皮素- 3和星形胶质细胞在糖尿病小鼠脑缺血再灌注损伤中的作用机制. 方法 将 66只成年雄性昆明小鼠按随机数字表法分为 5组单纯糖尿病( diabetes mellitus,DM)组 (n=6),糖尿病合并脑缺血再灌注( diatetes mellitus/ischemia-reperfusion,DM/IR)组( n=24),脑缺血再灌注 (ischemia-reperfusion,IR)组( n=24),假手术组( n=6),正常对照组( n=6).分别取小鼠额顶叶皮质进行免疫组化染色检测内皮素- 3和胶质纤维酸性蛋白( glial fibrillary acidic protein,GFAP)的表达. 结果对照组小鼠额叶、顶叶皮质Ⅲ-Ⅵ层可见少量内皮素- 3、 GFAP阳性细胞散在分布 ;糖尿病组内皮素- 3阳性神经元( 3 d时 IR, DM/IR组 75± 6, 96± 70)及 GFAP阳性细胞数( 3 d时 IR, DM/IR组 687± 17, 702± 35)均比对照组(内皮素- 3 28± 9; GFAP 183± 11)明显增多 (P< 0.01). 结论糖尿病是脑缺血再灌注损伤重要因素之一;内皮素- 3和星形胶质细胞激活可能是糖尿病小鼠神经细胞损伤加重恶化的机制之一.     

Failure to respond to influenza vaccine in the aged: correlation with B-cell number and function.

Failure to respond to influenza vaccination correlated with a decreased number and percentage of IgD-bearing PBL and a dampened lymphocyte response to PWM in a subset of healthy aged volunteers. These subjects had normal levels of serum immunoglobulins, intact T cell function, and normal numbers of E-rosetting cells.     

The left occipitotemporal system in reading: disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia

Developmental dyslexia is a severe reading disorder, which is characterized by dysfluent reading and impaired automaticity of visual word processing. Adults with dyslexia show functional deficits in several brain regions including the so-called "Visual Word Form Area" (VWFA), which is implicated in visual word processing and located within the larger left occipitotemporal VWF-System. The present study examines functional connections of the left occipitotemporal VWF-System with other major language areas in children with dyslexia. Functional connectivity MRI was used to assess connectivity of the VWF-System in 18 children with dyslexia and 24 age-matched controls (age 9.7-12.5 years) using five neighboring left occipitotemporal regions of interest (ROIs) during a continuous reading task requiring phonological and orthographic processing. First, the results revealed a focal origin of connectivity from the VWF-System, in that mainly the VWFA was functionally connected with typical left frontal and parietal language areas in control children. Adjacent posterior and anterior VWF-System ROIs did not show such connectivity, confirming the special role that the VWFA plays in word processing. Second, we detected a significant disruption of functional connectivity between the VWFA and left inferior frontal and left inferior parietal language areas in the children with dyslexia. The current findings add to our understanding of dyslexia by showing that functional disconnection of the left occipitotemporal system is limited to the small VWFA region crucial for automatic visual word processing, and emerges early during reading acquisition in children with dyslexia, along with deficits in orthographic and phonological processing of visual word forms.     

急诊骨外伤与气象要素的相关性分析

目的探讨急诊骨外伤与气象要素的关系。方法分析1999—2003年天津医院急诊骨外伤的变化特征并与同期气象资料进行单相关分析。筛选气象因子对骨科急诊量变化趋势作出预测。结果骨科急诊量春季4、5月份和秋季9、10月份比较高,与气象要素相关性较好。用气象因子组成的急诊骨外伤预测方程通过了可信度检验。结论骨科急诊量与气象要素密切相关,用气温、气压和降水量等主要气象因子对骨科急诊量作分级预测,有一定的实用性。     

系统性红斑狼疮活动的季节分布及其与气象因素的相关关系

目的探讨系统性红斑狼疮（SLE）活动的季节分布特点以及气象因素对狼疮活动的影响。方法回顾性分析湛江地区1997年1月至2006年12月共640例SLE活动患者的季节分布特点及其与气象因素（气温、湿度）的相关关系。结果在紫外线较弱的冬季,活动性SLE的比率（相对于总住院患者数）为3．89‰,显著高于紫外线较强的其他季节（春季：2．17‰,夏季：1．87‰,秋季：2．12‰）,均P〈0．001,尤以与夏季差异最显著;SLE活动病例分布与本地区月平均气温呈负相关（r=-0．352,P〈0．001）;SLE活动病例分布与本地区月平均湿度无相关性（r=0．053,P〉0．05）。结论SLE病情活动具有季节性,并与气温相关,原因需进一步研究。