Motivation and semantic context affect brain error-monitoring activity: an event-related brain potentials study

During speech production, we continuously monitor what we say. In situations in which speech errors potentially have more severe consequences, e.g. during a public presentation, our verbal self-monitoring system may pay special attention to prevent errors than in situations in which speech errors are more acceptable, such as a casual conversation. In an event-related potential study, we investigated whether or not motivation affected participants' performance using a picture naming task in a semantic blocking paradigm. Semantic context of to-be-named pictures was manipulated; blocks were semantically related (e.g., cat, dog, horse, etc.) or semantically unrelated (e.g., cat, table, flute, etc.). Motivation was manipulated independently by monetary reward. The motivation manipulation did not affect error rate during picture naming. However, the high-motivation condition yielded increased amplitude and latency values of the error-related negativity (ERN) compared to the low-motivation condition, presumably indicating higher monitoring activity. Furthermore, participants showed semantic interference effects in reaction times and error rates. The ERN amplitude was also larger during semantically related than unrelated blocks, presumably indicating that semantic relatedness induces more conflict between possible verbal responses.     

银杏叶提取物对脑组织及脑神经细胞活性的保护作用

目的:银杏叶提取物主要成分黄酮苷、萜烯内酯和单体内酯等对心血管系统,脑循环,血液及神经等方面作用机制和疗效已基本肯定,现就银杏叶提取物对脑组织及神经损伤保护作用的研究进行综述。资料来源:应用计算机检索Medline数据库1994-01/2004-12期间的相关文章,检索词为“Ginkgobilobaextract”,限定文章语言种类为英文;同时计算机检索中国期刊全文数据库、万方数据库1995-01/2003-12期间的相关文章,检索词为″银杏叶提取物″,限定文章语言种类为中文。资料选择:对资料进行初审,纳入银杏叶提取物作用于脑细胞及神经细胞的相关药理机制,临床运用及其有效成分,对脑缺血缺氧,水肿的保护以及大脑皮质层的记忆功能丧失和脑部病变引起的帕金森病的防治相关的文献。排除标准:综述类文献和重复研究。资料提炼:共收集到44篇关于银杏叶提取物对脑组织及神经损伤保护作用的文献,纳入为银杏叶提取物作用于脑细胞及神经细胞的相关药理机制,临床运用及其有效成分,对脑缺血缺氧,水肿的保护以及大脑皮质的记忆功能丧失和脑部病变引起的帕金森病的防治相关的文献19篇。排除综述类文献和重复研究25篇。资料综合:①银杏叶提取物对脑血栓的保护性作用:银杏叶提取物可明显抑制缺血再灌注损伤所致的组织纤溶酶原激活因子抑制因子Ⅰ的升高,调节纤维蛋白溶酶过程,防止血栓形成。②银杏叶提取物对脑缺血缺氧、水肿的保护作用:银杏叶提取物中黄酮苷、萜烯内脂和单体具有多种药理活性,对脑缺血缺氧、水肿保护作用与抗血小板活化因子、抗自由基和改善脑血管循环的作用密切相关。③银杏叶提取物对大脑记忆力的影响:银杏叶提取物主要是通过促进大脑海马胆碱的再摄取,减少M型胆碱受体和α2肾上腺素受体及递质的丢失,从而发挥改善学习和记忆能力的功能。④银杏叶提取物对帕金森病的防治作用:其机制是通过保护残存的损伤侧黑质神经元,使得纹状体多巴胺的减少得以控制,并保持在一定的水平;银杏内脂抑制纹状体多巴胺的代谢,从而升高多巴胺的水平。⑤银杏叶提取物对脑神经的保护作用:银杏叶提取物可能通过抑制神经细胞一氧化氮的产生、抑制嗜中性粒细胞所介导的炎症反应、直接对抗谷氨酸受体等保护脑神经。结论:银杏叶提取物和单体的研究在动物实验和心血管疾病的运用性研究上取得了广泛的成果,对于激活脑组织及神经损伤的细胞,改善脑血管循环,治疗和预防脑部某些疾病有一定的作用。     

银杏叶提取物对脑组织及脑神经细胞活性的保护作用

目的：银杏叶提取物主要成分黄酮苷、萜烯内酯和单体内酯等对心血管系统，脑循环，血液及神经等方面作用机制和疗效已基本肯定，现就银杏叶提取物对脑组织及神经损伤保护作用的研究进行综述。 资料来源：应用计算机检索Medline数据库1994-01／2004—12期间的相关文章，检索词为“Ginkgo biloba extract”，限定文章语言种类为英文；同时计算机检索中国期刊全文数据库、万方数据库1995-01／2003—12期间的相关文章，检索词为”银杏叶提取物”，限定文章语言种类为中文。 资料选择：对资料进行初审，纳入银杏叶提取物作用于脑细胞及神经细胞的相关药理机制，临床运用及其有效成分，对脑缺血缺氧，水肿的保护以及大脑皮质层的记忆功能丧失和脑部病变引起的帕金森病的防治相关的文献。排除标准：综述类文献和重复研究。 资料提炼：共收集到44篇关于银杏叶提取物对脑组织及神经损伤保护作用的文献，纳入为银杏叶提取物作用于脑细胞及神经细胞的相关药理机制，临床运用及其有效成分，对脑缺血缺氧，水肿的保护以及大脑皮质的记忆功能丧失和脑部病变引起的帕金森病的防治相关的文献19篇。排除综述类文献和重复研究25篇。 资料综合：①银杏叶提取物对脑血栓的保护性作用：银杏叶提取物可明显抑制缺血再灌注损伤所致的组织纤溶酶原激活因子抑制因子Ⅰ的升高，调节纤维蛋白溶酶过程，防止血栓形成。②银杏叶提取物对脑缺血缺氧、水肿的保护作用：银杏叶提取物中黄酮苷、萜烯内脂和单体具有多种药理活性，对脑缺血缺氧、水肿保护作用与抗血小板活化因子、抗自由基和改善脑血管循环的作用密切相关。③银杏叶提取物对大脑记忆力的影响：银杏叶提取物主要是通过促进大脑海马胆碱的再摄取，减少M型胆碱受体和α2肾上腺紊受体及递质的丢失，从而发挥改善学习和记忆能力的功能。④银杏叶提取物对帕金森病的防治作用：其机制是通过保护残存的损伤侧黑质神经元，使得纹状体多巴胺的减少得以控制，并保持在一定的水平；银杏内脂抑制纹状体多巴胺的代谢，从而升高多巴胺的水平。⑤银杏叶提取物对脑神经的保护作用：银杏叶提取物可能通过抑制神经细胞一氧化氮的产生、抑制嗜中性粒细胞所介导的炎症反应、直接对抗谷氨酸受体等保护脑神经。 结论：银杏叶提取物和单体的研究在动物实验和心血管疾病的运用性研究上取得了广泛的成果，对于激活脑组织及神经损伤的细胞，改善脑血管循环，治疗和预防脑部某些疾病有一定的作用。     

Oscillatory brain activity before and after an internal context change--evidence for a reset of encoding processes

Prior behavioral work has shown that changing context during encoding can influence long-term memory performance. The present study examined the neural correlates of such context effects by analyzing oscillatory brain activity during the encoding of words, both before and after a context change. Participants studied two lists of items and, after the presentation of List 1, were either cued to change their internal context through a simple imagination task, or not. Replicating the behavioral work, the change in context led to forgetting of the first list (List 1) and to memory enhancement of the second (List 2). Measuring EEGs during encoding of the two lists, the context change was found to affect oscillatory brain activity. Whereas an increase of theta and alpha power from List-1 to List-2 encoding was found when the context was left unchanged, a slight theta and alpha power decrease was found when the context was changed. In addition, median split analysis revealed that alpha power during List-2 encoding was related to the enhancement effect of the context change. The results suggest that a change in internal context can lead to a reset of encoding processes, thus pointing to a crucial role of encoding processes in context-dependent memory.     

The effect of experimental muscle pain on the background electrical brain activity.

The purpose of this project was to investigate whether specific effects in the background activity of the brain associated with the experience of pain can be depicted by means of quantitative electroencephalography (EEG). Lasting pain was induced by intramuscular infusion of hypertonic saline. The infusion was titrated to maintain pain for a sufficient time to obtain enough data for meaningful analysis. In a first study on 12 subjects, using a single, blind, repeated measures design with randomization of the administration of isotonic (0.9%) and hypertonic (5%) saline, and with subjects unaware of the fact that one substance was isotonic saline, a statistically significant pain response could be attributed to the administration of hypertonic saline. In a second study on 19 subjects, again using a randomized repeated measures design, topographic EEG measures were examined with respect to experimentally induced pain and pain from memory. Prior to each of these experimental stages, baseline recordings were obtained to satisfy the requirement of the crossover design. In addition to the common frequency bands used in EEG, we also obtained data in the frequency range of 35-100 Hz. The short-term variability of the selected EEG measures and their suitability as a sample estimate were assessed by computing the coefficient of variation from all selected epochs of a given subject at baseline. When compared to baseline, spectral analyzed EEG measures during experimental pain demonstrated statistically significant increases in the beta and 35-100 Hz frequency ranges, most notably at the temporal recording sites. There was no statistically significant difference between the EEG measures for (1) experimental pain vs. pain from memory, and (2) the 2 baseline recordings. The great variability in the topographical aspect of the between-subject response was interpreted as being strongly suggestive of the contamination of EEG measures by phenomena attributed to the jaw, facial and scalp musculature. In fact, Pearson correlation coefficients, as high as 0.92, were found between measures in the frequency band of 35-100 Hz and the beta frequency range. The unexplained variance in the heightened beta cortical power density can be attributed to the vigilance scanning of pain processes. Due to the fact that the statistically significant effect of pain on the topographic EEG measures were not different from imagined pain, we concluded that these effects are non-specific for pain.     

The effect of context on skill acquisition and transfer.

OBJECTIVE: A major concern of occupational therapy is the identification of context characteristics that optimize performance. The purpose of this study was to examine the effect of context on skill acquisition and transfer. METHOD: Forty college students without disabilities (12 men, 28 women) were randomly assigned to the task of learning to use chopsticks in either a natural or a simulated context. Each participant practiced 60 trials in an acquisition phase on 1 day and was tested on a transfer task 24 hr after the acquisition phase. Their performances in the acquisition and transfer phases were measured with the variables of success rate and reaching kinematics. RESULTS: The natural context elicited significantly larger improvement of success rate in the acquisition phase and a significantly higher success rate in the transfer phase than the simulated context. No major difference was found in kinematic variables between the two contexts. CONCLUSION: These results suggested the use of natural contexts to facilitate the outcome of motor skill learning.     

Broca-Sulzer效应和时间背景效应的共同机制

目的:探讨两种明度知觉时间效应——Broca-Sulzer效应和时间背景效应的关系及机制。方法:实验于2006-06-10在中南民族大学脑认知科学研究室完成。选择5名中南民族大学硕士研究生作为受试者,均视力正常或矫正视力正常,自愿参加实验。刺激呈现在校准过的22"Ⅱyama HM204DT显示器上,屏幕距被试58cm,屏幕的背景为黑色,亮度小于1cd/m2,刷新频率为200Hz。①第1个实验,刺激是两个物理亮度相等的闪光刺激,它们出现在一个固定点的两边,一个呈现时间短暂,另一个呈现时间较长,要求被试观察哪个闪光刺激更亮。考察闪光刺激的物理亮度(3,6,12cd/m2)和短暂闪光刺激的呈现时间(30,60,120ms)对时间背景效应现象的影响。②第2个实验,采用单眼和双眼分离两种观察方式,使得刺激呈现单眼呈现15ms,单眼呈现30ms,双眼呈现30ms3种情况,在刺激呈现结束后,要求被试报告闪光刺激明暗关系。结果:5名被试均进入结果分析。①实验1结果:闪光刺激亮度为3,6,12cd/m2时,观察到短暂闪光刺激比较长闪光刺激亮的频度分别为9%,87%,100%;短暂闪光刺激的呈现时间为30,60,120ms时,观察到短暂闪光刺激比长闪光刺激亮的频度分别为23%,94%,26%。②实验2结果:当左右视野相对区域融合后,双眼融合成的30ms闪光刺激和单眼呈现15ms的闪光刺激亮度感觉差不多,单眼30ms的闪光刺激最亮。结论:①在高亮度条件下,容易发生时间背景效应,即短暂闪光刺激的明度会随其发生延迟的渐增而显得更亮。②当短暂闪光刺激持续时间在50~100ms,容易发生时间背景效应。③时间背景效应所要求的闪光刺激的亮度和持续时间,都与Broca-Sulzer效应的产生条件相一致,说明这两种效应高度相关,且具有共同的机制,它们相关的亮度信息加工区域位于双眼信息汇聚之前。     

Disablement and the social context of daily activity

Background and purpose: There is an increasing need to get insight into the social and societal impact of chronic conditions on a person's life, i.e. person-perceived handicap. The purpose of this study is to report how current handicap questionnaires assess handicap. Method: A literature search using both Medline and the database of the Dutch Institute of Allied Health Professions (NPi) was conducted for handicap questionnaires. Questionnaires were included if addressing handicaps or life roles, environmental influences and social consequences of a disease. Excluded were questionnaires focusing on only impairments, disabilities or quality of life. Results and conclusion: 20 questionnaires were identified. Handicap is not uniformly defined in these questionnaires. Based on different concepts, the various questionnaires encompass different domains and different aspects are emphasized in similar domains. Fourteen questionnaires assess societyperceived handicaps, and do not address the life roles, care needs or individual problem-experience. Six questionnaires are to some extent person-perceived, but a generic person-perceived handicap questionnaire could not be identified. It is concluded that development of a generic person-perceived handicap questionnaire is essential for adequate assessment of needs, outcome, and relevance of rehabilitation interventions from the individual's point of view.     

Art therapy and behavior development in the context of hospitalization

Hospitalization may have negative effects on child development and behavior. Thus the aim of this work was to evaluate the behavior during the hospitalization of 7- to 10-year-old children, before and after art therapy intervention. It was proposed a quasi-experimental plan with a control group (n=10) and a group that was submitted to art therapy intervention (n=10). Results show that these interventions were effective in improving the behavior of the children. Hospitals can also be stimulating environments for children if they offer them health care practices that go beyond the disease.     

The sociocultural context of korean american men's smoking behavior

The purpose of this article is to explore the sociocultural context wherein Korean male immigrants learned and maintained smoking behavior. Participants were 11 current and 11 former cigarette smokers who resided in New York City. The participants attended one of four focus groups and talked about their experiences of smoking initiation, changes in smoking behavior over time, smoking in Korea and the United States, strategies used for smoking cessation, and suggestions for a smoking cessation program. The focus group interviews were audiotaped and transcribed verbatim. Themes were identified from answers to the five topic questions and then compared across the four focus groups. Smoking is a common thread in Korean men's social world and a prime component of Korean men's gender identity. In contrast, smoking in the United States is increasingly being stigmatized.     

Interaction of COMT val158met and externalizing behavior: relation to prefrontal brain activity and behavioral performance

A promising approach in neuroimaging studies aimed at understanding effects of single genetic variants on behavior is the study of gene-trait interactions. Variation in the catechol-O-methyl-transferase gene (COMT) is associated with the regulation of dopamine levels in the prefrontal cortex and with cognitive functioning. Given the involvement of dopaminergic neurotransmission in externalizing behavior, a trait characterized by impulsivity and aggression, especially in men, externalizing (as a trait) may index a set of genetic, environmental, and neural characteristics pertinent to understanding phenotypic effects of genetic variation in the COMT gene. In the current study, we used a gene-trait approach to investigate effects of the COMT val(158)met polymorphism and externalizing on brain activity during moments involving low or high demands on cognitive control. In 104 male participants, interference-related activation depended conjointly on externalizing and val(158)met: stronger activation in the dorsal anterior cingulate and lateral prefrontal cortex was found for val/val individuals with high trait externalizing while stronger activation in cingulate motor areas and sensorimotor precuneus was found for met/met individuals with low externalizing. Our results suggest that the val/val genotype, coupled with high levels of trait externalizing, lowers the efficiency of stimulus conflict resolution, whereas the met/met genotype, coupled with low levels of externalizing, lowers the efficiency of response selection.     

Effects of familiar voices on brain activity

This study aimed to examine the extent to which a familiar voice influences brain activity. Participants were nine healthy female volunteers aged 21-34 years old (with a mean age of 25.78 ± 4.04 years). Brain activity was recorded during periods of silence, familiar and unfamiliar voices. Electroencephalographic data were collected and analyzed using a frequency rate set at 5 min. To account for emotional influences imbedded into the contents of the voice stimuli, both the voice of a familiar family member and the voice of a stranger were used to record a well-known Japanese fairy tale, 'Momotaro'. Results revealed that listening to familiar voices increased the rate of the β band (13-30 Hz) in all four brain areas (F3, F4, C3 and C4). In particular, increased activity was observed at F4 and C4. Findings revealed that in study, participants' familiar voices activated cerebral functioning more than unfamiliar voices.     

Lateralization of brain activity during lower limb joints movement. An fMRI study

Studies of unilateral finger movement in right-handed subjects have shown asymmetrical patterns of activation in primary motor cortex and subcortical regions. In order to investigate the existence of an analogous pattern during lower limb joints movements, functional magnetic resonance imaging (fMRI) was used. Eighteen healthy, right leg dominant volunteers participated in a motor block design study, performing unilateral right and left repetitive knee, ankle and toes flexion/extension movements. Aiming to relate lower limb joints activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was also assessed. All movements were auditory paced at 72 beats/min (1.2 Hz). Brain activation during movement of the nondominant joints was more bilateral than during the same movement performed with the dominant joints. Finger movement had a stronger lateralized pattern of activation in comparison with lower limb joints, implying a different functional specialization. Differences were also evident between the joints of the lower limb. Ankle and toes movements elicited the same extend of MR signal change in the majority of the examined brain regions, whereas knee joint movement was associated with a different pattern. Finally, lateralization index in primary sensorimotor cortex and basal ganglia was significantly affected by the main effect of dominance, whereas the lateralization index in cerebellum was significantly affected by the joint main effect, demonstrating a lateralization index increase from proximal to distal joints.     

人参总皂甙对大鼠脑缺血时脑微血管及脑组织中一氧化氮合酶的影响及脑保护作用

目的:探讨人参总皂甙(SPG)对大鼠局灶性脑缺血的保护作用及其机制.方法:用线栓法制备大鼠大脑中动脉闭塞(MCAO)模型,用放射性同位素法测定大鼠脑微血管及脑组织中一氧化氮合酶(NOS)活性,用氯化三苯四唑(TTC)染色,用图像分析仪测定脑梗死体积,显微镜下观察脑组织的病理学变化.结果:中药保护4 h(I4G)组脑微血管中NOS活性[(12.9±11.7)nmol·mg-1·min-1]明显低于假手术(S)组[(42.1±21.0)nmol·mg-1·min-1,P<0.01]及脑缺血4 h(I4)组[(103.8±34.9)nmol·mg-1·min-1,P<0.001],脑组织NOS活性[纹状体(47.5±11.2)nmol·mg-1·min-1,海马(65.3±8.9)nmol·mg-1·min-1]明显高于I4组[纹状体(36.6±7.4)nmol·mg-1·min-1,海马(49.9±9.7)nmol·mg-1·min-1,P<0.05和P<0.01],并伴随脑梗死体积减小(P<0.01)及脑组织病理变化减轻.结论:SPG对MCAO大鼠有明显的脑保护作用,其机制可能是通过减少脑微血管中NOS活性及使脑组织中的NOS活性维持在一定水平上而实现的.