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1.
Objective： To assess functional relationship by calculating inter- and intra-hemispheric electroencephalography （EEG） coherence at rest and during a working memory task of patients with mild cognitive impairment （MCI）. Methods： The sample consisted of 69 subjects： 35 patients （n = 17 males, n = 18 females; 52-71 years old） and 34 normal controls （n = 17 males, n = 17 females; 51 -63 years old）. Mini-mental state examination （MMSE） of two groups revealed that the scores of MCI patients did not differ significantly from those of normal controls （P〉0.05）. In EEG recording, subjects were performed at rest and during working memory task. EEG signals from F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 electrode pairs are resulted from the inter-hemispheric action, and EEG signals from F3-C3, F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs are resulted from the intra-hemispheric action for delta （1.0-3.5 Hz）, theta （4.0-7.5 Hz）, alpha-1 （8.0-10.0 Hz）, alpha-2 （10.5-13.0 Hz）, beta-1 （13.5-18.0 Hz） and beta-2 （18.5-30.0 Hz） frequency bands. The influence of inter- and intra-hemispheric coherence on EEG activity with eyes closed was examined using fast Fourier transformation from the 16 sampled channels. Results： During working memory tasks, the inter- and intra-hemispheric EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group （P〈0.05）. However, there was no significant difference in inter- and intra-hemispheric EEG coherences between two groups at rest. Conclusion： Experimental results comprise evidence that MCI patients have higher degree of functional connectivity between hemispheres and in hemispheres during working condition, It suggests that MCI may be associated with compensatory processes during working memory tasks between hemispheres and in hemispheres. Moreover, failure of normal cortical connections may exist in MCI patients.  相似文献   

2.
Objective: The functional relationship between calculated alpha band spectral power and inter-/intra-hemispheric coherence during a three-level working memory task of patients with mild cognitive impairment (MCI) was investigated. Methods: Subjects included 35 MCI patients according to the DSM-IV criteria (mean age: 62.3, SD: 6.5) and 34 healthy controls (mean age: 57.4, SD: 4.0) were selected from the community at large. All subjects performed a simple calculation and recall task with three levels of working memory load while electroencephalograph (EEG) signal was recorded. The spectral EEG power was computed over alpha1 (8.0～10.0 Hz) and alpha2 (10.5～13.0 Hz) frequency bands and was compared between rest stage and working memory processing stage by two-way ANOVA. Post hoc testing analyzed the differences between each two levels of working memory load during task processing. The inter-hemisphere EEG coherence of frontal (F3-F4), central (C3-C4), parietal (P3-P4), temporal (T5-T6) as well as occipital (O1-O2) was compared between MCI patients and normal controls. The EEG signals from F3-C3, F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs resulted from the intra-hemispheric action for alpha1 and alpha2 frequency bands. Result: There was significantly higher EEG power from MCI patients than from normal controls both at rest and during working memory processing. Significant differences existed between rest condition and three-level working memory tasks (P<0.001). The inter-and intra-hemispheric coherence during working memory tasks showed a "drop to rise" tendency compared to that at rest condition. There was significantly higher coherence in MCI patients than in the controls. When task difficulties increased, the cortical connectivity of intra-hemispheric diminished while the inter-hemispheric connectivity dominantly maintained the cognitive processing in MCI patients. Conclusion: The results of the present study indicate that the alpha frequency band may be the characteristic band in distinguishing MCI patients from normal controls during working memory tasks. MCI patients exhibit greater inter-hemispheric connectivity than intra-hemispheric connectivity when memory demands increase. MCI patients mobilize a compensatory mechanism to maintain the processing effectiveness while the processing efficiency is reduced.  相似文献   

3.
To investigate inter- and intra-hemispheric electroencephalography (EEG) coherence at rest and during photic stimulation of patients with Alzheimer‘s disease (AD). Thirty-five patients (12 males, 23 females; 52-64 y) and 33 sex- and age-matched controls (12 males, 21 females; 56-65 y) were recruited in the present study. EEG signals from C3-C4, P3-P4, TS-T6 and O1-O2 electrode pairs resulted from the inter-hemispheric action, and EEG signals from C3-P3, C4-P4, P3-O1, P4-O2, C3-O1, C4-O2, TS-O1 and T6-O2 electrode pairs resulted from the intra-hemispheric action. The influence of inter- and intra-hemispheric coherence on EEG activity with eyes closed was examined, using fast Fourier transformation from the 16 sampled channels. The frequencies of photic stimulation were fixed at 5, l0 and 15 Hz, respectively. The general decrease of AD patients in inter- and intra-hemispheric EEG coherence was more significant than that of the normal controls at the resting EEG, with most striking decrease observed in the alpha-1 (8.0-9.0 Hz) and alpha-2 (9.5-12.5 Hz) bands. During photic stimulation, inter- and intra-hemispheric EEG coherences of the AD patients having lower values in the alpha (9.5-10.5 Hz) band than those of the control group. It suggests that under stimulated and non-stimulated conditions, AD patients had impaired inter- and intra-hemispheric functional connections, indicating failure of brain activation in alpha-related frequency.  相似文献   

4.
In order to investigate the characteristics of sensorimotor cortex during motor execution(ME), voluntary, stimulated and imaginary finger flexions were performed by ten volunteer subjects. Electroencephalogram(EEG) data were recorded according to the modified 10-20 International EEG System. The patterns were compared by the analysis of the motion-evoked EEG signals focusing on the contralateral(C3) and ipsilateral(C4) channels for hemispheric differences. The EEG energy distributions at alpha(8—13 Hz), beta(14—30 Hz) and gamma(30—50 Hz) bands were computed by wavelet transform(WT) and compared by the analysis of variance(ANOVA). The timefrequency(TF) analysis indicated that there existed a contralateral dominance of alpha post-movement event-related synchronization(ERS) pattern during the voluntary task, and that the energy of alpha band increased in the ipsilateral area during the stimulated(median nerve of wrist) task. Besides, the contralateral alpha and beta event-related desynchronization(ERD) patterns were observed in both stimulated and imaginary tasks. Another significant difference was found in the mean power values of gamma band(p0.01)between the imaginary and other tasks. The results show that significant hemispheric differences such as alpha and beta band EEG energy distributions and TF changing phenomena(ERS/ERD) were found between C3 and C4 areas during all of the three patterns. The largest energy distribution was always at the alpha band for each task.  相似文献   

5.
Using time‐frequency analysis techniques to investigate the event‐related low‐frequency (delta: 0.5–4 Hz; theta: 4–8 Hz) activity of auditory event‐related potentials (ERPs) data of highly and average intelligent children, 18 intellectually gifted children, and 18 intellectually average children participated the present study. Present findings show that intellectually gifted children had significantly larger delta activity than their normal peers in mismatch negativity (MMN) component, while in P3a component, which originates from stimulus‐driven frontal attention mechanisms during task processing, intellectually gifted children had both significantly larger delta and theta activities than their normal peers. The present findings further supported that low‐frequency brain activity could be regarded as the basis of intelligence and cognitive functions, and spectral EEG time‐frequency analysis technique should be used to explore some new aspects of brain activity relating to intelligence.  相似文献   

6.
目的旨在探索音乐节拍对大脑活动主要区域信息加工过程中的脑电波谱变异.方法采用自编的音乐播放软件给被试分别播放(42、65、120 BPM)3种音乐节拍的65 dB音乐,每种节拍曲目播放5 min,并采集16脑区的脑电信号进行离线分析.结果 (1)与安静状态相比播放音乐时被试在7个波段的脑电波谱功率显著降低;播放音乐时脑电波谱重心频率向低频段移动,表明疲劳程度增加;(2)改变音乐节拍显著降低α1波频段的功率而增加α2波频段的功率;(3)从频段功率占比看,加快音乐节拍节奏增加高频段脑电波活动,降低节拍节奏增加低频段活动而降低高频段脑电波活动.结论音乐节拍显著影响脑电波谱功率变异,65 BPM的中等节奏音乐有利于注意力集中和放松休息,120 BPM快节奏音乐有利于激活唤醒水平,加快运动,改变音乐节拍增加注意负荷,消耗更多的心理加工资源,其意义有待于进一步探索.  相似文献   

7.
In this study, the inhibitory effect ofjujuboside A (JuA) on a penicillin sodium (Na-PCN) induced hyperactivity model was investigated. Cortical EEG (electroencephalogram) and the concentration of hippocampal Glutamate (Glu) were monitored simultaneously in vivo as indicators of rat's excitatory state. Power spectral density (PSD) and gravity frequency of PSD were calculated. JuA (0.05 g/L and 0.1 g/L) inhibited the EEG excitation effect caused by Na-PCN by increasing the power of δ1 and δ2bands (P＜0.01 vs model) and lowering the gravity frequency of PSD (P＜0.01 vs model). JuA also remarkably reduced the Glu elevation induced by Na-PCN (P＜0.05 vs model). Diazepam also depressed Glu concentration and lowered the gravity frequency,but it showed a different EEG pattern in increased β2-activity (P＜0.01 vs model). EEG excitation caused by Na-PCN correlated with Glu elevation during the first hour. Neurophysiological inhibitory effects of JuA and diazepam were more persistent than their Glu inhibitoty effects.  相似文献   

8.
The present study examined the role of verbal working memory (memory span and tongue-twister), two-character Chinese pseudoword reading (two tasks), rapid automatized naming (RAN) (letters and numbers), and phonological segmentation (deletion of rimes and onsets) in inferential text comprehension in Chinese in 31 less competent comprehenders compared with 37 reading comprehension control students and 23 chronological age controls. It was hypothesized that the target students would perform poorly on these cognitive and linguistic tasks as compared with their controls. Furthermore, verbal working memory and pseudoword reading would explain a considerable amount of individual variation in Chinese text comprehension. RAN would have a nonsignificant role in text comprehension. Structural equation analyses and hierarchical multiple regression analyses generally upheld these hypotheses. Our findings support current literature of the role of verbal working memory in reading comprehension found in English. The results, however, suggest differential role of the constructs and the tasks in reading comprehension and provide some answers for comprehension impairment in Chinese students.  相似文献   

9.
Children (n = 122) and adults (n = 200) with dyslexia completed rapid automatic naming (RAN) letters, rapid automatic switching (RAS) letters and numbers, executive function (inhibition, verbal fluency), and phonological working memory tasks. Typically developing 3rd (n = 117) and 5th (n = 103) graders completed the RAS task. Instead of analyzing RAN/RAS results the usual way (total time), growth mixture modeling assessed trajectories of successive times for naming 10 symbols in each of five rows. For all three samples and both RAN and RAS, two latent classes were identified. The “faster” class performed slowly on the first row and increased time by small increments on subsequent rows. The “slower” latent class performed more slowly on the first row, and children, but not adults, increased time by larger increments on subsequent rows. For children, both the initial row (automaticity index) and slope (sustained controlled processing index) of the trajectory differentiated the classes. For adults, only the initial row separated the classes. The longest time was on row 3 for RAN and row 4 for RAS. For the typically developing 5th graders, close in age to the children with dyslexia, the trajectories were flatter than for children with dyslexia and only the slower class (4%) showed the peak on row 4. For children with dyslexia, inhibition predicted RAN slope within the slower latent class and phonological working memory predicted RAS slope for both latent classes. For adults with dyslexia, inhibition and phonological working memory differentiated both latent classes on RAN intercept and RAS slope. Taken together, RAN, which may assess the phonological loop of working memory, and RAS, which may assess the central executive in working memory, may explain the timing deficit in dyslexia in sustaining coordinated orthographic-phonological processing over time. This research was supported by Grant Ns. P50 33812 and R01 HD25858 from the National Institute of Child Health and Human Development, Virginia W. Berninger, PI.  相似文献   

10.
We described a female patient with insulinoma who experienced recurrent episodes of automatism, confusion and convulsion. Furthermore, her electroencephalography (EEG) findings resembled the pattern in complex partial seizures with secondary generalization. The interictal EEG showed spikes and sharp waves, as well as focal slowing over the left temporal lobe, and the ictal EEG revealed generalized spikes and sharp waves associated with diffused slowing. She was initially misdiagnosed as pharmacoresistant epilepsy. After the insulinoma was found and surgically removed, her EEG turned normal and she was seizure-free during the 4-year follow-up. This report highlights the need for careful reassessment of all seizures refractory to medication, even for the patients associated with epileptiform discharges on EEG.  相似文献   

11.
Working memory has been proposed as an important component of reading and arithmetic skills. The development of working memory was studied in normally achieving and subtypes of learning disabled children. The performance of reading disabled (RD), arithmetic disabled (ARITHD), and attentional deficit disordered (ADD) children, age 7-13, was compared to normal achievers (NA) on 2 working memory tasks, 1 involving sentences and the other involving counting. There was a significant growth of working memory as a function of age. In addition, the RD children had significantly lower scores on both tasks. The ARITHD children had significantly lower scores only on the Working Memory--Counting task, and the ADD group had scores similar to the normally achieving children except at the youngest age level in the Working Memory--Sentences task. Thus, a reading disability appears to involve a generalized deficit in working memory. Children with an arithmetic disability do not have a generalized language deficit but have a specific working memory deficit in relation to processing numerical information. As children with ADD did not have deficits in these tasks, working memory may not have significant attentional components. An important component of the development of reading and computational arithmetic skills appears to be the growth of working memory for language and numerical information.  相似文献   

12.
Working memory refers to a mental workspace, involved in controlling, regulating, and actively maintaining relevant information to accomplish complex cognitive tasks (e.g. mathematical processing). Despite the potential relevance of a relation between working memory and math for understanding developmental and individual differences in mathematical skills, the nature of this relationship is not well-understood. This paper reviews four approaches that address the relation of working memory and math: 1) dual task studies establishing the role of working memory during on-line math performance; 2) individual difference studies examining working memory in children with math difficulties; 3) studies of working memory as a predictor of mathematical outcomes; and 4) longitudinal studies of working memory and math. The goal of this review is to evaluate current information on the nature of the relationship between working memory and math provided by these four approaches, and to present some of the outstanding questions for future research.  相似文献   

13.
Neurodevelopmental Correlates of Theory of Mind in Preschool Children   总被引：1，自引：1，他引：0  
Baseline electroencephalogram (EEG) data were collected from twenty-nine 4-year-old children who also completed batteries of representational theory-of-mind (RTM) tasks and executive functioning (EF) tasks. Neural sources of children's EEG alpha (6–9 Hz) were estimated and analyzed to determine whether individual differences in regional EEG alpha activity predicted children's RTM performance, while statistically controlling for children's age and EF skills. Results showed that individual differences in EEG alpha activity localized to the dorsal medial prefrontal cortex (dMPFC) and the right temporal–parietal juncture (rTPJ) were positively associated with children's RTM performance. These findings suggest that the maturation of dMPFC and rTPJ is a critical constituent of preschoolers' explicit theory-of-mind development.  相似文献   

14.
Twenty‐nine grade‐matched 4th–8th‐grade males, 12 with attention‐deficit/hyperactivity disorder (ADHD) (age M= 12.2 years, SD= 1.48), and 17 without (age M= 11.5, SD= 1.59), completed two working memory tasks (digit span and the Simon game) and three long‐term episodic memory tasks (a personal event memory task, story memory task, and picture recognition task). In line with clinical observations, children with ADHD performed worse than peers on all working memory tasks, but performed as well as or better than peers on long‐term episodic tasks, demonstrating particularly detailed memory for personally experienced past events. Participants' parents also completed questionnaires about their children's memories in daily life. Parents rated children with ADHD lower than children without ADHD on working and semantic memory (e.g., remembering names, spelling, and math), but rated them as high or higher on memory for events. Implications for theory and educational practice are discussed.  相似文献   

15.
The relations between changes in the scalp-recorded electroencephalogram (EEG) and the development of the ability to perform successfully 2 cognitive tasks attributed to frontal lobe functioning were examined in 13 infants from 7 to 12 months of age. Infants successful in performing the A-not-B task with increasingly longer delays across the second half of the first year of life showed changes in power in scalp-recorded brain electrical activity in the frontal region and an increase in anterior/posterior EEG coherence. Infants with rapid mastery of object retrieval did not differ in frontal EEG development from infants who exhibited the normal developmental progression in object retrieval performance. In a task examining inhibition of reaching to a novel toy, there were no differences in frontal EEG as a function of performance. Results from a cross-sectional sample revealed similar findings. These data confirm work with nonhuman primates on the importance of maturation of frontal cortex in the successful performance on certain tasks (A-not-B), but do not confirm nonhuman primate data on the importance of frontal cortex for other tasks (object retrieval). The data also suggest that the electroencephalogram may be useful as a noninvasive measure of central nervous system development during the first year of life.  相似文献   

16.
眼跳任务常用于研究额叶纹状体环路的机能,使用延迟眼跳任务可有效分离抑制空间工作记忆,深入探究注意缺陷多动障碍(ADHD)儿童的执行功能损伤.48名儿童(ADHD-I型11人,ADHD-C型19人,对照组18人)完成2种实验任务:正向眼跳和延迟眼跳.结果发现:(1)ADHD儿童存在抑制功能损伤,延迟眼跳中对照组错误率的成绩优势非常显著,延迟时间的加长使ADHD组的错误率显著提高,但不影响对照组错误率.(2)ADHD儿童存在一定的空间工作记忆损伤,延迟眼跳中ADHD组有较差的精确性,且延迟时间越长组间差异越显著.(3)ADHD儿童有较长的反应时和较慢的眼跳速度.  相似文献   

17.
We studied the performance in three genres of Chinese written composition (narration, exposition, and argumentation) of 158 grade 4, 5, and 6 poor Chinese text comprehenders compared with 156 good Chinese text comprehenders. We examined text comprehension and written composition relationship. Verbal working memory (verbal span working memory and operation span working memory) and different levels of linguistic tasks—morphological sensitivity (morphological compounding and morphological chain), sentence processing (syntax construction and syntax integrity), and text comprehension (narrative and expository texts)—were used to predict separately narrative, expository, and argumentation written compositions in these students. Grade for grade, the good text comprehenders outperformed the poor text comprehenders in all tasks, except for morphological chain. Hierarchical multiple regression analyses showed differential contribution of the tasks to different genres of writing. In particular, text comprehension made unique contribution to argumentation writing in the poor text comprehenders. Future studies should ask students to read and write parallel passages in the same genre for better comparison and incorporate both instructional and motivational variables.  相似文献   

18.
Mental imagery generation is essential in the retrieval and storage of knowledge. Previous studies have indicated that the holistic properties of mental imagery generation can be evaluated more easily than the partial properties. However, the relationship between partial and holistic mental imagery generations has not been clearly demonstrated. To address this issue, we designed a task to investigate the changes in the spectrum of the electroencephalogram (EEG) during partial or holistic imagery generation. EEG signals were obtained from 18 healthy subjects, and a statistical measure of spectral dynamics between two EEG signals in per frequency band was performed. Additionally, a bicoherence spectrum analysis was used to detect the phase coupling within these two imagery conditions. Our results indicated that EEG of the partial imagery appeared earlier and stronger than that of the holistic imagery in the theta (5–8 Hz) range in a time window around 220 to 300 ms after cue onset, and a slight decrease in the alpha (8–12 Hz) band was observed at around 270 ms. The scalp topography of these changes in the theta and alpha bands distributed overall significantly in the frontal and central-temporal areas. The significant phase coupling within two conditions was remarkable at high frequency. From these results, we infer that there are complex relations between partial and holistic imageries. The generation of partial mental imagery is not a subprocess of holistic imagery, but it is relevant to holistic imagery and requires correct modification from the holistic information.  相似文献   

19.
Metamemory in children with autism   总被引：2，自引：0，他引：2  
Five experiments are reported comparing metamemory abilities in children with autism, age- and language-matched mentally retarded children, and language-matched young normal controls. The mean language age of the participants in Experiment 1 was approximately 6 years, in Experiments 2, 3, and 4 approximately 8 years, and in Experiment 5 approximately 9 years. All the children were given one or more false belief tests. Experiment 1 assessed the children's understanding that a task variable (list length) and a person variable (age) will affect their own and others' performances on an immediate auditory-verbal recall task. Experiment 2 assessed the ability to utilize category cues in a picture recall task. Experiments 3 and 4 assessed the ability to verbalize strategies used in a memory span test and in one retrospective and two prospective memory situations. Experiment 5 assessed the children's knowledge and understanding of another person's memory. On the basis of available evidence and theory, we predicted that the children with autism would be impaired on all the metamemory tasks and that impairment would be associated with failure on tests of false belief. Our predictions were not supported. The children with autism were not impaired on any of the metamemory tasks, although they were less likely than controls to make spontaneous use of memory strategies involving other people. Unexpectedly few of the children failed the false belief tasks. These results are discussed in relation to theories concerning primary psychological deficits underlying autism.  相似文献   

20.
Working memory deficits in children with special educational needs   总被引：1，自引：0，他引：1  
Susan Gathercole and Susan Pickering, of the Department of Experimental Psychology at the University of Bristol, compared the working memory abilities of children recognised by their schools as having special educational needs with those of children making normal curricular progress. All three components of the working memory model of Baddeley and Hitch (1974) were assessed by administering a working memory test battery when the children were aged seven and eight years. Children recognised as having special educational needs had marked impairments on the working memory measures, and in particular on the tasks tapping the central executive. These findings suggest that poor working memory capacity may be a key feature in unexpected failure to make normal curricular progress, and also indicate the potential utility of working memory assessments in identifying children at risk of low achievement in school in future years.  相似文献   

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