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1.
Cheremushkin EA Kurova NS Kheĭfets IA 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2003,53(5):569-576
Analysis of coherence of cortical electric activity performed in 30 healthy subjects revealed changes in the spatial organization of cortical electric activity after listening the instruction, i.e., loading the explicit working memory with a sequence of operations of the cognitive task to be solved in the course of the experiment. Comparison of instructions presenting several cognitive tasks showed that greater load of the working memory is associated with higher coherence of cortical activity, especially, in the parietotemporal and occipital areas. 相似文献
2.
Rule-based category learning was examined in 4–11 year-olds and adults. Participants were asked to learn a set of novel perceptual categories in a classification learning task. Categorization performance improved with age, with younger children showing the strongest rule-based deficit relative to older children and adults. Model-based analyses provided insight regarding the type of strategy being used to solve the categorization task, demonstrating that the use of the task appropriate strategy increased with age. When children and adults who identified the correct categorization rule were compared, the performance deficit was no longer evident. Executive functions were also measured. While both working memory and inhibitory control were related to rule-based categorization and improved with age, working memory specifically was found to marginally mediate the age-related improvements in categorization. When analyses focused only on the sample of children, results showed that working memory ability and inhibitory control were associated with categorization performance and strategy use. The current findings track changes in categorization performance across childhood, demonstrating at which points performance begins to mature and resemble that of adults. Additionally, findings highlight the potential role that working memory and inhibitory control may play in rule-based category learning. 相似文献
3.
We have analyzed the impact of voluntary relaxation on the functional organization and the effectiveness of the voluntary prestimulus attention in performing cognitive tasks in adolescents at the ages of 12–13 and 13–14 years. The effectiveness of cognitive task performance (audio-verbal short-term memory) was estimated on the basis of the number of correctly remembered words. We have found that both age groups are characterized by reduced capacity for voluntary relaxation and its impact on the effectiveness of cognitive task performance. The analysis of the coherence function of EEG rhythmic components in a situation of voluntary attention focused on the performance of cognitive tasks showed no significant change in the interaction of the prefrontal cortex with other cortical areas during the switch from quiet wakefulness or post-relaxation state to the preparation to perform the task, which is typical of adults and young children. Our findings can be a result of sub-optimal functioning of voluntary regulation mechanisms and organization of activities during adolescence. 相似文献
4.
In adults and seven- to eight-year-old children, event-related potentials (ERPs) were analyzed during quiet observation and
detailed paired comparison of visual stimuli. In both age groups, we showed the differences in the initial stages (component
N1) of sensory analysis in these situations. In adults, an increase in the negativity during the initial stages of analysis
was observed in the caudal and central areas of the cortex during presentation of standard and test stimuli. In the frontal
areas of the cortex, an increase in the negative potential was observed only in ERPs induced by the test stimulus. In children,
an increase in the negativity at the initial phases of analysis of stimuli in the situation of working memory, as compared
to quiet observation, was confined to the caudal areas of the cortex. Differential curves that characterize analysis of standard
and test stimuli showed age-related differences in the initial and late phases of information processing under the conditions
of working memory. In adults, the differential curves that characterize analysis of the standard stimulus were represented
by negative phases, and the curves related to the test stimulus, by positive phases. In children, late phases of analysis
of the standard and test stimuli had smaller differences as compared to adults: the late positive wave was predominant in
the responses to both standard and test stimulus in the caudal areas of the cortex. In the frontal areas, there was no considerable
increase in the amplitude of the late positive wave in response to the test stimulus. This fact, together with the absence
of enhancement of initial negativity in the frontal areas, which reflects analysis of the test stimulus, indicates that the
prefrontal cortex plays a smaller role in the comparison of the memory trace with the current information in seven- to eight-year-old
children. The data obtained suggest that the central executive of working memory is not sufficiently mature in children aged
seven to eight years. 相似文献
5.
R. I. Machinskaya 《Human physiology》2006,32(1):20-29
A particular role was demonstrated for functional maturation of the frontothalamic system (FTS) of the brain in forming the cerebral organization of selective voluntary attention in ontogeny. Analysis of the coherence of the rhythmic components of the EEG α range in adults and seven-to eight-and nine-to ten-year-old children showed that, if the functional state of the control structures corresponds to the age, the formation of the neurophysiological mechanisms selectively modulating cortical activity and supporting selective tuning of the cerebral structures to the cognitive task is completed by the age of seven or eight years. Unlike adults, children demonstrated no interhemispheric features of the intercenter integration of cortical zones in the prestimulus period of voluntary attention. Children with a functionally immature FTS lacked selective specific integration of cortical zones in the pretuning period. The deficit of selective modulation of cortical activity in children with a functionally immature FTS is considered as the neurophysiological factor that delays the formation of voluntary attention and voluntary control of activity and, finally, leads to learning difficulties. 相似文献
6.
Kostandov EA Kurova NS Cheremushkin EA 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2002,52(5):531-538
Analysis of EEG coherence performed in 60 healthy adult subjects revealed some changes in the spatial organization of cortical electrical activity produced by complication of the context of cognitive performance (increasing the working memory load). Changes in the degree of coherence of cortical potentials within the local areas were observed already at the stage of the "operative readiness" immediately after the instruction, i.e., representation of the cognitive task sequence in the explicit working memory. The observed changes were different in the anterior (decrease in the degree of coherence) and posterior (increase in coherence) areas of the cortex. Context-related increase in the local coherence was more pronounced in the temporal, parietal, and occipital areas of the left hemisphere than in the right hemisphere. 相似文献
7.
Takahiro Osada Yusuke Adachi Kentaro Miyamoto Koji Jimura Rieko Setsuie Yasushi Miyashita 《PLoS biology》2015,13(6)
Neuroimaging and neurophysiology have revealed that multiple areas in the prefrontal cortex (PFC) are activated in a specific memory task, but severity of impairment after PFC lesions is largely different depending on which activated area is damaged. The critical relationship between lesion sites and impairments has not yet been given a clear mechanistic explanation. Although recent works proposed that a whole-brain network contains hubs that play integrative roles in cortical information processing, this framework relying on an anatomy-based structural network cannot account for the vulnerable locus for a specific task, lesioning of which would bring impairment. Here, we hypothesized that (i) activated PFC areas dynamically form an ordered network centered at a task-specific “functional hub” and (ii) the lesion-effective site corresponds to the “functional hub,” but not to a task-invariant “structural hub.” To test these hypotheses, we conducted functional magnetic resonance imaging experiments in macaques performing a temporal contextual memory task. We found that the activated areas formed a hierarchical hub-centric network based on task-evoked directed connectivity, differently from the anatomical network reflecting axonal projection patterns. Using a novel simulated-lesion method based on support vector machine, we estimated severity of impairment after lesioning of each area, which accorded well with a known dissociation in contextual memory impairment in macaques (impairment after lesioning in area 9/46d, but not in area 8Ad). The predicted severity of impairment was proportional to the network “hubness” of the virtually lesioned area in the task-evoked directed connectivity network, rather than in the anatomical network known from tracer studies. Our results suggest that PFC areas dynamically and cooperatively shape a functional hub-centric network to reallocate the lesion-effective site depending on the cognitive processes, apart from static anatomical hubs. These findings will be a foundation for precise prediction of behavioral impacts of damage or surgical intervention in human brains. 相似文献
8.
Are explicit versus implicit learning mechanisms reflected in the brain as distinct neural structures, as previous research indicates, or are they distinguished by brain networks that involve overlapping systems with differential connectivity? In this functional MRI study we examined the neural correlates of explicit and implicit learning of artificial grammar sequences. Using effective connectivity analyses we found that brain networks of different connectivity underlie the two types of learning: while both processes involve activation in a set of cortical and subcortical structures, explicit learners engage a network that uses the insula as a key mediator whereas implicit learners evoke a direct frontal-striatal network. Individual differences in working memory also differentially impact the two types of sequence learning. 相似文献
9.
Kostandov EA Cheremushkin EA 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2011,61(1):35-46
Using a cognitive set to emotional facial expression as a model, induced synchronization/desynchronization of the cortical theta- and alpha-activities were studied in adult healthy people under conditions of increased load on the working memory (additional task of the verbal stimuli recognition). A correlation was found between behavioral (increase in the set rigidity) and electrophysiological (decrease of the induced theta-rhythm synchronization) data. A hypothesis is suggested that the earlier revealed increase in the tonic prestimulus theta-activity and suppression of the poststimulus phasic activation of the cortico-hippocampal system are one of the mechanisms of the decrease in plasticity of the cognitive function of the emotional facial expression recognition under conditions of the increased load on the working memory. Reciprocal relations between two functional systems of the brain activity integration (cortico-hippocampal and fronto-thalamic) in the process of recognition of emotional facial expression are discussed. 相似文献
10.
Coherence at the frequency oftheta, alpha, and beta EEG rhythms was analyzed in 14 adults and 23 children of 7-8 years old while they performed cognitive tasks requiring an involvement of working memory (WM). We used the pair matching paradigm in which subjects had to match a pair of stimuli shown in succession in the central visual field. The pairs of verbal and visuo-spatial stimuli were mixed together and presented in a pseudo random order. Each pair was preceded by a warning signal that did not specify a modality of upcoming stimuli. We analyzed EEG segments recorded (i) in the rest condition, (ii) prior to the first (etalon) stimulus (maintenance of nonspecific voluntary attention), and (iii) prior to the second (test) stimulus (retention of information in WM). In the present study we focused on the regulatory functional components of WM, and therefore, the stimulus modality has not been taken into account. In adults, maintaining nonspecific voluntary attention was accompanied by an increase of the strength of theta-related functional coupling between medial areas of the frontal cortex and temporal cortical zones and by a strengthening of local beta-related functional connectivity in the anterior areas of the central cortex. In children, no such increase was found for theta-rhythm; for beta-rhythm the increase was limited to several short-range functional links. In adults, the retention of information in WM was accompanied by the growth in alpha coherence in distant fronto-parietal links, predominantly in the right hemisphere, while in children information retention was accompanied by the growth of theta-coherence in the inferio-temporal and parietal cortical regions. The results of the study point to a relative immaturity of the mechanisms of executive control of WM in children of 7-8 years old. 相似文献
11.
Martin Griebe Michael Amann Jochen G. Hirsch Lutz Achtnichts Michael G. Hennerici Achim Gass Kristina Szabo 《PloS one》2014,9(8)
Subcortical age-related white matter changes (ARWMC) are a frequent finding in healthy elderly people suggested to cause secondary tissue changes and possibly affecting cognitive processes. We aimed to determine the influence of the extent of ARWMC load on attention and working memory processes in healthy elderly individuals. Fourteen healthy elderly subjects (MMSE >26; age 55–80 years) performed three fMRI tasks with increasing difficulty assessing alertness, attention (0-back), and working memory (2-back). We compared activation patterns in those with only minimal ARWMC (Fazekas 0–1) to those with moderate to severe ARWMC (Fazekas 2–3). During the fMRI experiments, the study population showed activation in brain areas typically involved in attention and working memory with a recruitment of cortical areas with increasing task difficulty. Subjects with higher lesion load showed a higher activation at all task levels with only sparse increase of signal with increasing complexity. In the lower lesion load group, rising task difficulty lead to a significant and widely distributed increase of activation. Although the number of patients included in the study is small, these findings suggest that even clinically silent ARWMC may affect cognitive processing and lead to compensatory activation during cognitive tasks. This can be interpreted as a reduction of functional reserve and may pose a risk for cognitive decline in these patients. 相似文献
12.
Age-related characteristics of the systemic organization of intra- and interhemispheric interactions during a stereognostic
task (tactile shape recognition with the right or left hand) were studied in adults and children aged five to six, seven to
eight, and nine to ten years. A combined pattern of cortical interactions was found in adults. It was expressed in a considerable
enhancement of relationships between cortical bioelectric potentials compared to the baseline accompanied by a substantial
increase in the intensity of the systemic interactions between anterior and posterior cortical areas. This pattern was revealed
by both coherence and cross-correlation analyses of the electroencephalogram (EEG). In the EEGs of children, the enhancement
of interhemispheric relationships was observed at an age as early as five to six years and was the highest in seven- to eight-year-old
children, whereas the increase in the cross-correlation of cortical bioelectric potentials in the frontal—occipital direction
developed gradually, approaching the definitive level typical of adults by the age of nine to ten years. The results suggest
that the central mechanisms of stereognosis, a function important for manual and occupational activities, gradually develop
during postnatal ontogeny. Heterochronic involvement of intra- and interhemispheric interactions in the performance of stereognostic
task may be related to gradual, heterochronic myelination of commissural and associative pathways. 相似文献
13.
Aging has a multi-faceted impact on brain structure, brain function and cognitive task performance, but the interaction of these different age-related changes is largely unexplored. We hypothesize that age-related structural changes alter the functional connectivity within the brain, resulting in altered task performance during cognitive challenges. In this neuroimaging study, we used independent components analysis to identify spatial patterns of coordinated functional activity involved in the performance of a verbal delayed item recognition task from 75 healthy young and 37 healthy old adults. Strength of functional connectivity between spatial components was assessed for age group differences and related to speeded task performance. We then assessed whether age-related differences in global brain volume were associated with age-related differences in functional network connectivity. Both age groups used a series of spatial components during the verbal working memory task and the strength and distribution of functional network connectivity between these components differed across the age groups. Poorer task performance, i.e. slower speed with increasing memory load, in the old adults was associated with decreases in functional network connectivity between components comprised of the supplementary motor area and the middle cingulate and between the precuneus and the middle/superior frontal cortex. Advancing age also led to decreased brain volume; however, there was no evidence to support the hypothesis that age-related alterations in functional network connectivity were the result of global brain volume changes. These results suggest that age-related differences in the coordination of neural activity between brain regions partially underlie differences in cognitive performance. 相似文献
14.
Functional connectivity between the prefrontal cortex and the temporal and temporo-parieto-occipital cortices in the process of preparing for the recognition of fragmented images were analyzed in adults (n = 26) and seven- to eight-year-old children (n = 20).The evaluations of the imaginary part of the complex-valued coherency for the EEG alpha-rhythm (Jα) were used as an index for the strength of cortico-cortical interactions. The Jα value was analyzed in the following three experimental conditions corresponding to different stages of readiness for visual recognition: (1) nonspecific attention holding in the period preceding a warning stimulus (S1); (2) focused attention in the interval preceding a not-yet-recognized target stimulus (S2) and (3) pretuning preceding a recognized stimulus (S3). Adult subjects tended towards a growing level of functional connectivity in α-rhythm in progressing from attention holding to focused attention preceding the emergence of a target stimulus, but children, on the contrary, demonstrated a decreasing trend. Comparing the Jα values in the subgroups of adults and children who showed the highest recognition scores in the solution of cognitive tasks helped reveal age-specific patterns in the rearrangements of cortico-cortical functional connectivity in α-rhythm in the left and right hemispheres at different stages of readiness for recognizing incomplete images. In adults, the maximal Jα values were found in the left hemisphere in the interval preceding the recognition of a target image. At this stage of pretuning, the Jα values at the leads in the left hemisphere in adults significantly exceeded those in children. The Jα values for the right hemisphere in adults were maximal during focused prestimulus attention when the image was not yet recognized and these values were significantly higher than in children under the same experimental conditions. Children showed maximal Jα values in both hemispheres during nonspecific attention. The specifics of functional connectivity observed between the prefrontal, temporal and temporo-parieto-occipital cortices in seven- to eight-year-old children during functional pretuning to the recognition of fragmented images are considered to reflect the relative immaturity of neurophysiological mechanisms underlying the voluntary attention and working memory in children of this age group. 相似文献
15.
Coherence at the frequency of θ, α, and β EEG rhythms was analyzed in 14 adults and 23 children of 7–8 years old while they
performed cognitive tasks requiring an involvement of working memory (WM). We used the pair matching paradigm in which subjects
had to match a pair of stimuli shown in succession in the central visual field. The pairs of verbal and visuo-spatial stimuli
were mixed together and presented in a pseudo random order. Each pair was preceded by a warning signal that did not specify
a modality of upcoming stimuli. We analyzed EEG segments recorded (i) in the rest condition, (ii) prior to the first (reference)
stimulus (maintenance of nonspecific voluntary attention), and (iii) prior to the second (test) stimulus (retention of information
in WM). In the present study we focused on the regulatory functional components of WM, and therefore, the stimulus modality
has not been taken into account. In adults, maintaining nonspecific voluntary attention was accompanied by an increase of
the strength of θ-related functional coupling between medial areas of the frontal cortex and temporal cortical zones and by
a strengthening of local β-related functional connectivity in the fronto-central areas of the cortex. In children, no such
increase was found for θ rhythm; for β rhythm the increase was limited to several short-range functional links. In adults,
the retention of information in WM was accompanied by the growth in α coherence in distant fronto-parietal links, predominantly
in the right hemisphere, while in children information retention was accompanied by the growth of θ coherence in the inferio-temporal
and parietal cortical regions. The results of the study point to a relative immaturity of the mechanisms of executive control
of WM in children of 7–8 years old. 相似文献
16.
Changes in the recognition of facial expression and spatial synchronization of the cortical electrical activity of the θ-
and α-potentials caused by load on working memory were studied in healthy adults by introducing an additional semantic or
visuospatial task into the context of experiment with a visual set. An increase in the number of erroneous recognitions of
facial stimuli in the form of assimilative illusions was revealed in both types of the additional task. The analysis of the
function of coherence of the low-frequency α-potentials indicates (8–10 Hz) a decrease in this situation in the number of
connections in the frontal cortical divisions with other cortical zones, which is regarded as a lesser involvement of the
frontal system of selective attention in set-forming and set-shifting for an emotionally negative facial expression. Spatial
synchronization of the θ-activity (4–7 Hz) with an increase in the load on working memory changes ambiguously in different
cortical structures: it decreases in the system of the fronto-temporal connections of the right hemisphere; in the other cortical
areas, especially in the left hemisphere, and in the system of interhemispheric connections it substantially increases. The
facts confirming the hypothesis that the fronto-thalamic and cortico-hippocampal systems are the two key formations involved
in changes in the plasticity of cognitive sets for facial expression are discussed. 相似文献
17.
The development of cortical functions and the capacity of the mature brain to learn are largely determined by the establishment and maintenance of neocortical networks. Here we address the human development of long-range connectivity in primary visual and motor cortices, using well-established behavioral measures--a Contour Integration test and a Finger-tapping task--that have been shown to be related to these specific primary areas, and the long-range neural connectivity within those. Possible confounding factors, such as different task requirements (complexity, cognitive load) are eliminated by using these tasks in a learning paradigm. We find that there is a temporal lag between the developmental timing of primary sensory vs. motor areas with an advantage of visual development; we also confirm that human development is very slow in both cases, and that there is a retained capacity for practice induced plastic changes in adults. This pattern of results seems to point to human-specific development of the "canonical circuits" of primary sensory and motor cortices, probably reflecting the ecological requirements of human life. 相似文献
18.
Using spectral Granger causality (GC) we identified distinct spatio-temporal causal connectivity (CC) patterns in groups of control and epileptic children during the execution of a one-back matching visual discrimination working memory task. Differences between control and epileptic groups were determined for both GO and NOGO conditions. The analysis was performed on a set of 19-channel EEG cortical activity signals. We show that for the GO task, the highest brain activity in terms of the density of the CC networks is observed in α band for the control group while for the epileptic group the CC network seems disrupted as reflected by the small number of connections. For the NOGO task, the denser CC network was observed in θ band for the control group while widespread differences between the control and the epileptic group were located bilaterally at the left temporal-midline and parietal areas. In order to test the discriminative power of our analysis, we performed a pattern analysis approach based on fuzzy classification techniques. The performance of the classification scheme was evaluated using permutation tests. The analysis demonstrated that, on average, 87.6 % of the subjects were correctly classified in control and epileptic. Thus, our findings may provide a helpful insight on the mechanisms pertaining to the cognitive response of children with well controlled epilepsy and could potentially serve as “functional” biomarkers for early diagnosis. 相似文献
19.
A leading notion is that language skill acquisition declines between childhood and adulthood. While several lines of evidence indicate that declarative ("what", explicit) memory undergoes maturation, it is commonly assumed that procedural ("how-to", implicit) memory, in children, is well established. The language superiority of children has been ascribed to the childhood reliance on implicit learning. Here we show that when 8-year-olds, 12-year-olds and young adults were provided with an equivalent multi-session training experience in producing and judging an artificial morphological rule (AMR), adults were superior to children of both age groups and the 8-year-olds were the poorest learners in all task parameters including in those that were clearly implicit. The AMR consisted of phonological transformations of verbs expressing a semantic distinction: whether the preceding noun was animate or inanimate. No explicit instruction of the AMR was provided. The 8-year-olds, unlike most adults and 12-year-olds, failed to explicitly uncover the semantic aspect of the AMR and subsequently to generalize it accurately to novel items. However, all participants learned to apply the AMR to repeated items and to generalize its phonological patterns to novel items, attaining accurate and fluent production, and exhibiting key characteristics of procedural memory. Nevertheless, adults showed a clear advantage in learning implicit task aspects, and in their long-term retention. Thus, our findings support the notion of age-dependent maturation in the establishment of declarative but also of procedural memory in a complex language task. In line with recent reports of no childhood advantage in non-linguistic skill learning, we propose that under some learning conditions adults can effectively express their language skill acquisition potential. Altogether, the maturational effects in the acquisition of an implicit AMR do not support a simple notion of a language skill learning advantage in children. 相似文献
20.
目的:针对不同COMT基因型健康青年被试,进行连续3-back任务1h共12Block,探讨健康成人数字工作记忆能力变化情况。方法:将112名健康青年分组抽取出18名不同基因型作为被试,利用视觉事件相关电位P3来观测被试连续工作记忆任务中COMT基因多态型与脑皮层电生理的关系。结果:Val/Val基因型的被试P3波幅显著高于Val/Met基因型(P<0.01),但和Met/Met基因型被试的波幅无差异。结论:Val/Met基因型被试关联着最差的工作记忆任务的成绩,被试者的P3波幅和3-back任务成绩成正相关。 相似文献