Cross-association analysis of EEG and EMG signals according to movement intention state

Rehabilitation within three months plays a significant role in the recovery of damaged motor functions following the onset of a stroke. To increase the effectiveness of rehabilitation, it is important to perform rehabilitative exercises with movement intention. This study analyzed the association between electroencephalogram (EEG) and electromyogram (EMG) signals in healthy individuals in an attempt to verify the differences between the two signals in corticomuscular connectivity as well as the time delay in the flow of information in accordance with the presence of movement intention. To examine the relationship between the brain and muscles, coherence and mutual information analyses were performed on the EEG signals in the motor cortex and EMG signals in the flexor digitorum superficialis muscle during grasping training. Coherence and mutual information between EEG and EMG signals were significantly higher and the time delay of information flow was shorter when subjects performed active exercise with movement intention than when they performed passive exercise without movement intention. These findings could be applied to the rehabilitation of stroke patients to develop a rehabilitative training system with heightened effectiveness through verification of the presence of movement intention in the patients.     

Central neuronal motor behaviour in skilled and less skilled novices – Approaching sports-specific movement techniques

Research on motor behavioural processes preceding voluntary movements often refers to analysing the readiness potential (RP). For this, decades of studies used laboratory setups with controlled sports-related actions. Further, recent applied approaches focus on athlete-non-athlete comparisons, omitting possible effects of training history on RP. However, RP preceding real sport-specific movements in accordance to skill acquisition remains to be elucidated.Therefore, after familiarization 16 right-handed males with no experience in archery volunteered to perform repeated sports-specific movements, i.e. 40 arrow-releasing shots at 60 s rest on a 15 m distant standard target. Continuous, synchronised EEG and right limb EMG recordings during arrow-releasing served to detect movement onsets for RP analyses over distinct cortical motor areas. Based on attained scores on target, archery novices were, a posteriori, subdivided into a skilled and less skilled group. EMG results for mean values revealed no significant changes (all p > 0.05), whereas RP amplitudes and onsets differed between groups but not between motor areas. Arrow-releasing preceded larger RP amplitudes (p < 0.05) and later RP onsets (p < 0.05) in skilled compared to less skilled novices. We suggest this to reflect attentional orienting and greater effort that accompanies central neuronal preparatory states of a sports-specific movement.     

观点采择在内隐情绪加工中的调节作用

观点采择对人们加工情绪具有明显的影响。已有研究发现人们对负性情绪信息存在加工偏向, 且观点采择对外显情绪的加工具有调节作用。但观点采择如何影响内隐情绪的加工尚不清楚。为了考察观点采择对内隐情绪加工的影响, 当前研究要求被试分别通过自我视角和他人视角完成情绪图片(中性图片和负性图片)的形状辨别任务, 同时记录其脑电活动。成分分析的结果显示, 与他人视角条件相比, 自我视角条件下加工负性信息引发了更大的额部及中央的N200 (180~220 ms)和顶区的LPC (267~567 ms)波幅。相位锁定的时频分析结果显示, 刺激呈现后0 ms 至300 ms时间窗口内, 在自我视角条件下, 负性信息的加工引发了显著增大的theta (4~8 Hz)节律的能量活动。成分分析和时频分析的结果均表明, 自我视角条件对负性信息加工具有启动效应, 他人视角条件则抑制了对负性信息的加工, 说明观点采择对内隐情绪加工具有调节作用, 反映了人不仅能够区分环境中潜在的危险信息, 而且能通过观点采择区分自我与他人。     

基于神经生理学的疼痛测量

疼痛是一种受多重因素影响的复杂主观感受。临床上,疼痛测量主要依赖于患者的主观评价。然而,这种传统的疼痛测量方法具有多方面的局限。近年来,研究者借助生理记录、脑电和功能磁共振等技术,揭示疼痛的神经生理、心理机制,挖掘与疼痛相关的神经生理指标,进而构建有效、客观和精确的疼痛评价体系。在基础研究和临床实践中,这些技术有望弥补传统疼痛测量方法的不足,从而极大推动疼痛测量及其治疗等相关领域研究的发展。     

The earliest electrophysiological correlate of visual awareness?

To examine the neural correlates and timing of human visual awareness, we recorded event-related potentials (ERPs) in two experiments while the observers were detecting a grey dot that was presented near subjective threshold. ERPs were averaged for conscious detections of the stimulus (hits) and nondetections (misses) separately. Our results revealed that hits, as compared to misses, showed a negativity around 180-350 ms at occipital and posterior temporal sites. It was followed by a positive wave after 400-500 ms, peaking at parietal sites. These correlates were not affected by a manipulation of attention. The early negativity, called 'visual awareness negativity' (VAN), may be a general, primary electrophysiological correlate of visual awareness. The present data show that it can be observed in response to appearance of a stimulus in visual awareness and that it generalizes across different manipulations of stimulus visibility.     

Children’s Affect Expression and Frontal EEG Asymmetry: Transactional Associations with Mothers’ Depressive Symptoms

Although parents and children are thought to influence one another's affect and behavior, few studies have examined the direction of effects from children to parents, particularly with respect to parental psychopathology. We tested the hypothesis that children's affective characteristics are associated with the course of mothers' depressive symptoms. Children's affect expression was observed during a series of mother-child interaction tasks, and children's resting frontal electroencephalogram (EEG) asymmetry was assessed in a psychophysiology laboratory. Mothers' depressive symptoms were assessed at two time points, approximately one year apart, at the mother-child interaction visits. Depressive symptoms increased over time for mothers with a history of childhood-onset depression whose children exhibited right frontal EEG asymmetry. Depressive symptoms were associated with high child negative affect at both time points for mothers whose children exhibited right frontal EEG asymmetry. Cross-lagged models with a subset of participants provided some evidence of both parent-to-child and child-to-parent directions of effects. Findings suggest that akin to other interpersonal stressors, children's affective characteristics may contribute to maternal depressive symptoms.     

Syntax as a reflex: neurophysiological evidence for early automaticity of grammatical processing

It has been a matter of debate whether the specifically human capacity to process syntactic information draws on attentional resources or is automatic. To address this issue, we recorded neurophysiological indicators of syntactic processing to spoken sentences while subjects were distracted to different degrees from language processing. Subjects were either passively distracted, by watching a silent video film, or their attention was actively streamed away from the language input by performing a demanding acoustic signal detection task. An early index of syntactic violations, the syntactic Mismatch Negativity (sMMN), distinguished between grammatical and ungrammatical speech even under strongest distraction. The magnitude of the early sMMN (at <150ms) was unaffected by attention load of the distraction task. The independence of the early syntactic brain response of attentional distraction provides neurophysiological evidence for the automaticity of syntax and for its autonomy from other attention-demanding processes, including acoustic stimulus discrimination. The first attentional modulation of syntactic brain responses became manifest at a later stage, at approximately 200ms, thus demonstrating the narrowness of the early time window of syntactic autonomy. We discuss these results in the light of modular and interactive theories of cognitive processing and draw inferences on the automaticity of both the cognitive MMN response and certain grammar processes in general.     

Right frontal EEG asymmetry and behavioral inhibition in infants of depressed mothers

Recent studies have shown associations between maternal psychopathology and inhibited behaviors in infants. Moreover, physiological factors have been identified as affecting the continuity of behavioral inhibition across childhood. The purpose of the present study was to examine electroencephalogram (EEG) activity and inhibited behavior in 12-month-old infants of depressed versus non-depressed and mothers. Repeated measures MANOVAs indicated that the infants of mothers with stable psychopathology had greater relative right frontal EEG asymmetry, a pattern that typically accompanies greater negative affect and greater withdrawal behaviors. Infants of affectively ill mothers also showed more proximal behaviors toward a stranger and a novel toy than infants of well mothers, but fewer non-proximal behaviors toward their mothers. These results are discussed within a framework of behavioral inhibition for infants exposed to early psychopathologies in their mothers.     

Patterns of brain-electrical activity during declarative memory performance in 10-month-old infants

This study of infant declarative memory concurrently examined brain-electrical activity and deferred imitation performance in 10-month-old infants. Continuous electroencephalogram (EEG) measures were collected throughout the activity-matched baseline, encoding (modeling) and retrieval (delayed test) phases of a within-subjects deferred imitation task. Infants were divided into two memory performance groups based on the exhibition of ordered-recall after a 24-h delay. Whereas no group differences were found in EEG collected during encoding, performance-group differences in EEG were present during retrieval. Infants who successfully displayed ordered-recall showed a pattern of increasing EEG from baseline to task at anterior temporal scalp locations, whereas infants showing no ordered-recall displayed no changes in EEG from baseline to task. These findings are discussed with respect to the biobehavioral developments underlying declarative memory abilities.     

Effects of unilateral hippocampus-amygdala-partial temporal lobe resection on auditory EEG/MEG responses: a case study

Auditory orienting and discrimination were studied with combined multi-channel EEG and MEG recordings in a patient with unilateral amygdala-hippocampus-partial temporal lobe resection of the right hemisphere. The results revealed abnormalities of habituation in alerting- and orienting-related responses, and discrimination-related responses, elicited by auditory stimulation contralateral to the resected cerebral hemisphere. These results give support to the notions about the role of the amygdala and hippocampus in alerting and orienting, respectively, and of the temporal cortex in auditory discrimination.