Electroencephalographic intercentral interaction as a reflection of normal and pathological human brain activity

The authors summarized EEG findings and defined the nature of the intercentral EEG relationships in different functional states in healthy subjects and patients with organic cerebral pathology, based on a coherence analysis. Similar EEG characteristics in healthy individuals were identified: an anterior-posterior gradient of average coherence levels, the type of cortical-subcortical relationships in anterior cerebral structures. Right- and left-handed individuals showed frequent and regional differences in EEG coherence, which mainly reflected specificity of intracortical relationships. Development and regression of pathology in right-and left-handed individuals with organic brain lesions were thought to be caused by these differences. Lesions of regulatory structures (diencephalic, brain stem and limbic structures) provoked a more diffused kind of changes of intercentral relationships, in contrast to cortical pathology. These changes tended to reciprocate. The dynamic nature of intercentral relationships and their interhemispheric differences was revealed when changing functional states of the brain (increase and decrease of functional level) in healthy individuals and patients with organic cerebral pathology in the process of conscious and psychic activity restoration. Changing activity predominance of certain regulatory structures was considered one of the most important factors determining the dynamic nature of EEG coherence.     

Brain-imaging studies of posttraumatic stress disorder

Brain-imaging studies of posttraumatic stress disorder (PTSD) have rapidly increased in recent years. Structural studies have identified potential smaller volumes of the hippocampus of traumatized and/or PTSD subjects. Functional activation studies have implicated hyperactive or altered functioning of brain regions, such as the amygdala and the insula, and a failure to engage emotional regulatory structures, such as the medial prefrontal and anterior cingulate cortex. Recent neurochemical investigations have suggested that neuromodulatory systems (eg, gamma-aminobutyric acid, micro-opioid) may underlie these aberrant brain activation patterns. This article reviews the literature on structural, functional, and neurochemical brain-imaging studies of PTSD.     

Impairments of speech fluency in Lewy body spectrum disorder

Few studies have examined connected speech in demented and non-demented patients with Parkinson’s disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured narrative speech sample in order to characterize impairments of speech fluency and to determine the factors contributing to reduced speech fluency in these patients. Both demented and non-demented PD patients exhibited reduced speech fluency, characterized by reduced overall speech rate and long pauses between sentences. Reduced speech rate in LBSD correlated with measures of between-utterance pauses, executive functioning, and grammatical comprehension. Regression analyses related non-fluent speech, grammatical difficulty, and executive difficulty to atrophy in frontal brain regions. These findings indicate that multiple factors contribute to slowed speech in LBSD, and this is mediated in part by disease in frontal brain regions.     

EEG phase synchronization during semantic unification relates to individual differences in children’s vocabulary skill

As we listen to speech, our ability to understand what was said requires us to retrieve and bind together individual word meanings into a coherent discourse representation. This so‐called semantic unification is a fundamental cognitive skill, and its development relies on the integration of neural activity throughout widely distributed functional brain networks. In this proof‐of‐concept study, we examine, for the first time, how these functional brain networks develop in children. Twenty‐six children (ages 4–17) listened to well‐formed sentences and sentences containing a semantic violation, while EEG was recorded. Children with stronger vocabulary showed N400 effects that were more concentrated to centroparietal electrodes and greater EEG phase synchrony (phase lag index; PLI) between right centroparietal and bilateral frontocentral electrodes in the delta frequency band (1–3 Hz) 1.27–1.53 s after listening to well‐formed sentences compared to sentences containing a semantic violation. These effects related specifically to individual differences in receptive vocabulary, perhaps pointing to greater recruitment of functional brain networks important for top‐down semantic unification with development. Less skilled children showed greater delta phase synchrony for violation sentences 3.41–3.64 s after critical word onset. This later effect was partly driven by individual differences in nonverbal reasoning, perhaps pointing to non‐verbal compensatory processing to extract meaning from speech in children with less developed vocabulary. We suggest that functional brain network communication, as measured by momentary changes in the phase synchrony of EEG oscillations, develops throughout the school years to support language comprehension in different ways depending on children's verbal and nonverbal skill levels.     

Lateralization of prosody during language production: a lesion study

To examine brain lateralization of prosody during speech, the sentence production of six right-hemisphere-lesion patients and five left-hemisphere-lesion patients was compared to that of seven normal controls using a question-answer paradigm. The task required the prosodic realization of two different syntactic structures under conditions of wide and narrow focus. Acoustical analyses were carried out on F0 and time structure. These analyses revealed a preserved ability in patients to express differences in syntactic structure via prosody. However, there were deficits in distinguishing narrow focus from wide focus. Whereas both right- and left-hemisphere lesions caused impairments in the realization of F0, time structure was mainly impaired in left-hemisphere patients. Therefore, the present results from language production support functional as well as cue-dependent hypotheses of the lateralization of prosodic processing in the brain.     

Function and Dysfunction of Prefrontal Brain Circuitry in Alcoholic Korsakoff’s Syndrome

The signature symptom of alcohol-induced persisting amnestic disorder, more commonly referred to as alcoholic Korsakoff's syndrome (KS), is anterograde amnesia, or memory loss for recent events, and until the mid 20th Century, the putative brain damage was considered to be in diencephalic and medial temporal lobe structures. Overall intelligence, as measured by standardized IQ tests, usually remains intact. Preservation of IQ occurs because memories formed before the onset of prolonged heavy drinking--the types of information and abilities tapped by intelligence tests--remain relatively well preserved compared with memories recently acquired. However, clinical and experimental evidence has shown that neurobehavioral dysfunction in alcoholic patients with KS does include nonmnemonic abilities, and further brain damage involves extensive frontal and limbic circuitries. Among the abnormalities are confabulation, disruption of elements of executive functioning and cognitive control, and emotional impairments. Here, we discuss the relationship between neurobehavioral impairments in KS and alcoholism-related brain damage. More specifically, we examine the role of damage to prefrontal brain systems in the neuropsychological profile of alcoholic KS.     

Pediatric traumatic brain injury: Language outcomes and their relationship to the arcuate fasciculus

Pediatric traumatic brain injury (TBI) may result in long-lasting language impairments alongside dysarthria, a motor-speech disorder. Whether this co-morbidity is due to the functional links between speech and language networks, or to widespread damage affecting both motor and language tracts, remains unknown.     

言语想象的神经机制

言语想象不仅在大脑预处理机制方面起到重要的作用,还是目前脑机接口领域研究的热点。与正常言语产生过程相比,言语想象的理论模型、激活脑区、神经传导路径等均与其有较多相似之处。而言语障碍群体的言语想象、想象有意义的词语和句子时的脑神经机制与正常言语产生存在差异。鉴于人类言语系统的复杂性,言语想象的神经机制研究还面临一系列挑战,未来研究可在言语想象质量评价工具及神经解码范式、脑控制回路、激活通路、言语障碍群体的言语想象机制、词语和句子想象的脑神经信号等方面进一步探索,为有效提高脑机接口的识别率提供依据,为言语障碍群体的沟通提供便利。     

Results of neurophysiologic studies in ophthalmic migraine

The influence in 8 of our patients with ophthalmic migraine of photic driving with sine-like flashing lights on EEG background activity was checked and the visually evoked potentials following the application of diffused simple light stimuli were analyzed using the recovery cycle technique. The results indicate a slightly increased tonic activity of the structures of the mesencephalic formatio reticularis, such as may be produced by slight functional disturbances. Some vegetative secondary symptoms of migraine attacks and some of the changes in EEG observed in patients with ophthalmic migraine are explicable by such an abnormality.     

The long‐term effects of institutional rearing,foster care intervention and disruptions in care on brain electrical activity in adolescence

Exposure to early psychosocial deprivation as a result of institutional care disrupts typical brain development. The Bucharest Early Intervention Project (BEIP) is the first longitudinal study to investigate the neurodevelopment of institutionalized infants randomized to a foster care (FCG) intervention versus care as usual (CAUG). Here, we present findings from a follow‐up assessment of brain electrical activity as indexed by resting EEG at age 16 years. In addition, we examined the effects of disruption of foster care placement (e.g. the number of moves among foster care placements) on brain electrical activity. Resting‐state EEG was collected from 48 CAUG, 46 FCG and 48 never institutionalized (NIG) control participants. Absolute (µV²) and relative (proportion) power were computed from eyes closed, resting EEG data for theta, alpha and beta frequency bands. The CAUG displayed higher relative theta and lower relative alpha power compared to the FCG at 16 years of age. The FCG showed brain activity comparable to the NIG. The results further showed that disruptions following the original foster care placement had an adverse effect on brain electrical activity. Within the foster care group, there were no effects of age of placement on EEG power. Placement of children who have experienced early institutional rearing into stable foster care settings ensure long‐term improvement in brain functioning.     

Physically Transcendent Awareness: A Comparison of the Phenomenology of Consciousness Before Birth and After Death

Veridical evidence of a physically transcendent source of consciousness comes from both extremes of the life span when central nervous system functioning is compromised, suggesting that some form of personhood can exist independently of known cellular processes associated with the body. In pre- and perinatal accounts, veridical memories have surfaced of events in the first two trimesters, long before the central nervous system is fully functional, continuing through the third trimester, when measurable brain activity begins, until just after birth. In the empirically verifiable out-of-body phase of near-death experience (NDE) accounts, a source of consciousness has been shown to record events when measurable metabolic processes, including brain activity, have ceased altogether. These two states have similar phenomenologies, suggesting that a physically transcendent source representing individual consciousness predates physical life at the moment of conception and survives it after death, and that its maturity and functioning do not directly reflect the level of central nervous system functioning in the body.     

Maternal sensitivity and infant response to frustration: The moderating role of EEG asymmetry

Two hundred and thirty-three 5-month-old infants and their mothers participated in a study designed to examine the influence of maternal sensitivity and infant neurophysiology, as well as interactions between these, on infants’ regulatory behavior and reactivity to emotional challenge. Maternal sensitivity was measured during two mother–child free-play episodes prior to the challenge task. Infant neurophysiology was derived from a measure of resting EEG asymmetry collected during a baseline episode. Infant regulatory behaviors (mother orienting and distraction) and reactivity to challenge (negative affect) were assessed during an arm restraint procedure. Maternal sensitivity predicted mother-orienting behavior for all infants, regardless of baseline EEG asymmetry. Maternal sensitivity also predicted more distraction behaviors for infants with left frontal EEG asymmetry at baseline. In contrast, maternal sensitivity predicted more negative affect for infants with right frontal EEG asymmetry at baseline. These findings lend support for the hypothesis that maternal sensitivity and infant neurophysiological functioning interact to predict regulatory behavior and reactivity and are discussed in terms of the significance for understanding infant regulatory development in the first year of life.     

旋律语调疗法及其对失语症的临床应用

失语症是当今人类面临的一个重要的健康问题。旋律语调疗法被认为是治疗失语症的有效手段之一。传统旋律语调疗法强调严格的程序和材料,改编版本则依据患者情况进行调整,二者均能提高失语症者的自发言语产生、言语复述以及命名等能力。研究还表明,旋律语调疗法不仅能提高失语症者相关脑区的激活水平,而且也能通过影响失语症者的相关神经结构改善其言语功能。未来研究需要进一步确定该疗法的干预机制及其对汉语失语症的适用性。     

Some markers of mirroring appear intact in schizophrenia: evidence from mu suppression

Although schizophrenia is associated with impairments in social cognition, the scope and neural correlates of these disturbances are largely unknown. In this study, we investigated whether schizophrenia patients show impaired functioning of the mirror neuron system (MNS), as indexed by electroencephalographic (EEG) mu (8–13 Hz) suppression, a hypothesized biomarker of MNS activity that is sensitive to the degree of social interaction depicted in visual stimuli. A total of 32 outpatients and 26 healthy controls completed an EEG paradigm that included six action observation or execution conditions that differed in their degrees of social interaction. Participants also completed a validated empathy questionnaire. Across both groups, we found a significant linear increase in mu suppression across the conditions involving greater levels of social engagement and interaction, but no significant group or interaction effects. Patients self-reported diminished empathic concern and perspective taking, which showed some moderate relations to mu suppression levels. Thus, the schizophrenia group showed generally intact modulation of MNS functioning at the electrophysiological level, despite self-reporting empathic disturbances. The disturbances commonly seen on self-report, performance, and neuroimaging measures of mentalizing in schizophrenia may largely reflect difficulties with higher-level inferential processes about others’ emotions, rather than a basic incapacity to share in these experiences.     

The relation between electroencephalogram asymmetry and attention biases to threat at baseline and under stress

Electroencephalogram (EEG) asymmetry in the alpha frequency band has been implicated in emotion processing and broad approach-withdrawal motivation systems. Questions remain regarding the cognitive mechanisms that may help elucidate the observed links between EEG asymmetry and patterns of socioemotional functioning. The current study observed frontal EEG asymmetry patterns at rest and under social threat among young adults (N = 45, M = 21.1 years). Asymmetries were, in turn, associated with performance on an emotion-face dot-probe attention bias task. Attention biases to threat have been implicated as potential causal mechanisms in anxiety and social withdrawal. Frontal EEG asymmetry at baseline did not predict attention bias patterns to angry or happy faces. However, increases in right frontal alpha asymmetry from baseline to the stressful speech condition were associated with vigilance to angry faces and avoidance of happy faces. The findings may reflect individual differences in the pattern of response (approach or withdrawal) with the introduction of a mild stressor. Comparison analyses with frontal beta asymmetry and parietal alpha asymmetry did not find similar patterns. Thus, the data may reflect the unique role of frontal regions, particularly the dorsolateral prefrontal cortex, in cognitive control and threat detection, coupled with ruminative processes associated with alpha activity.     

Putative EEG measures of social anxiety: Comparing frontal alpha asymmetry and delta–beta cross-frequency correlation

The goal of the present study was to examine whether frontal alpha asymmetry and delta–beta cross-frequency correlation during resting state, anticipation, and recovery are electroencephalographic (EEG) measures of social anxiety. For the first time, we jointly examined frontal alpha asymmetry and delta–beta correlation during resting state and during a social performance task in high (HSA) versus low (LSA) socially anxious females. Participants performed a social performance task in which they first watched and evaluated a video of a peer, and then prepared their own speech. They believed that their speech would be videotaped and evaluated by a peer. We found that HSA participants showed significant negative delta–beta correlation as compared to LSA participants during both anticipation of and recovery from the stressful social situation. This negative delta–beta correlation might reflect increased activity in subcortical brain regions and decreased activity in cortical brain regions. As we hypothesized, no group differences in delta–beta correlation were found during the resting state. This could indicate that a certain level of stress is needed to find EEG measures of social anxiety. As for frontal alpha asymmetry, we did not find any group differences. The present frontal alpha asymmetry results are discussed in relation to the evident inconsistencies in the frontal alpha asymmetry literature. Together, our results suggest that delta–beta correlation is a putative EEG measure of social anxiety.     

Frontal brain electrical activity (EEG) and heart rate in response to affective infant-directed (ID) speech in 9-month-old infants

Many studies have shown that infants prefer infant-directed (ID) speech to adult-directed (AD) speech. ID speech functions to aid language learning, obtain and/or maintain an infant's attention, and create emotional communication between the infant and caregiver. We examined psychophysiological responses to ID speech that varied in affective content (i.e., love/comfort, surprise, fear) in a group of typically developing 9-month-old infants. Regional EEG and heart rate were collected continuously during stimulus presentation. We found the pattern of overall frontal EEG power was linearly related to affective intensity of the ID speech, such that EEG power was greatest in response to fear, than surprise than love/comfort; this linear pattern was specific to the frontal region. We also noted that heart rate decelerated to ID speech independent of affective content. As well, infants who were reported by their mothers as temperamentally distressed tended to exhibit greater relative right frontal EEG activity during baseline and in response to affective ID speech, consistent with previous work with visual stimuli and extending it to the auditory modality. Findings are discussed in terms of how increases in frontal EEG power in response to different affective intensity may reflect the cognitive aspects of emotional processing across sensory domains in infancy.     

The impact of developmental speech and language impairments on the acquisition of literacy skills

Children with developmental speech/language impairments are at higher risk for reading disability than typical peers with no history of speech/language impairment. This article reviews the literacy outcomes of children with speech/language impairments, clarifying the differential risk for three groups of children: speech production impairments alone, oral language impairments alone, and speech production and oral language impairments. Children at greatest risk for reading and writing disabilities are children with language impairments alone and children with comorbid speech impairments and language impairments. For children with speech impairments alone, there is limited risk for literacy difficulties. However, even when reading skills are within the average range, children with speech impairments may have difficulties in spelling. Children with language impairments are likely to display reading deficits in word decoding and reading comprehension. It is not clear what role early literacy interventions play in the amelioration of reading difficulties in these populations.     

Psychogenic amnesia – A malady of the constricted self

Autobiographical–episodic memory is the conjunction of subjective time, autonoetic consciousness and the experiencing self. Understanding the neural correlates of autobiographical–episodic memory might therefore be essential for shedding light on the neurobiology underlying the experience of being an autonoetic self. In this contribution we illustrate the intimate relationship between autobiographical–episodic memory and self by reviewing the clinical and neuropsychological features and brain functional imaging correlates of psychogenic amnesia – a condition that is usually characterized by severely impaired retrograde memory functioning, in absence of structural brain damage as detected by standard imaging. We demonstrate that in this disorder the autobiographical–episodic memory deficits do not exist in isolation, but occur with impairments of the autonoetic self-consciousness, emotional processing, and theory of mind or executive functions. Furthermore functional and metabolic brain alterations involving regions that are agreed upon to exert crucial roles in memory processes were frequently found to accompany the psychogenic memory “loss”.     

Stress‐related exhaustion disorder – clinical manifestation of burnout? A review of assessment methods,sleep impairments,cognitive disturbances,and neuro‐biological and physiological changes in clinical burnout

The aim of this paper was to provide an overview of the literature on clinically significant burnout, focusing on its assessment, associations with sleep disturbances, cognitive impairments, as well as neurobiological and physiological correlates. Fifty‐nine English language articles and six book chapters were included. The results indicate that exhaustion disorder (ED), as described in the Swedish version of the International Classification of Diseases, seems to be the most valid clinical equivalent of burnout. The data supports the notion that sleep impairments are causative and maintaining factors for this condition. Patients with clinical burnout/ED suffer from cognitive impairments in the areas of memory and executive functioning. The studies on neuro‐biological mechanisms have reported functional uncoupling of networks relating the limbic system to the pre‐frontal cortex, and decreased volumes of structures within the basal ganglia. Although there is a growing body of literature on the physiological correlates of clinical burnout/ED, there is to date no biomarker for this condition. More studies on the role of sleep disturbances, cognitive impairments, and neurobiological and physiological correlates in clinical burnout/ED are warranted.