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Mindfulness meditation is linked to a broad range of psychological and physical health benefits, potentially mediated by changes in neural oscillations. This study explored changes in neural oscillations associated with both immediate and regular mindfulness meditation practice. Electroencephalographic (EEG) data were collected from 40 healthy young adults (M age  = 20.8, 24 females) during eyes-closed resting and mindfulness meditation states in two separate recording sessions, six weeks apart. Participants were novice meditators, and following the first recording session, were randomly assigned to either a daily mindfulness meditation practice or classical music listening as an active control, which they completed until the second recording session. Traditional bands of delta (1.0-3.5 Hz), theta (4.0-7.5 Hz), alpha (8.0-13.0 Hz), beta (13.5-30.0 Hz), and gamma (30.5-45.0 Hz) were used to explore changes in global EEG spectral amplitude. A significant increase in theta between sessions was observed in both groups and states. Alpha decreased significantly during meditation compared with rest, and a three-way interaction indicated a smaller reduction during meditation between sessions in the mindfulness group. There was a similar interaction in beta, which remained stable between sessions during both rest and meditation in the mindfulness group while varying in the classical music listening group. No significant effects were observed in global delta or gamma amplitudes. These findings suggest that changes in neural oscillations associated with breath-focused mindfulness meditation may be related to processes underlying attention and awareness. Further research is necessary to consolidate these findings, particularly in relation to the associated health benefits., Competing Interests: Declaration of competing interest None of the authors have any potential conflicts of interest or competing interests to disclose., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Neuroscience has identified that mindfulness meditation induces a state of relaxed alertness, characterised by changes in theta and alpha oscillations and reduced sympathetic arousal, although the underlying mechanisms remain unclear. This study aims to address this gap by examining changes in neural oscillations and arousal during mindfulness meditation using both traditional and data-driven methods. Fifty-two healthy young adults underwent electroencephalography (EEG) and skin conductance level (SCL) recordings during resting baseline and mindfulness meditation conditions, both conducted with eyes closed. The EEG data revealed a significant decrease in traditional alpha (8-13 Hz) amplitude during mindfulness meditation compared to rest. However, no significant differences were observed between conditions in traditional delta, theta, beta, or gamma amplitudes. Frequency Principal Components Analysis (fPCA) was employed as a data-driven approach, identifying six components consistent across conditions. A complex delta-theta-alpha component significantly increased during mindfulness meditation. In contrast, low alpha (~9.5 Hz) and low alpha-beta (~11 Hz) components decreased significantly during mindfulness meditation. No significant differences were observed between conditions in the delta, high alpha, and high alpha-beta components. Additionally, there were no significant differences in SCL between conditions, nor were there correlations between traditional alpha or fPCA components and SCL. These findings support the conceptualisation of mindfulness meditation as a state of relaxed alertness, characterised by changes in neural oscillations likely associated with attention and awareness. However, the observed changes do not appear to be driven by arousal., Competing Interests: Conflict of interest None of the authors have potential conflicts of interest to be disclosed., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Mind-wandering is characterised as the emergence of thought and emotions which shift attention away from a primary task. It is thought to consume up to 50 % of our waking lives and has several negative implications. Breath-counting is one task that has been utilised in conjunction with electroencephalography (EEG) to examine the brain states associated with mind-wandering. Research has consistently found reductions in alpha oscillations during periods of mind-wandering relative to breath-focus. It is possible that such fluctuations reflect an arousal mechanism warranting further investigation. Thirty-seven participants completed a 15 min breath-counting task, with simultaneous recording of EEG and skin conductance level (SCL). During this task participants were required to self-identify periods of mind-wandering via button-press. Event-related spectral perturbation (ERSP) analysis was used to quantify changes in global alpha power (8-13 Hz) relative to the button press. The -8 to -4 s period prior to button-press was assessed as mind-wandering, and the 4 to 8 s period following the button-press as breath-focus. Relative to breath-focus, mind-wandering was associated with a significant decrease in global alpha power and significant increase in SCL, consistent with perceptual decoupling theory. However, changes in global alpha power and SCL did not correlate. These results suggest arousal is not the primary mechanism underlying alpha changes observed during breath-counting, thus additional processes should be considered., Competing Interests: Declaration of competing interest None of the authors have potential conflicts of interest to be disclosed., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Labor and delivery can entail complications and severe maternal morbidities that threaten a woman's life or cause her to believe that her life is in danger. Women with these experiences are at risk for developing posttraumatic stress disorder. Postpartum posttraumatic stress disorder, or childbirth-related posttraumatic stress disorder, can become an enduring and debilitating condition. At present, validated tools for a rapid and efficient screen for childbirth-related posttraumatic stress disorder are lacking., Objective: We examined the diagnostic validity of the Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, for detecting posttraumatic stress disorder among women who have had a traumatic childbirth. This Checklist assesses the 20 Diagnostic and Statistical Manual of Mental Disorders, posttraumatic stress disorder symptoms and is a commonly used patient-administrated screening instrument. Its diagnostic accuracy for detecting childbirth-related posttraumatic stress disorder is unknown., Study Design: The sample included 59 patients who reported a traumatic childbirth experience determined in accordance with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, posttraumatic stress disorder criterion A for exposure involving a threat or potential threat to the life of the mother or infant, experienced or perceived, or physical injury. The majority (66%) of the participants were less than 1 year postpartum (for full sample: median, 4.67 months; mean, 1.5 years) and were recruited via the Mass General Brigham's online platform, during the postpartum unit hospitalization or after discharge. Patients were instructed to complete the Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, concerning posttraumatic stress disorder symptoms related to childbirth. Other comorbid conditions (ie, depression and anxiety) were also assessed. They also underwent a clinician interview for posttraumatic stress disorder using the gold-standard Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. A second administration of the Checklist was performed in a subgroup (n=43), altogether allowing an assessment of internal consistency, test-retest reliability, and convergent and diagnostic validity of the Checklist. The diagnostic accuracy of the Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, in reference to the Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, was determined using the area under the receiver operating characteristic curve; an optimal cutoff score was identified using the Youden's J index., Results: One-third of the sample (35.59%) met the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria for a posttraumatic stress disorder diagnosis stemming from childbirth. The Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, symptom severity score was strongly correlated with the Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, total score (ρ=0.82; P<.001). The area under the receiver operating characteristic curve was 0.93 (95% confidence interval, 0.87-0.99), indicating excellent diagnostic performance of the Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. A cutoff value of 28 optimized the sensitivity (0.81) and specificity (0.90) and correctly diagnosed 86% of women. A higher value (32) identified individuals with more severe posttraumatic stress disorder symptoms (specificity, 0.95), but with lower sensitivity (0.62). Checklist scores were also stable over time (intraclass correlation coefficient, 0.73), indicating good test-retest reliability. Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, scores were moderately correlated with the depression and anxiety symptom scores (Edinburgh Postnatal Depression Scale: ρ=0.58; P<.001 and the Brief Symptom Inventory, anxiety subscale: ρ=0.51; P<.001)., Conclusion: This study demonstrates the validity of the Posttraumatic Stress Disorder Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, as a screening tool for posttraumatic stress disorder among women who had a traumatic childbirth experience. The instrument may facilitate screening for childbirth-related posttraumatic stress disorder on a large scale and help identify women who might benefit from further diagnostics and services. Replication of the findings in larger, postpartum samples is needed., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Sokolov described both phasic and tonic aspects of the Orienting Reflex (OR), but subsequent research and theory development has focussed primarily on the phasic OR at the expense of the tonic OR. The present study used prestimulus skin conductance level (SCL) during a dishabituation paradigm to model the tonic OR, examining its amplitude patterning over repeated standard stimulus presentations and a change stimulus. We expected sensitisation (increased amplitude) following the initial and change trials, and habituation (decrement) over the intervening trials. Prestimulus EEG alpha level was explored as a potential central measure of the tonic OR (as an inverse correlate), examining its pattern over stimulus repetition and change in relation to the SCL model. We presented a habituation series of innocuous auditory stimuli to two groups (each N = 20) at different ISIs (Long 13-15 s and Short 5-7 s) and recorded electrodermal and EEG data during two counterbalanced conditions; Indifferent: no task requirements; Significant: silent counting. Across groups and conditions, prestimulus SCLs and alpha amplitudes generally showed the expected trials patterns, confirming our main hypotheses. Findings have important implications for including the assessment of Sokolov's tonic OR in modelling central and autonomic nervous system interactions of fundamental attention and learning processes., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: Endometriosis is associated with neuroplastic changes in cognitive control and pain processing networks. This was the first study to assess eyes-closed resting electroencephalogram (EEG) oscillatory amplitudes in women with endometriosis compared to healthy controls, and explore the relationship with chronic pelvic pain., Methods: Women with endometriosis-related chronic pelvic pain and individually age-matched pain-free controls (N = 20 per group) documented pelvic pain for 28 days before having continuous EEG recorded during a 2 min eyes closed resting state. Natural frequency components were extracted for each group using frequency principal components analysis. Corresponding components were assessed for group differences and correlated with pain scores., Results: Relative to controls, the endometriosis group had greater component amplitudes in delta (0.5 Hz) and beta (∼28 Hz), and reduced alpha (∼10 Hz). Delta and beta amplitudes were positively associated with pain severity, but only beta maintained this association after delta-beta amplitude coupling was controlled., Conclusions: Enhanced resting delta and beta amplitudes were seen in women with endometriosis experiencing chronic pelvic pain. This delta-beta coupling varied with pelvic pain severity, perhaps reflecting altered cholinergic tone and/or stress reactivity., Significance: Endometriosis-related changes in central pain processing demonstrate a distinct neuronal oscillatory signature detectable at rest., (Copyright © 2023 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

The NoGo P3 event-related potential (ERP) component is often related to response inhibition, although its function in equiprobable Go/NoGo tasks is debated. Previous findings concerning the auditory equiprobable NoGo P3 (or P3a) could be distorted by averaging latency-variable ERP components. This study aimed to control NoGo P3 latency jitter to investigate the component's relationship with inhibitory demands and its neuronal sources across trials. P3 latency jitter was controlled using a novel procedure to enable single-trial P3 quantification across 126 healthy young adults (M age  = 20.3, SD = 2.8 years) using principal components analysis. NoGo inhibitory demands and performance were measured using the Lateralised Readiness Potential and error rates, respectively. The stimulus-locked P3 (SL-P3) was also analysed to assess the 'blurring effect' (i.e., smearing) associated with averaging latency-variable ERP trial data. A Spearman's rank correlation across 4700 NoGo trials demonstrated that the relationship between latency-adjusted P3 (LA-P3) and inhibitory demands was inconsequential. The cortical sources associated with LA-P3, using eLORETA, were in the premotor and prefrontal cortices, cingulate, and precuneus. SL-P3 was smaller than LA-P3, and that difference was positively related to P3 latency jitter; its source solution was also limited to lower activation in the prefrontal cortex. SL-P3 was not related to inhibitory demands or performance. This study indicates that NoGo P3 should not index response inhibition in auditory equiprobable tasks. Instead, the findings support a neuroinhibition account relating NoGo P3 to attention. Blurring effects were also shown to impact a standard ERP measure and its source solution, encouraging ERP latency-adjustment in future research., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Our previous studies of the equiprobable auditory Go/NoGo task have been used to substantiate a perceptual/cognitive Processing Schema in young and older adults, and in children. The processes in the Schema are linked to PCA components derived separately from Go and NoGo ERPs. Here we investigated sex differences in the child Schema. Two groups of fourteen children (aged 8 to 13 years) were individually matched on age and presented with four stimulus blocks of the equiprobable Go/NoGo task, each containing 75 NoGo and 75 Go tones in random order. Separate NoGo and Go ERPs were obtained from each child and submitted to temporal Principal Components Analyses (PCAs). Each ERP was analysed in two epochs (-100-400 ms and 300-800 ms) to improve the cases:variables ratio. Four pairs of temporal PCAs, each with unrestricted VARIMAX rotation, separately quantified the NoGo and Go ERPs of each epoch in each group. After these pairs were combined in temporal order, four sets of similar components were extracted. Many identified components were differentially enhanced to either NoGo or Go, as in previous work with children. The Female group had NoGo component latencies that were systematically some 3.5% greater than in Males, but there were no sex differences in Go latencies. Females also displayed fewer NoGo commission and Go omission errors, and faster Go RT than Males. Females had larger NoGo N2b, and larger Go components from N2b through to the late positivity. These results, including their ERP component/behaviour correlations, can be integrated as a task-specific behavioural and ERP processing enhancement in girls that suggests their developmental advantage over boys in this age range., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Auditory stimulus intensity of innocuous tones is generally thought to have a direct effect on the amplitude of ERP components, but these effects have rarely been explored across a wide component range, or in multiple paradigms. Here we investigate component sensitivity to stimulus intensity differences in two studies. Study 1 (N = 36) employed a between-participants paradigm in which repeated trains of standard stimuli were presented as 50 or 80 dB SPL 1000 Hz tones. Study 2 (N = 18) used a within-participant presentation of alternating 60 and 80 dB SPL 1000 Hz tones. Electrode caps with 19 channels (referred to linked ears) generated ERPs covering the first 600 ms of each participant's EEG responses; these were submitted to separate temporal PCAs in each study. A similar series of components was obtained in each study: P1, N1a, N1b, N1c, P2, P3a, P3b, nP3, SW1, and SW2; an N2 was found in Study 2 only. Loud tones in Study 1 produced greater amplitudes in all components except SW1. In Study 2, Loud cf. Soft tones produced smaller P1 and nP3, larger N1 components, P2, and P3a, with no effect on N2, P3b, SW1 or SW2. These results indicate similar sequential processes underlying sensory processing in one- and two-stimulus paradigms, with the later stimulus intensity effects varying with paradigm., (Copyright © 2022 Elsevier B.V. All rights reserved.)

This study investigated age-related changes in the EEG of subtypes of Attention-Deficit/Hyperactivity Disorder (AD/HD) compared with neurotypical controls, using an eyes-open resting condition. Two hundred and twenty five children between the ages of 5 and 16 years participated in this study. Groups consisted of AD/HD of the combined (AD/HDcom) and inattentive (AD/HDin) types, which were compared with controls for each of three age ranges: Young (5-8 years), Middle (9-12 years), and Old (13-16 years). The EEG was recorded and analyzed using AMLAB hardware and software, and Fourier transformed to provide estimates for total power, and absolute and relative power in the delta, theta, alpha and beta bands. Compared to controls, the AD/HD groups had globally increased relative theta. Regional differences were found for absolute and relative alpha and beta. Compared to AD/HDcom, AD/HDin had globally reduced total power, absolute and relative theta, and absolute alpha. Regional differences only were found for absolute and relative delta, absolute beta, and relative alpha. No simple interactions were found for diagnostic factors with age. These results indicate that maturational effects can be observed between subtypes of AD/HD and controls in the eyes-open condition with similarities to those reported in eyes-closed conditions, although substantial differences are apparent in the maturation of fast wave activity, primarily alpha. These results provide evidence of maturational differences between subtypes of AD/HD in eyes-open conditions, and provide additional support for the suggestion that subtypes of AD/HD differ in severity rather than the nature of underlying neurological impairment., (Copyright © 2022 Elsevier B.V. All rights reserved.)

This study investigated age related changes in the EEG of normal children in an eyes-open condition, in order to provide developmental norms for the study of children and adolescents with Attention-Deficit/Hyperactivity Disorder (AD/HD) - see our companion paper (Mason et al., submitted). EEG was recorded at 17 sites from 75 children (63 boys and 12 girls, in the approximately 5:1 ratio common in AD/HD) between the ages of 5 and 16 years. They comprised three groups, each of 25 children (21 boys and 4 girls), divided into Young (5-8 years), Middle (9-12 years), and Old (13-16 years). The EEG was recorded during an eyes-open resting condition and Fourier transformed to provide estimates for total power, and absolute and relative power in the delta, theta, alpha and beta bands. Total power and absolute delta, theta, alpha, and beta decreased with increasing age, as did relative delta, while relative alpha increased with increasing age. Changes occurred faster in the posterior regions for total power, absolute theta and alpha, relative theta, and in frontal regions for absolute and relative beta. Some lateral developmental effects differed with band. These results indicate that maturation effects observed in the eyes-open EEG show some similarities to those reported in eyes-closed conditions, although substantial differences are apparent in the maturation of fast wave activity, particularly alpha. The data provide simple age-norms for eyes-open investigations of EEG differences in young clinical groups, particularly AD/HD. They encourage further investigations of the activational effects of this simple eyes-closed/eyes-open manipulation, which may aid understanding of the energetics of behaviour., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Since the equiprobable Go/NoGo task lacks the dominant Go imperative of the usual Go/NoGo (with more Go than NoGo stimuli), it is generally regarded as involving little inhibition. However, children have relative difficulty with this task, and have a large frontal NoGo N2. We previously found that this 'child N2' does play an inhibitory role, with larger frontal N2b associated with fewer commission errors. Here we investigated age-related developmental differences in the N2b and other components in the equiprobable Go/NoGo task. Two groups of eighteen Younger children (aged 8.0 to 10.3 years) and eighteen Older children (aged 10.4 to 12.8 years), matched on sex, were presented with three stimulus blocks each containing 100 Go and 100 NoGo tone stimuli in random order. Four temporal PCAs, each with unrestricted VARIMAX rotation, separately quantified the Go and NoGo ERPs of each group, and similar components were extracted from each set. Most identified components were differentially enhanced to either Go or NoGo, as in adults, supporting a previously-proposed differential sequential processing schema. The Older group had Go component latencies that were systematically reduced by some 7.4% from the Younger group, and they displayed faster RT and fewer omission and commission errors. Between subjects in the Older group, larger frontocentral NoGo N2b was associated with fewer commission errors. Hence the NoGo N2b in this paradigm can be interpreted as an individual marker of inhibition in older, but not young, children., (Copyright © 2021. Published by Elsevier B.V.)

Amyotrophic lateral sclerosis (ALS) is a deadly neurodegenerative disorder affecting motor neurons in the spinal cord and brain. Studies have reported on atrophy within segments of the cervical cord, but we are not aware of previous investigations of the whole spinal cord. Herein we present our findings from a 3T MRI study involving 32 subjects (15 ALS participants and 17 healthy controls) characterizing cross-sectional area along the entire cord. We report atrophy of the cervical enlargement in ALS participants, but no evidence of atrophy of the thoracolumbar enlargement. These results suggest that MR-based analyses of the cervical cord may be sufficient for in vivo investigations of spinal cord atrophy in ALS, and that atrophy of the cervical enlargement (C4-C7) is a potential imaging marker for quantifying lower motor neuron degradation., Competing Interests: Declaration of Competing Interest In the past two years, J.M.H. has consulted for Amathus Therapeutics, Rodin Therapeutics, Abata Therapeutics, FogPharma, Sanofi-Aventis, Longitude Capital, and the Alzheimer’s Drug Discovery Foundation. J.M.H. is a paid Editor-in-Chief for ACS Chemical Neuroscience. J.M.H. is a co-founder and equity holder in Eikonizo Therapeutics (a license holder to J.M.H. patents) and in Sensorium Therapeutics. J.M.H. is a scientific advisory board member and equity holder in Psy Therapeutics, Delix Therapeutics, and Fuzionaire Diagnostics. J.M.H. has received sponsored research grants from Atai Life Sciences and Expesicor and has received honoraria for speaking or advisory service at non-profit academic institutions. N.A. is currently employed by Sanofi Genzyme. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Resting EEG, measured in eyes-closed (EC) and eyes-open (EO) states, can provide insight into behavioural differences between groups. Surprisingly, differences in resting EEG between females and males have not been investigated systematically in previous literature. The present study utilised the four traditional EEG bands to confirm their baseline EC topographies and reactivity (EO minus EC) across groups, to clarify topographical differences between sexes, and to confirm alpha as a measure of arousal. Participants were eighty healthy young adults (40 female), with a mean age of 20.4 (range 18-26) years. Continuous resting EEG was recorded from 30 scalp sites during three 2-minute conditions (EO1, EC, EO2), and EOG-corrected. Data from each condition were divided into 60 sequential 2-second epochs. Accepted artefact-free epochs were Fourier Transformed, and absolute amplitudes in the delta (0.5-3.5 Hz), theta (4.0-7.5 Hz), alpha (8.0-13.0 Hz), and beta (13.5-29.5 Hz) bands were calculated. Across groups in EC, significant topographical differences were found between the band amplitudes, broadly compatible with previous reports. Females had greater overall amplitudes in delta, alpha and beta, enhanced midline activity in theta, and parietal and midline activity in the alpha and beta bands. From EC to EO, reactivity was apparent across the bands as significant reductions, particularly in the parietal region. For females compared to males, the reduction in parietal midline delta and theta, parietal alpha and parietal midline beta was significantly larger. Additionally, across groups, alpha activity was confirmed as an inverse measure of arousal. These findings indicate significant differences in neuronal activity between young adult females and males, and help our interpretation of alpha changes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the central nervous system that results in a progressive loss of motor function and ultimately death. It is critical, yet also challenging, to develop non-invasive biomarkers to identify, localize, measure and/or track biological mechanisms implicated in ALS. Such biomarkers may also provide clues to identify potential molecular targets for future therapeutic trials. Herein we report on a pilot study involving twelve participants with ALS and nine age-matched healthy controls who underwent high-resolution resting state functional magnetic resonance imaging at an ultra-high field of 7 Tesla. A group-level whole-brain analysis revealed a disruption in long-range functional connectivity between the superior sensorimotor cortex (in the precentral gyrus) and bilateral cerebellar lobule VI. Post hoc analyses using atlas-derived left and right cerebellar lobule VI revealed decreased functional connectivity in ALS participants that predominantly mapped to bilateral postcentral and precentral gyri. Cerebellar lobule VI is a transition zone between anterior motor networks and posterior non-motor networks in the cerebellum, and is associated with a wide range of key functions including complex motor and cognitive processing tasks. Our observation of the involvement of cerebellar lobule VI adds to the growing number of studies implicating the cerebellum in ALS. Future avenues of scientific investigation should consider how high-resolution imaging at 7T may be leveraged to visualize differences in functional connectivity disturbances in various genotypes and phenotypes of ALS along the ALS-frontotemporal dementia spectrum., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

The immediately-prestimulus electroencephalographic (EEG) brain state influences subsequent event-related processing, dynamically impacting event-related potential (ERP) and behavioural outcomes. Both EEG and ERPs are known to undergo age-related change, yet few have investigated the consistency in their dynamic interrelations in the context of ageing. The present investigation assessed the impact of prestimulus alpha and beta brain states in 20 young (18-26 years) and 20 gender-matched healthy older (59-75 years) adults who completed an equiprobable auditory Go/NoGo paradigm. Prestimulus alpha and beta band amplitudes in their prominent band topographies were separately used to derive Go and NoGo ERPs at 10 ascending levels of prestimulus activity, and ERP components were derived for these levels using Principal Components Analysis. Prestimulus alpha directly modulated Go/NoGo P3a amplitudes across the groups, while beta inversely modulated the young (cf. older) adult NoGo N1-1, each supporting and extending limited prior research. Several novel effects were also uncovered, most notably an inverse relationship between prestimulus alpha and reaction time. Prestimulus alpha and beta were confirmed as significant determinants of the processing outcomes in this task, and the complex pattern of results provides a normative map in healthy ageing., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This article reviews the eyes-open and eyes-closed resting electroencephalogram (EEG) literature for Attention-Deficit/Hyperactivity Disorder (AD/HD) from 2002 to 2019. This time has seen substantial increase in interest in resting state EEG, with investigations moving from a comparison of an AD/HD sample to a control group, to research investigating a wide range of theoretical and clinical aspects of the disorder. This has included investigations of subgroups based on their EEG profile, sex differences in the EEG, increasing interest in the EEG of adults, and the effects of comorbid disorders on the EEG of people with AD/HD. Research has further investigated the hyper- and hypo- arousal models of AD/HD, as well as the developmental deviation model. From a clinical perspective, a growing body of literature is emerging trying to ascertain if the EEG can be used as a diagnostic test, particularly the theta/beta ratio. While these advances have been made, there is widespread use of both the eyes-open and eyes-closed resting paradigms as being interchangeable, despite the two paradigms differ on a number of important factors. There is also lack of independent replication within the literature, which is needed to consolidate many of the findings that have been published., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Some 40 years ago, Erol Başar began an interesting line of brain dynamics research on the phase of oscillatory EEG activity. Stimuli presented at a fixed interstimulus interval (ISI) were reported to produce a "preferred phase angle" at stimulus onset in the ongoing EEG oscillations, so that cortical negativity occurred more often than expected. Our previous work has confirmed this phenomenon in young adults, and linked it to enhancements in stimulus-elicited ERP components and behaviour. The present study sought evidence for this phenomenon in older adults. Twenty healthy independent-living participants (5 males) aged 59.8 to 74.8 years (M = 68.2) completed a fixed ISI equiprobable auditory oddball task. EEG phases in four traditional bands were computed separately for each artefact-free Go and NoGo trial. These were used to group accepted trials according to the phase quartile at stimulus onset in each band, forming 16 mean ERPs for each participant at each phase quartile/band combination, separately for Go and NoGo. The 32 mean ERPs were decomposed by separate Principal Component Analyses, and the N1 and P3 components were examined as a function of EEG phase at stimulus onset in each band. Differential preferential occurrence of phase states was found in all bands, generally confirming prior results in young adults despite important age differences in both EEG spectra and ERP morphology. Substantial effects on N1 and P3 components, as well as prestimulus CNVs, are discussed. The stability of this phenomenon across age indicates its important role in perception and cognition., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Data from three published studies examining autonomic and ERP measures in variants of a dishabituation paradigm were re-analysed to clarify ambiguous novelty results. The three studies manipulated 1. Novelty, 2. Novelty and Intensity, and 3. Novelty and Significance, in auditory dishabituation paradigms at very long interstimulus intervals (ISIs). The question of whether any single ERP matches SCR as the benchmark for the phasic Orienting Reflex (OR) was also addressed. Finally, we aimed to align the re-analysed measures of this and the previous analyses with processes of Preliminary Process Theory (PPT). The SCR demonstrated decrement, recovery, and dishabituation. A summary temporal PCA extracted PN (Processing Negativity), P3a, P3b, Novelty P3, and classic SW for detailed analysis. P3b and SW showed decrement but no recovery at the change trial, while Respiratory pause (RP) and Novelty P3 demonstrated decrement and recovery, but no dishabituation. Post hoc exploration of observed power versus sample size for each of these findings confirmed their robustness. No decrement for PN was also confirmed. Five autonomic and ERP groupings emerged and aligned with modules of processing in PPT: ECR1 (cardiac deceleration), P1, N1-3, and PN - stimulus registration; RP and Novelty P3 - Novelty registration; Peripheral Vasoconstriction (PVC) and P3b - Intensity registration; and ECR2 (cardiac acceleration) and classic SW - Response system. The SCR was confirmed as the sole index of the phasic OR. The pattern of results for the Late Positive Complex (LPC) components (P3a, P3b, Novelty P3, and SW) suggests each is differentially sensitivity to selective determinants of the phasic OR, and consequently the summary LPC is presented as the most appropriate central index of the phasic OR., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In 1999, the International Federation of Clinical Neurophysiology (IFCN) published "IFCN Guidelines for topographic and frequency analysis of EEGs and EPs" (Nuwer et al., 1999). Here a Workgroup of IFCN experts presents unanimous recommendations on the following procedures relevant for the topographic and frequency analysis of resting state EEGs (rsEEGs) in clinical research defined as neurophysiological experimental studies carried out in neurological and psychiatric patients: (1) recording of rsEEGs (environmental conditions and instructions to participants; montage of the EEG electrodes; recording settings); (2) digital storage of rsEEG and control data; (3) computerized visualization of rsEEGs and control data (identification of artifacts and neuropathological rsEEG waveforms); (4) extraction of "synchronization" features based on frequency analysis (band-pass filtering and computation of rsEEG amplitude/power density spectrum); (5) extraction of "connectivity" features based on frequency analysis (linear and nonlinear measures); (6) extraction of "topographic" features (topographic mapping; cortical source mapping; estimation of scalp current density and dura surface potential; cortical connectivity mapping), and (7) statistical analysis and neurophysiological interpretation of those rsEEG features. As core outcomes, the IFCN Workgroup endorsed the use of the most promising "synchronization" and "connectivity" features for clinical research, carefully considering the limitations discussed in this paper. The Workgroup also encourages more experimental (i.e. simulation studies) and clinical research within international initiatives (i.e., shared software platforms and databases) facing the open controversies about electrode montages and linear vs. nonlinear and electrode vs. source levels of those analyses., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: Global EEG alpha activity is negatively correlated with skin conductance level (SCL), supporting alpha as an inverse marker of arousal. Frequency Principal Components Analysis (f-PCA) of resting EEG amplitude spectra has demonstrated natural components in the alpha band of healthy persons. This is a preliminary exploration of whether such components differ with arousal, possibly underpinning the anomalous ADHD hypoarousal link to reduced alpha., Method: Twenty-seven right-handed undergraduate students participated in three 2 minute blocks of resting eyes-open/closed EEG and SCL: EO1, EC, EO2. For each condition, mean EEG spectra were submitted to separate f-PCAs., Results: The inverse alpha/SCL relationship was confirmed for band amplitudes. EO had two alpha components; both correlated negatively with SCL. EC alpha contained four components, but only one had a substantial negative correlation with SCL; two had no relationship, suggesting natural alpha components with different non-arousal functionality in EC., Conclusion: Some alpha components in both EC and EO reflect arousal, with other non-arousal components in EC. Our f-PCA approach offers insight into previously-noted alpha anomalies in disorders such as ADHD., Significance: This proof of concept demonstration in typical participants may provide the basis for a new research effort in clinical disorders involving atypical arousal patterns., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Listening to white noise may facilitate cognitive performance, including new word learning, for some individuals. This study investigated whether auditory white noise facilitates the learning of novel written words from context in healthy young adults. Sixty-nine participants were required to determine the meaning of novel words placed within sentence contexts during a silent reading task. Learning was performed either with or without white noise, and recognition of novel word meanings was tested immediately after learning and after a short delay. Immediate recognition accuracy for learned novel word meanings was higher in the noise group relative to the no noise group, however this effect was no longer evident at the delayed recognition test. These findings suggest that white noise has the capacity to facilitate meaning acquisition from context, however further research is needed to clarify its capacity to improve longer-term retention of meaning., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Brain dynamics research has highlighted the contributions of the ongoing EEG to ERP and behavioural responses. This study examined the effects of state-related EEG changes, from rest to the task and within the task, on stimulus-response efforts in a visual Continuous Performance Test (CPT). EEG was recorded from fifty-six adults at rest with eyes-closed (EC) then eyes-open (EO), and during the CPT. Principal Components Analyses decomposed the EEG obtained from EC, EO and the task-based periods immediately pre-cue (PC) and pre-imperative (PI), and the ERPs to the cued Go/NoGo imperatives. EC amplitudes were correlated with Go/NoGo ERP amplitudes and behavioural outcomes. EEG amplitude changes from EO to PC, and from PC to PI, were assessed as predictors of these response measures. Longer mean reaction time (RT) was associated with greater RT variability (RTV) and reduced Go P2. The two EC alpha components correlated positively with RTV, and NoGo P1 and P2 positivity. Delta/theta amplitude reductions from PC to PI predicted Go N1-1 and NoGo N2b enhancements. Alpha-1 decreases from PC to PI predicted larger P2 and poorer NoGo accuracy rates, while alpha-3 decrements positively predicted NoGo P1. These findings highlight the ongoing alpha arousal effects on stimulus-response efforts, and the low frequency shifts in the cue to imperative interval associated with stimulus anticipation and response preparation. These relationships offer novel insights into the effects of pretask EEG activity, and within-task EEG changes, on attention and cognitive control processes., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)

Objective: Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common psychiatric disorders found in children. While an extensive literature has documented the EEG in this clinical population, few studies have investigated EEG throughout the lifespan in ADHD. This study aimed to investigate EEG maturational changes, in subjects with ADHD combined type, that spanned from childhood into adulthood., Method: Twenty five male adults with ADHD were assessed between the ages of 8-12 years and again as adults. At both ages, an EEG was recorded during an eyes-closed resting period, and power estimates were calculated for relative delta, theta, alpha and beta., Results: At the childhood assessment, the ADHD subjects had elevated posterior delta. Relative theta was elevated, with diminished alpha activity across all sites. Significant maturational changes were observed, with reductions in the delta and theta bands, and increases in the alpha and beta bands across all electrodes. In adulthood, relative to controls, diminished frontal delta and elevated global theta activity were apparent., Conclusions: Substantial developmental changes occurred in the EEG of these subjects. These results identify important issues when using EEG as part of the diagnosis for ADHD., Significance: This study is the first to explore EEG changes from childhood to adulthood over an 11 year period in the same subjects with ADHD., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Response variability has been identified as a useful predictor of executive function and performance in non-clinical samples in the Go/NoGo task. The present study explores the utility of reaction time variability (RTV) and EEG measures as predictors of Go/NoGo performance outcomes and ERP component amplitudes. Forty-four young adults had EEG recorded across eyes-closed (EC) and eyes-open (EO) resting states, and during an auditory Go/NoGo task. The 18 individuals with the lowest/highest RTV were assessed for differences in behavioural outcomes. As expected, individuals with high RTV committed more Go/NoGo errors and had smaller Go P3b and NoGo P3a amplitudes, and greater Go Slow Wave positivity, reflecting inefficient decision-making and response control efforts underlying performance. When RTV and EEG measures were modelled as predictors of Go/NoGo responses, RTV and task-related changes in delta were identified as positive predictors of Go SW amplitude; while RTV and prestimulus delta amplitudes negatively predicted NoGo accuracy rates. Prestimulus delta was also found to solely predict Go mean RT and NoGo SW negativity; effects that were independent of RTV. As delta has been implicated in attention-related mechanisms, these findings suggest that inadequate attention and task engagement underpin the variability in Go/NoGo performance., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Ongoing EEG activity contributes to ERP outcomes of stimulus processing, and each of these measures is known to undergo (sometimes significant) age-related change. Variation in their relationship across the life-span may thus elucidate mechanisms of normal and pathological ageing. This study assessed the relationships between low-frequency EEG prestimulus brain states, the ERP, and behavioural outcomes in a simple equiprobable auditory Go/NoGo paradigm, comparing these for 20 young (M age  = 20.4 years) and 20 healthy older (M age  = 68.2 years) adults. Prestimulus delta and theta amplitudes were separately assessed; these were each dominant across the midline region, and reduced in the older adults. For each band, (within-subjects) trials were sorted into ten increasing prestimulus EEG levels for which separate ERPs were derived. The set of ten ERPs for each band-sort was then quantified by PCA, independently for each group (young, older adults). Four components were primarily assessed (P1, N1-1, P2/N2b complex, and P3), with each showing age-related change. Mean RT was comparable, but intra-individual RT variability increased in older adults. Prestimulus delta and theta each generally modulated component positivity, indicating broad influence on task processing. Prestimulus delta was primarily associated with the early sensory processes, and theta more with the later stimulus-specific processes; prestimulus theta also inversely modulated intra-individual RT variability across the groups. These prestimulus EEG-ERP dynamics were consistent between the young and older adults in each band for all components except the P2/N2b, suggesting that across the lifespan, Go/NoGo categorisation is differentially affected by prestimulus delta and theta., (Copyright © 2018 Elsevier B.V. All rights reserved.)

It has been proposed that white noise can improve cognitive performance for some individuals, particularly those with lower attention, and that this effect may be mediated by dopaminergic circuitry. Given existing evidence that semantic priming is modulated by dopamine, this study investigated whether white noise can facilitate semantic priming. Seventy-eight adults completed an auditory semantic priming task with and without white noise, at either a short or long inter-stimulus interval (ISI). Measures of both direct and indirect semantic priming were examined. Analysis of the results revealed significant direct and indirect priming effects at each ISI in noise and silence, however noise significantly reduced the magnitude of indirect priming. Analyses of subgroups with higher versus lower attention revealed a reduction to indirect priming in noise relative to silence for participants with lower executive and orienting attention. These findings suggest that white noise focuses automatic spreading activation, which may be driven by modulation of dopaminergic circuitry., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Substantial research into the brain dynamics underlying cognitive functioning during tasks links the brain's EEG activity to the stimulus-evoked ERP activity. This study focused on examining how the resting state intrinsic EEG, and the change from rest to the task, affect these stimulus-response processes. Forty young adults (aged 20.3 ± 2.3 years) had EEG recorded during eyes-closed (EC) and eyes-open (EO) resting states, and then during an auditory Go/NoGo task. Amplitude in the delta to beta bands was analyzed for the overall resting state EEG, the reactive change from EC to EO, and for the change from EO to the task (termed task-related change here). The relationships between these EEG measures and Go/NoGo behavioral outcomes and ERPs were assessed. Greater resting state delta and theta amplitudes were linked to Go N1-1 enhancements, but only resting state delta correlated with the NoGo N1-1. These relationships replicate previous data and highlight the functional relevance of low frequency intrinsic activity in attentional processes. However, delta increases from EO to the task predicted poorer Go response accuracy and variability, and enhanced Go Slow Wave (SW) positivity. This increase in delta, and smaller alpha-1 increments, were associated with longer mean RTs. Theta increases predicted larger Go N1-1 amplitudes, but lower NoGo accuracy rates, while beta-1 increments were predictive of NoGo SW negativity. These novel effects suggest that task-related EEG changes impact decision-making and cognitive control processes, and subsequent behavioral performance., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A sequential processing model for adults in the auditory equiprobable Go/NoGo task has been developed in recent years. This used temporal principal components analysis (PCA) to decompose Go/NoGo event related potential (ERP) data into components that mark stages of perceptual and cognitive processing. The model has been found useful in frameworking several studies in young and older adults, and in children. Recently, it has been demonstrated that the common PCA approach of decomposing Go and NoGo ERP data together results in misallocation of variance between the conditions, distorting the timing, topography, and amplitudes of the resultant components in each condition. The present study thus reanalyses data from a child study, conducting separate PCAs on the data from each condition. Multiple regression was then used to seek links with behavioural measures from the task. In addition to confirming the previous NoGo N2b/inhibitory processing link, novel NoGo Negative Slow Wave/error evaluation and Go N1-1/RT variability links were obtained. Based on these outcomes, the recommended separate application of PCAs to Go and NoGo data was confirmed. The present data were used to develop a child-specific sequential processing schema for this paradigm, suggesting earlier separation of the Go and NoGo processing chains, and the need to include an additional inhibition and evaluation stage. The child schema should be useful in future studies involving this and other two-choice reaction tasks., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The impact of the menstrual cycle on the alpha EEG reactivity to eyes opening (Berger effect) was studied in relation to hormonal and EMG indices. Repeated measurements of salivary progesterone and cortisol, forehead EMG, and EEG alpha-activity indices in 76 healthy women aged 18-27 were obtained in resting eyes closed (1min) and eyes open (30s) conditions. Ten recording sessions occurred, at 2-3day intervals, during 1-2 menstrual cycles. For example, if a participant had a menstrual cycle length of 30-32days, she could finish the investigation during 1cycle, but if she had a 24day cycle, she would finish the investigation over 1 1/2cycles. 6 women extended their investigation into a second cycle. The personal points of each woman's phase data were averaged before being used in group analyses. EEG and EMG responses to eyes open showed that magnitude of α-1 amplitude suppression corresponds to increasing EMG and salivary cortisol concentration only at the Follicular phase, when low alpha frequency waves are dominant in combination with low progesterone level. The magnitude of alpha suppression in response to eyes open in the upper α-2 frequency range does not vary with the menstrual cycle. The Luteal phase corresponds to the highest level of salivary progesterone and is associated with enhancement of the α-bandwidth. The most prominent reaction of salivary cortisol level, forehead EMG, and alpha EEG power to opening of the eyes occurs in the Follicular phase. This research reveals the dependence of the EEG Berger effect on the hormonal state and EEG alpha frequency., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The phasic orienting reflex (OR) was investigated in two counterbalanced blocks of an auditory dishabituation paradigm differing in stimulus Significance (operationalised as tone counting). Twelve tones were presented at very long, randomly-varying interstimulus intervals (ISIs). Novelty and Significance were varied within subjects. Stimulus-response patterns were assessed to find ERP matches for autonomic measures. The phasic OR index was represented by the skin conductance response (SCR). SCR decremented over 10 standard trials, showed recovery on trial 11 (change trial), enhancement to re-presentation of the standard tone (trial 12: dishabituation), and a main effect of Significance over the first 10 trials - demonstrating the formal criteria for an OR index. The evoked cardiac response (HR) subcomponents ECR1 (deceleration) and ECR2 (acceleration) showed no trial effects, but ECR2 showed a Significance effect. Respiratory pause (RP) decreased linearly over trials, and showed recovery, but no dishabituation or Significance effect. Temporal PCA was applied to single-trial EOG-corrected data. Ten ERP components were extracted: P1, N1-3, N1-1, PN, P2, P3a, P3b, HabP3, a Frontal Slow Wave (FSW), and the Classic SW. The dependent measures showed 4 distinct patterns. Pattern 1: No trial or Significance effects (ECR1, P1, N1-3, P3a, FSW); Pattern 2: No trial effect but a Significance effect (ECR2, N1-1, P2); Pattern 3: Trial but not Significance effects (RP, PN, P3b, HabP3); Pattern 4: Both trial and Significance effects (SCR and Classic SW). The evidenced fractionation of autonomic and central measures is compatible with Preliminary Process Theory (PPT), contrary to the notion of a unitary OR., (Copyright © 2017 Elsevier B.V. All rights reserved.)

We explored the separation of Go and NoGo effects in the ERP components elicited in an equiprobable Go/NoGo task, using different forms of temporal Principal Components Analysis (PCA). Following exploratory simulation studies assessing the PCA impact of latency jitter and between-condition latency differences in the P3 latency range, an empirical study compared results of a Combined PCA carried out using both Go and NoGo ERPs together as input, with those from two Separate PCAs carried out on the Go and NoGo ERPs separately. The simulation studies indicated that Separate PCAs provide adequate component recovery in the presence of P3 latency jitter, and that Combined PCAs provide good separation of components only when systematic condition-related latency differences are sufficiently large (here ~110ms). In the empirical data, broadly-similar components were obtained from the Combined and Separate PCAs, supporting previous findings from Combined PCA investigations, and the consequent interpretations of the sequential processing involved. However, the Separate PCAs generated latency differences for components in the Go and NoGo processing chains that better matched the late Go/NoGo ERP peaks, and produced better-defined and larger components that fitted the stages in a hypothetical processing schema developed for this paradigm. Overall, the Separate PCAs yielded a better partitioning of the ERP variance associated with the Go and NoGo conditions, and should be considered as the first choice in future investigations if systematic component or subcomponent latency differences are present or suspected., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Objective: We recently proposed a sequential processing schema for the equiprobable auditory Go/NoGo task, based on a principal components analysis (PCA) of event-related potentials (ERPs) from a university student sample. Here we sought to replicate the schema, and use it to explore processing in well-functioning older adults., Methods: We compared behavioural responding and ERPs of 20 independent-living older adults (Mage=68.2years) to data from a sex- and handedness-matched group of university students (Mage=20.4years). ERPs had substantial latency differences between the groups, and hence were subjected to separate group temporal PCAs., Results: Component latencies were systematically increased in the older group by some 26%, with no significant increase in RT or error rates. Despite some differences in their identified components, each group displayed differential component responsivity to Go versus NoGo; this was reduced in the older participants., Conclusion: The results support our processing schema, and provide insight into the processing stages in well-functioning older adults., Significance: Understanding the perceptual and cognitive processing stages in normal ageing is a pre-requisite for research on mild cognitive impairment and dementia. This study may also provide a simple paradigm and schema suitable for further exploration of functionality in ageing., (Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: This study investigated differences in EEG coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (AD/HD) - one with the more common EEG profile (increased theta), and a group with excess alpha activity as the dominant EEG abnormality., Methods: 26 children (aged 9-13years) with AD/HD were included in each of the excess-theta and excess-alpha groups, and were age- and sex-matched with 26 control subjects. EEG was recorded from 19 electrode sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric and eight interhemispheric electrode pairs, for the delta, theta, alpha and beta bands., Results: In comparison with the controls, the excess-theta AD/HD group had increased theta intrahemispheric coherences at short-medium inter-electrode distances. Frontally, the excess-theta AD/HD group had increased interhemispheric theta and reduced beta coherences. The excess-alpha group primarily showed increased slow wave (delta and theta) intrahemispheric coherence at short-medium inter-electrode distances, and reduced alpha coherence at longer inter-electrode distances, compared with controls. An increase in frontal interhemispheric theta coherence was also found., Conclusions: These results suggest that AD/HD children with excess alpha power have an underlying connectivity dysfunction in the frontal lobes, which is found in common with other subjects with the excess-theta EEG profile. However, a number of qualitative differences exist that could be associated with other aspects of the AD/HD diagnosis. The excess-alpha group appeared to have fewer frontal-lobe abnormalities than the excess-theta AD/HD group., Significance: This is the first study to investigate coherence in AD/HD children who have the atypical profile of increased alpha power in their EEG., (Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: This study investigated differences in the EEG power and coherence of children with Asperger's Syndrome., Method: Twenty boys with Asperger's Syndrome, aged 7-12 years, and an age and sex matched control group, participated in this study. The EEG was recorded during an eyes-closed resting condition from 19 electrode sites, which were clustered into nine regions prior to analysis. One minute of trace was analysed using Fourier transformations to obtain both absolute and relative power estimates in the delta, theta, alpha and beta frequency bands. Wave-shape coherence was calculated for 8 intrahemispheric and 8 interhemispheric electrode pairs., Results: The Asperger's group had a global increase in absolute delta and an anterior increase in relative delta. Both absolute and relative theta were globally increased and relative alpha was globally decreased. Subjects with Asperger's Syndrome exhibited a broad pattern of reduced hemispheric asymmetry in intrahemispheric coherence. Reduced anterior interhemispheric coherence in the alpha and beta bands was also found in the Asperger's Syndrome group., Conclusions: These results suggest the existence of frontal lobe abnormalities in children with Asperger's Syndrome, and possible abnormalities in normal CNS maturational processes., Significance: This is the first major study to investigate EEG power and coherence anomalies in children with Asperger's Syndrome., (Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

The phasic orienting reflex (OR) was investigated using single-trial data collected concurrently from 4 autonomic measures and event-related potentials (ERPs). In an auditory dishabituation paradigm, twelve indifferent tones of two intensities (60 or 80 dB, intensity change on trial 11, counterbalanced between subjects) were presented at very long interstimulus intervals (ISIs). Novelty and intensity based stimulus-response patterns were examined seeking ERP analogues of autonomic measures representing pre-OR and OR processing. Skin conductance response (SCR) represented the phasic OR index. EOG-corrected ERP data for 16 subjects were decomposed by a temporal Principal Components Analysis (PCA). SCR diminished over 10 standard trials, recovered on change trial 11, dishabituated to the re-presentation of the standard tone on trial 12, and showed intensity effects at the change - formal requirements for an OR index. The evoked cardiac response (HR) showed no trial or intensity effects. Respiratory pause (RP) decreased linearly over trials and showed recovery but no dishabituation or intensity effect. Peripheral vasoconstriction (PVC) failed to decrement but exhibited an intensity effect. Ten identifiable ERP components were extracted: Na, P1, N1-1, PN, P2, P3a, P3b, a novelty-sensitive HabP3, an intensity-sensitive IntP3, and the Slow Wave (SW). Pattern 1 showed no trial or intensity effects (HR, P1, PN, P2); Pattern 2 showed no trial effect but an intensity effect (PVC, Na, N1-1, P3a); and Pattern 3 demonstrated habituation and an intensity effect (SCR, RP, P3b, HabP3, IntP3, SW). The observed fractionation of autonomic and central measures is consistent with Preliminary Process Theory (PPT) rather than the notion of a unitary OR., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A recent series of studies of the auditory equiprobable Go/NoGo task, using fixed interstimulus intervals (ISIs), proposed a processing schema relating observed event-related potential (ERP) components to sequential processing stages. However, it has been demonstrated that attention and ERP components can be affected by the predictable rhythmic timing of fixed ISIs. Hence the aim of the current study was to test the robustness of that processing schema with an unpredictable arrhythmic variable ISI. EEG was recorded from 30 university students at 30 scalp sites in an unwarned auditory equiprobable Go/NoGo task using a variable ISI. Following our previous studies, Go and NoGo ERP components were derived using temporal principal components analysis (PCA). Of the unrestricted Varimax-rotated factors, seven were identifiable as components based on their topography, polarity, and latency: two subcomponents of the N1 (N1-1, and processing negativity, PN), P2/N2b, N2c/P3a, P3b, and two subcomponents of the slow wave (SW-1 and SW-2). These components showed Go/NoGo effects comparable to those previously noted with fixed ISI, supporting the proposed processing schema. The Late Positivity (LP) component, previously speculated to mark cortical deactivation after processing the NoGo stimulus, was not present in the sequence of components. In its absence, activity underlying the observed sustained P300/late positive complex may be involved in processing temporally-uncertain stimuli., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Objective: To investigate whether the latent neural correlates of incentive processing differ between problem gamblers (PGs) and healthy controls (HCs)., Methods: Event-related potential (ERP) data were derived while 16 PGs and 20 HCs played a computer electronic gaming machine (EGM) task. Psychophysiological responses to outcomes commonly encountered during EGM gambling, including Large wins, Small wins, Near-wins, and Losses, were examined using a spatiotemporal principal components analysis (PCA). Subjects also completed questionnaires that assessed their levels of impulsivity, attraction to appetitive stimuli, and avoidance of aversive stimuli., Results: Losses elicited a feedback-related negativity (FRN), whereas wins elicited a feedback-related positivity (FRP) at the same latency and topography. PGs exhibited both attenuated FRN amplitudes following Losses and FRP amplitudes following Wins. Greater P3b amplitudes were found following Wins compared to Losses. FRN amplitudes following Near-wins were significantly reduced compared to Losses for both PGs and HCs. Trends for reduced P3b amplitudes following all outcome types, and for similar P3b amplitudes following Large and Small wins, were found for the PG group., Conclusions: We provide evidence that PGs are hyposensitive to both positive and negative outcomes., Significance: The finding that PGs are hyposensitive to reward and punishment provides valuable insight into the nature of deficit in this disorder, and provides a foundation for future research and clinical interventions., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)