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The objective of this study was to compare the development of sleepiness during manual driving versus level 2 partially automated driving, when driving on a motorway in Sweden. The hypothesis was that partially auto-mated driving will lead to higher levels of fatigue due to underload. Eighty-nine drivers were included in the study using a 2 ? 2 design with the conditions manual versus partially automated driving and daytime (full sleep) versus night-time (sleep deprived). The results showed that night-time driving led to markedly increased levels of sleepiness in terms of subjective sleepiness ratings, blink durations, PERCLOS, pupil diameter and heart rate. Partially automated driving led to slightly higher subjective sleepiness ratings, longer blink durations, decreased pupil diameter, slower heart rate, and higher EEG alpha and theta activity. However, elevated levels of sleepiness mainly arose from the night-time drives when the sleep pressure was high. During daytime, when the drivers were alert, partially automated driving had little or no detrimental effects on driver fatigue. Whether the negative effects of increased sleepiness during partially automated driving can be compensated by the positive effects of lateral and longitudinal driving support needs to be investigated in further studies. Funding Agencies|ADASME [688900]; Mediator projects - European Unions Horizon 2020 research and innovation programme [814735]; Autoliv Development; SmartEye AB

In two separate recent studies, researchers have reported an association between increases in children's shyness (i.e., social avoidance and inhibition) and decreases on frontal baseline electroencephalogram (EEG) alpha-to-delta ratio (ADR) scores (i.e., Schmidt & Poole, 2018, 2020). Here we attempted to extend these findings by examining whether different types of children's shyness were distinguishable on this same frontal ADR score, which is thought to be one electrocortical proxy of brain maturation. We coded expressions of positive shyness (i.e., co-occurrence of smiling and avoidance behaviors) versus non-positive shyness (i.e., avoidance behaviors) from direct observations during a social presentation speech in children (N = 63; Mage = 10.41 years) and examined these expressions of shyness in relation to the children's frontal baseline EEG ADR scores. We found preliminary evidence that children expressing positive shyness exhibited the lowest frontal baseline EEG ADR score (i.e., ostensibly less brain maturation) relative to children expressing non-positive shyness and low levels of shyness. We speculate that relatively less frontal brain maturation may be linked to some adaptive features of shyness.

Background EEG mu rhythm suppression is assessed in experiments on the execution, observation and imagination of movements. It is utilised for studying of actions, language, empathy in healthy individuals and preservation of sensorimotor system functions in patients with schizophrenia and autism spectrum disorders. While EEG alpha and mu rhythms are recorded in the same frequency range (8−13 Hz), their specification becomes a serious issue. The new method is based on the spatial and functional characteristics of the mu wave, which are: (1) the mu rhythm is located over the sensorimotor cortex; (2) it desynchronises during movement processing and does not respond on the eyes opening. In EEG recordings, we analysed the mu rhythm under conditions with eyes opened and eyes closed (baseline), and during a motor imagery task with eyes closed. EEG recordings were processed by principal component analysis (PCA). Results The analysis of EEG data with the proposed approach revealed the maximum spectral power of mu rhythm localised in the sensorimotor areas. During motor imagery, mu rhythm was suppressed more in frontal and central sites than in occipital sites, whereas alpha rhythm was suppressed more in parietal and occipital sites. Mu rhythm desynchronization in sensorimotor sites during motor imagery was greater than alpha rhythm desynchronization. The proposed method enabled EEG mu rhythm separation from its mix with alpha rhythm. Conclusions EEG mu rhythm separation with the proposed method satisfies its classical definition.

Mindfulness meditation (MM) and EEG-alpha neurofeedback (NFB) have both been shown to improve attentional performance and increase full 8–12-Hz EEG alpha amplitude, but no studies have compared MM and NFB on their effects for modulating EEG alpha or attentional control. Sixty-one university students were randomized to a 15-min single-session MM (n = 24), NFB (n = 17), or sham-NFB (SHAM; n = 20) intervention and were compared on EEG alpha full and sub-band amplitudes during completion of a single 15-min session of either intervention across 5 successive 3-min epochs, as well as during performance of the Stroop test. MM and NFB participants demonstrated higher global full-band alpha amplitude when compared with SHAM participants during the final intervention epoch, whereas no group differences were observed for sub-band amplitudes. In the absence of group differences in behavioral performance, MM participants exhibited a lower ERD of the upper alpha-band within frontal cortex 200–400 ms post-stimulus on the Stroop task, an effect that correlated with upper alpha amplitudes demonstrated during the intervention. Future research directions are discussed.

Objective The present study examined whether neural indices of working memory maintenance differ between young adults with ADHD and their healthy peers (Study 1), and whether this neural index would change after working memory training (Study 2). Methods Study 1 involved 136 college students with ADHD and 41 healthy peers (aged 18–35 years) and measured their posterior alpha activity during a visual delayed-match-to-sample task using electroencephalography (EEG). Study 2 involved 99 of the participants with ADHD who were randomized into a standard-length or shortened-length Cogmed working memory training program or a waitlist control group. Results The ADHD group tended to be less accurate than the peers. Similarly, the ADHD group exhibited lower posterior alpha power at a trend level compared to their healthy peers. There were no training effects on participants’ performance and only marginal increases in posterior alpha power in training groups compared to the waitlist group. Conclusions Considering that the training effects were small and there was no load and dose effect, we conclude that the current study provides no convincing evidence for specific effects of Cogmed. Significance These findings provide unique insights into neuroplasticity, or lack thereof, with near-transfer tasks in individuals with ADHD.

Changes in the power and coherence of α-activity and heart rate variability (HRV) were studied in students with different performance levels in logical tasks. In those students who reached high scores in the cognitive tests, we observed higher lability of α-activity and HRV; the values and their ratios varied among the stages of intellectual activity. In these subjects, a decrease in the spectral power of α-band was more pronounced than in other groups. We also observed changes in the interhemispheric coherence and in the structure of coherent interactions in the α-range at different stages of task performance. In contrast, the number and structure of coherent interactions in individuals who showed lower results did not significantly vary at different stages of task performance. As compared with this group, the students with higher test results showed a more pronounced decrease in the total spectral power (TP) and an increase in the low frequency/high frequency (LF/HF) ratio which returned to the initial level after the end of the tests. In students with better results in these cognitive tests, the dynamics of RRNN, TP, HF, and LF/H F during task performance correlated with the dynamics of interhemispherical α-band coherence.

Previous research has indicated that in several domains, women and men may use different cognitive processes along with different neurophysiological activation to achieve similar behavioral performance. The present study extended this line of research to the novel field of soccer playing. In female and male active soccer players, we investigated patterns of brain activation and functional connectivity of brain networks during imagination of creative soccer moves, using EEG methods that are well established in creativity research. Participants were presented with scenarios taken from real soccer games. Female and male soccer players showed comparable creative performance in their imagined moves to score a goal, which was rated by top qualified experts (UEFA A licensed soccer coaches). Notwithstanding, they differed with respect to their brain activation and functional connectivity of brain networks. While men exhibited relatively higher parietal/occipital task-related EEG alpha power, women showed significantly higher within-hemisphere functional coupling in the upper alpha band. The findings add important new evidence to the field of cognitive gender research in an applied, sports-related domain of creative cognition.

This study was designed to assess whether the combined effect of taste-congruent and incongruent extrinsic visual cues presented in virtual reality (VR) influences the perception of sweetness and product liking. Three VR environments (sweet-congruent, sweet-incongruent, and neutral) were created based on the evidence in existing literature. Participants tasted the same beverage in three VR environments and evaluated the environment and beverage liking, as well as perceived taste intensity (sweetness, sourness, and bitterness), congruency, comfort, and environment vividness. Frontal EEG alpha asymmetry (FAA) was also recorded as a complementary physiological measurement of overall liking. The results showed that the perceived sweetness of the beverage was significantly elevated in a sweet-congruent environment versus the other environments. Visual-taste congruency did not seem to have an effect on beverage liking and overall liking, whereas an increase in environment liking was found in the incongruent environment versus the other environments. These findings confirmed the significant influence of taste-specific visual cues on flavour perception, while the successful use of VR in the study provided insight into future applications of taste-specific VR environment in the modulation of flavour perception and sugar reduction.

While electroencephalogram (EEG) alpha desynchronization has been related to anticipatory orienting of visuospatial attention, an increase in alpha power has been associated to its inhibition. A separate line of findings indicated that alpha is affected by a deficient oxygenation of the brain or hypoxia, although leaving unclear whether the latter increases or decreases alpha synchronization. Here, we carried out an exploratory study on these issues by monitoring attention alerting, orienting, and control networks functionality by means of EEG recorded both in normoxia and hypoxia in college students engaged in four attentional cue-target conditions induced by a redesigned Attention Network Test. Alpha power was computed through Fast Fourier Transform. Regardless of brain oxygenation condition, alpha desynchronization was the highest during exogenous, uncued orienting of spatial attention, the lowest during alerting but spatially unpredictable, cued exogenous orienting of attention, and of intermediate level during validly cued endogenous orienting of attention, no matter the motor response workload demanded by the latter, especially over the left hemisphere. Hypoxia induced an increase in alpha power over the right-sided occipital and parietal scalp areas independent of attention cueing and conflict conditions. All in all, these findings prove that attention orienting is undergirded by alpha desynchronization and that alpha right-sided synchronization in hypoxia might sub-serve either the effort to sustain attention over time or an overall suppression of attention networks functionality.

This paper presents Mindgame, a reinforcement learning optimized neurofeedback mindfulness system. To avoid the potential bias and difficulties of designing mapping between neural signal and output, we adopt a trial-and-error learning method to explore the preferred mapping. In a pilot study we assess the effectiveness of Mindgame in mediating people's EEG alpha band. All participants' alpha band change towards the desired direction.

To investigate human brain activities regarding EEG signal during psychophysiological activities in Salat (Muslim Prayer), several facts have been analyzed in this study. This research work investigated relaxed condition with eyes open and eyes closed and compared with 2 raqat (a single unit of Muslim prayer) Salat. Consequently, we have proposed that Salat provides a more relaxed state of mind than that of relaxing with either eye opened or closed. EEG data were acquired through the B-Alert system from several participants. The effects of EEG alpha band were determined using Welch's power spectral density method. Using student's t-distribution, the p-value was calculated to determine the difference between the alpha relative power of Salat and other relaxed states. During psychophysiological activities in Salat, a significant (p

We use a unique environment of Whole Body Perceptual Deprivation (WBPD) to induce an altered state of consciousness (ASC) in our participants, and employ online EEG recording. We present individual EEG alpha profiles, and show how these data can be analyzed at the individual level. Our goal is to investigate to what degree subjective experience matches EEG alpha profile, and in particular, the various alpha hemispheric asymmetries observed in the frontal, parietal, and occipital lobes. Specifically, we consider positive (frontal LR) or negative (frontal LR) affect; a more verbal (LR) or a more imagistic (RL) mode of thinking; and a more trancelike (frontalparietal) or more reflective (frontalparietal) state of consciousness. Our results indicate that the individual alpha profiles are reflected in individual differences in subjective experience. However, the alpha profiles are confounded with the gender of the participant. Specifically, there is a predominant RL asymmetry found for male participants, and a predominant LR asymmetry found for female participants.

In a community-based sample of 104 infants and their mothers, we hypothesized a pathway from postnatal maternal symptoms of depression to child emotion dysregulation, and tested at 6 months of age the mediation role of alpha asymmetry at frontal and parietal sites. We recorded infant resting-state EEG at 6 months of age. Child emotion dysregulation was measured at 24 months by the Child Behavior Checklist Dysregulation Profile derived from the CBCL 1½-5. Maternal depression symptoms were scored 6 months after the delivery by the Anxious/Depressed scale of the Adult Self-Report. We used structural equation modeling to test the mediation model from maternal depression symptoms to child emotion dysregulation mediated by frontal and parietal alpha asymmetry. The mediation model provided an excellent fit to the data [χ2(3) = 3.088, p = .378; RMSEA = .017, CFI = .1.00; SRMR = 0.040] and explained 23.3% of the variance in child emotion dysregulation. The indirect path via parietal alpha asymmetry was significant (β = .065; SE = .033; 95% CI = .001–.139; p = .048), i.e. greater levels of maternal depression symptoms predicted left parietal alpha asymmetry, which predicted higher levels of child emotion dysregulation. The direct effect, i.e. the pathway linking maternal depression symptoms and child emotion dysregulation above and beyond the indirect effects, was also significant. We found evidence for a partial mediation role of left parietal alpha asymmetry in a longitudinal pathway from postnatal maternal symptoms of depression to child emotion dysregulation, providing support for left parietal asymmetry as an index of biological vulnerability to emotion dysregulation in the first years of life.

Affective dispositions may shape students' typical ways of coping when faced with demanding performance situations in their educational lives. We recorded frontal EEG alpha asymmetry responses in psychology students (n = 62) during the course of a scenario designed to simulate a real examination, which required oral explanation of statistical concepts. While students with lower levels of trait positive affect (PANAS) showed relative right hemispheric activation, sustained relative left hemispheric activation was observed in students with higher levels of trait positive affect. In line with relevant models of frontal brain asymmetry, the findings suggest that students' coping behaviors in the context of academic performance situations are in part instantaneously initiated, which is reflected in spontaneous activation of relative approach versus avoidance motivation. Independently of negative affect and momentary affective states, trait positive affectivity seems to be linked to recruitment of brain processes supporting a more adaptive response in that matter.

In the previous study, the EEG data features which comprise of relaxed and non-relaxed conditions were clustered to a group of three, four and five using Fuzzy C-Means. Alpha waves were selected and collected from the pre-frontal right and prefrontal left, computed into alpha asymmetry to become as the EEG features. To ensure which data features in the clusters showed a significant difference, p

Objective Greater relative right- than left-frontal cortical activity has been frequently found in adults with major depression (MD). As the few studies in adolescents with MD have been inconclusive, the aim of this study was to assess frontal alpha asymmetry (FAA) in an adolescent sample with MD whilst taking into account possible confounding variables such as disease state and comorbid anxiety disorder. Methods An 8-minute resting frontal EEG was assessed in 34 healthy controls (HCs), 16 adolescents with MD in remission without comorbid anxiety disorder (rMDa−), 22 adolescents with acute depression without comorbid anxiety disorder (MDa−), and 23 adolescents with acute depression and comorbid anxiety disorder (MDa+). Alpha power was analyzed over corresponding frontal Regions of Interests. Results Compared to HCs, MDa+ adolescents demonstrated more left- than right-sided EEG alpha power, indicating greater right-than left-frontal cortical activity. No other group differences emerged. Conclusions The results suggest that greater relative right-frontal cortical activity in adolescent MD is not a result of disease state but can be attributed to comorbid anxiety disorder. Significance Results suggest that FAA is not linked to adolescent depression per se and highlight the importance of considering comorbid disorders when examining asymmetry patterns in adolescent MD.

Nonlinear analysis of EEG recordings allows detection of characteristics that would probably be neglected by linear methods. This study aimed to determine a suitable epoch length for nonlinear analysis of EEG data based on its recurrence rate in EEG alpha activity (electrodes Fz, Oz, and Pz) from 28 healthy and 64 major depressive disorder subjects. Two nonlinear metrics, Lempel-Ziv complexity and scaling index, were applied in sliding windows of 20 seconds shifted every 1 second and in nonoverlapping windows of 1 minute. In addition, linear spectral analysis was carried out for comparison with the nonlinear results. The analysis with sliding windows showed that the cortical dynamics underlying alpha activity had a recurrence period of around 40 seconds in both groups. In the analysis with nonoverlapping windows, long-term nonstationarities entailed changes over time in the nonlinear dynamics that became significantly different between epochs across time, which was not detected with the linear spectral analysis. Findings suggest that epoch lengths shorter than 40 seconds neglect information in EEG nonlinear studies. In turn, linear analysis did not detect characteristics from long-term nonstationarities in EEG alpha waves of control subjects and patients with major depressive disorder patients. We recommend that application of nonlinear metrics in EEG time series, particularly of alpha activity, should be carried out with epochs around 60 seconds. In addition, this study aimed to demonstrate that long-term nonlinearities are inherent to the cortical brain dynamics regardless of the presence or absence of a mental disorder.

An experimentally tested neural field theory of the corticothalamic system is used to model brain activity and resulting experimental EEG data, and to elucidate the neural mechanisms and physiological basis of alpha-BOLD anticorrelation observed in concurrent EEG and fMRI measurements. Several studies have proposed that the anticorrelation originates from a causal link between changes in the alpha power and BOLD signal. However, the results in this study reveal that fluctuations in alpha and BOLD power do not generate one another but instead respectively result from high- and low-frequency components of the same underlying cortical activity, and that they are inversely correlated via variations in the strengths of corticothalamic and intrathalamic feedback, thereby explaining their anticorrelation.

Objective We previously identified posterior EEG alpha as a potential biomarker for antidepressant treatment response. To meet the definition of a trait biomarker or endophenotype, it should be independent of the course of depression. Accordingly, this report evaluated the temporal stability of posterior EEG alpha at rest. Methods Resting EEG was recorded from 70 participants (29 male; 46 adults), during testing sessions separated by 12 ± 1.1 years. EEG alpha was identified, separated and quantified using reference-free methods that combine current source density (CSD) with principal components analysis (PCA). Measures of overall (eyes closed-plus-open) and net (eyes closed-minus-open) posterior alpha amplitude and asymmetry were compared across testing sessions. Results Overall alpha was stable for the full sample (Spearman-Brown [ r SB ] = .834, Pearson's r = .718), and showed excellent reliability for adults ( r SB = .918; r = 0.848). Net alpha showed acceptable reliability for adults ( r SB = .750; r = .600). Hemispheric asymmetries (right-minus-left hemisphere) of posterior overall alpha showed significant correlations, but revealed acceptable reliability only for adults ( r SB = .728; r = .573). Findings were highly comparable between 29 male and 41 female participants. Conclusions Overall posterior EEG alpha amplitude is reliable over long time intervals in adults. Significance The temporal stability of posterior EEG alpha oscillations at rest over long time intervals is indicative of an individual trait.

Neurophysiological correlates of affective experience could potentially provide continuous information about a person’s experience when cooking and tasting food, without explicitly verbalizing this. Such measures would be helpful to understand people’s implicit food preferences and choices. This study examined for the first time the relation between neurophysiological variables and affective experiences under real cooking and tasting circumstances, using ingredients that were a priori expected to evoke different affective reactions. 41 participants cooked and tasted two stir-fry dishes in random order following an identical, strictly timed protocol. Once the main ingredient was chicken and the other time mealworms. EEG, ECG and skin potential were recorded continuously. Participants scored subjective valence and arousal after each cooking and tasting session. Frontal EEG alpha asymmetry showed the expected effect throughout the whole cooking and tasting session, consistent with ‘approach’ motivation for chicken and ‘avoidance’ for mealworms. Skin potential effects differed between cooking intervals but were in the expected direction. ECG variables showed an interaction with order of cooking the different dishes. Based on EEG alpha asymmetry, ECG and skin potential variables, we can estimate with 82% accuracy whether a single participant is preparing a dish with mealworms or with chicken. Our study provides evidence that it is possible to estimate experienced emotion during real-life cooking and tasting. We argue that it is important to consider that different neurophysiological and subjective measures reflect different underlying affective processes, to map them out more precisely, and to take advantage of these differences.

Resting and task-related EEG alpha are used in studies of cognition and psychopathology. Although Laplacian methods have been applied, apprehensions about loss of global activity dissuade researchers from greater use except as a supplement to reference-dependent measures. The unfortunate result has been continued reliance on reference strategies that differ across labs, and a systemic preference for a montage-dependent average reference over true reference-free measures. We addressed these concerns by comparing resting- and task-related EEG alpha using three EEG transformations: nose- (NR) and average-referenced (AR) EEG, and the corresponding CSD. Amplitude spectra of resting and prestimulus task-related EEG (novelty oddball) and event-related spectral perturbations were scaled to equate each transformation. Alpha measures quantified for 8–12 Hz bands were: 1) net amplitude (eyes-closed minus eyes-open) and 2) overall amplitude (eyes-closed plus eyes-open); 3) task amplitude (prestimulus baseline) and 4) task event-related desynchronization (ERD). Mean topographies unambiguously represented posterior alpha for overall, net and task, as well as poststimulus alpha ERD. Topographies were similar for the three transformations, but differed in dispersion, CSD being sharpest and NR most broadly distributed. Transformations also differed in scale, AR showing less attenuation or spurious secondary maxima at anterior sites, consistent with simulations of distributed posterior generators. Posterior task alpha and alpha ERD were positively correlated with overall alpha, but not with net alpha. CSD topographies consistently and appropriately represented posterior EEG alpha for all measures.

Previous studies on insight problem solving using Chinese logogriphs as insight problems only investigated the time- and phase-locked changes of electrocortical responses triggered by Chinese logogriphs, but did not focus on what kind of brain state facilitates individuals to solve insight problems. To investigate this, we focused on participants' alpha activities (8-12 Hz) that closely correlates with insight problem solving and defocused attention while they were solving Chinese logogriphs. Results indicated that in the time window of 800-1400 ms after the presentation of target logogriphs, alpha power over parieto-central electrodes decreased relative to the reference interval in both the successful and unsuccessful logogriphs solving conditions. However, alpha power increased at parieto-occipital electrode sites in successful conditions compared with that in unsuccessful condition. The decrease in alpha activity in both conditions may reflect the cognitive demands in solving the target logogriphs. Furthermore, difference in alpha power between the successful and unsuccessful conditions at parieto-occipital electrode sites is associated with the process of heuristic information. Alpha synchronization observed in the successful condition compared to the unsuccessful condition might reflect a state of defocused attention that facilitates insight problem solving.

The beneficial effects of placebo treatments on fear and anxiety (placebo anxiolysis) are well known from clinical practice, and there is strong evidence indicating a contribution of treatment expectations to the efficacy of anxiolytic drugs. Although clinically highly relevant, the neural mechanisms underlying placebo anxiolysis are poorly understood. In two studies in humans, we tested whether the administration of an inactive treatment along with verbal suggestions of anxiolysis can attenuate experimentally induced states of phasic fear and/or sustained anxiety. Phasic fear is the response to a well defined threat and includes attentional focusing on the source of threat and concomitant phasic increases of autonomic arousal, whereas in sustained states of anxiety potential and unclear danger requires vigilant scanning of the environment and elevated tonic arousal levels. Our placebo manipulation consistently reduced vigilance measured in terms of undifferentiated reactivity to salient cues (indexed by subjective ratings, skin conductance responses and EEG event-related potentials) and tonic arousal [indexed by cue-unrelated skin conductance levels and enhanced EEG alpha (8–12 Hz) activity], indicating a downregulation of sustained anxiety rather than phasic fear. We also observed a placebo-dependent sustained increase of frontal midline EEG theta (4–7 Hz) power and frontoposterior theta coupling, suggesting the recruitment of frontally based cognitive control functions. Our results thus support the crucial role of treatment expectations in placebo anxiolysis and provide insight into the underlying neural mechanisms.

International audience; Insomniacs report decreased performance in daily routines, which may have detrimental consequences for car driving. We compared changes over time in driving performance (measured as Standard Deviation of Lateral Position – SDLP) and background EEG between 20 untreated insomnia patients (52–70 years old) and 21 normal sleepers (54–73 years old) during a 1 h on-the-road driving test after a normal night of sleep, in the morning. SDLP did not differ between groups and increased slightly over time to similar degrees in both groups. EEG alpha and beta power were lower in insomniacs as compared to normal sleepers. Alpha and beta power slightly reduced during driving in normal sleepers but remained at a constant low level in insomniacs. Changes in EEG power and SDLP were not related. It is concluded that on-the-road driving performance does not differ between older insomniacs and older normal sleepers and that changes in spectral EEG measures of cortical arousal and in driving performance are not related.

Working memory (WM) capacity affects our daily life in many ways, and its decrease often associates with neural disorders (e.g. Alzheimer's disease). Several studies have confirmed that alpha rhythms play an active role in memory mechanism. In the present study, we designed a digit verbal span experiment to find out that how the alpha power change during working memory encoding, and the relationship between alpha power and individual WM performance. Consistent with previous studies, our results confirm that alpha power is positively related to WM performance. Participants who had higher alpha power during WM encoding achieved better memory performance. We can conclude that the reason is alpha rhythms reflect inhibition of task-irrelevant information. Howbeit, a linear relationship between WM load and alpha power amplitude during memory encoding cannot be deduced in our experiment.

Pre-stimulus phase has been shown to influence temporal judgments concerning order, causality and simultaneity. One hypothesis is that phase cycles frame discrete perceptual snapshots over time. Yet, existing studies have explored the effect of pre-stimulus phase on fine-grained temporal judgments whereas no study has shown whether pre-stimulus phase influences subsecond temporal judgments lasting several phase cycles. If effects of phase on fine-grainedtemporal judgments reflect perceptual framing, then the perception of longer intervals might show some dependency on the frequency of phase cycles. Higher frequencies should promote increased temporal resolution and discrimination. We tested the relationship between the phase and frequency of oscillations and temporal judgments for longer durations. Participants judged the relative duration of two successive intervals lasting several phase cycles each. Pre-stimulus alpha-band and beta-band phase was associated with subsequent temporal judgments, although not sensitivity, therein providing evidence that pre-stimulus phase is related to temporal judgments that span a longer time-scale than has been previously demonstrated. Although we report evidence that peak-frequency of the alpha-band is related to one measure of task performance, this study does not provide evidence that higher peak frequencies of alpha- or beta-band activity are related to improved duration discrimination of longer intervals.

Conscious experiences are linked to activity in our brain: the neural correlates of consciousness (NCC). Empirical research on these NCCs covers a wide range of brain activity signals, measures, and methodologies. In this paper, we focus on spontaneous brain oscillations; rhythmic fluctuations of neuronal (population) activity which can be characterized by a range of parameters, such as frequency, amplitude (power), and phase. We provide an overview of oscillatory measures that appear to correlate with conscious perception. We also discuss how increasingly sophisticated techniques allow us to study the causal role of oscillatory activity in conscious perception (i.e., ‘entrainment’). This review of oscillatory correlates of consciousness suggests that, for example, activity in the alpha-band (7–13 Hz) may index, or even causally support, conscious perception. But such results also showcase an increasingly acknowledged difficulty in NCC research; the challenge of separating neural activity necessary for conscious experience to arise (prerequisites) from neural activity underlying the conscious experience itself (substrates) or its results (consequences).

Conscious experiences are linked to activity in our brain: the neural correlates of consciousness (NCC). Empirical research on these NCCs covers a wide range of brain activity signals, measures, and methodologies. In this paper, we focus on spontaneous brain oscillations; rhythmic fluctuations of neuronal (population) activity which can be characterized by a range of parameters, such as frequency, amplitude (power), and phase. We provide an overview of oscillatory measures that appear to correlate with conscious perception. We also discuss how increasingly sophisticated techniques allow us to study the causal role of oscillatory activity in conscious perception (i.e., 'entrainment'). This review of oscillatory correlates of consciousness suggests that, for example, activity in the alpha-band (7-13 Hz) may index, or even causally support, conscious perception. But such results also showcase an increasingly acknowledged difficulty in NCC research; the challenge of separating neural activity necessary for conscious experience to arise (prerequisites) from neural activity underlying the conscious experience itself (substrates) or its results (consequences).

The perceptual processing of emotional stimuli is subject to the regulation of brain function. This study investigated whether frontal electroencephalography (EEG) alpha asymmetry at resting conditions predicted the evaluation of emotional picture stimuli by event-related potentials (ERPs). In this study, participants first completed a 2-min resting task, and then passively viewed emotional pictures. The results showed that left active individuals had smaller frontal EEG alpha asymmetry scores to negative pictures than to positive and neutral pictures, whereas right active individuals had similar frontal EEG alpha asymmetry scores to negative, positive, and neutral pictures. Furthermore, the study showed a larger P300 to negative pictures than to positive and neutral pictures for left active individuals; however, there were no significant ERP differences to negative, positive, and neutral pictures for right active individuals. These findings suggest that frontal EEG alpha asymmetry at resting conditions can reflect interindividual differences in emotional perception tendencies to emotional picture stimuli.

The present study tested whether people adaptively sharpen attentional focus following performance mistakes, as predicted by current theories of cognitive control. Participants completed a reverse Stroop task in which target stimuli were preceded by an informative spatial cue. Cue validity and Stroop interference effects on performance were robust, but neither effect was altered by commission of an error on the prior trial, as predicted by the adaptive control model. Likewise, a prior error did not enhance cue-evoked spatial asymmetries in EEG, nor did it enhance validity effects on neural responses evoked by targets. Instead, errors were followed by poorer overall performance and generalized arousal, as measured by generally suppressed EEG alpha power in postresponse and cue-to-target intervals following errors compared to correct responses. Results support an alternative theory that post-error changes in neural activity and performance reflect arousal, orienting, or cognitive bottlenecking rather than adaptive control of attention.

Electroencephalogram (EEG) contains valuable information obtained noninvasively that can be used for assessment of brain's processing capacity of patients with psychiatric disorders. The purpose of the present work was to evaluate possible differences in EEG complexity between deficit (DS) and nondeficit (NDS) subtypes of schizophrenia as a reflection of the cognitive processing capacities in these groups. A particular nonlinear metric known as Lempel-Ziv complexity (LZC) was used as a computational tool in order to determine the randomness in EEG alpha band time series from 3 groups (deficit schizophrenia [n = 9], nondeficit schizophrenia [n = 10], and healthy controls [n = 10]) according to time series randomness. There was a significant difference in frontal EEG complexity between the DS and NDS subgroups ( p = .013), with DS group showing less complexity. A significant positive correlation was found between LZC values and Positive and Negative Syndrome Scale (PANSS) general psychopathology scores (ie, larger frontal EEG complexity correlated with more severe psychopathology), explained partially by the emotional component subscore of the PANSS. These findings suggest that cognitive processing occurring in the frontal networks in DS is less complex compared to NDS patients as reflected by EEG complexity measures. The data also suggest that there may be a relationship between the degree of emotionality and the complexity of the frontal EEG signal.

Research suggests that midline posterior versus frontal electroencephalographic (EEG) theta activity (PFTA) may reflect a novel neurophysiological index of approach motivation. Elevated PFTA has been associated with approach-related tendencies both at rest and during laboratory tasks designed to enhance approach motivation. PFTA is sensitive to changes in dopamine signaling within the fronto-striatal neural circuit, which is centrally involved in approach motivation, reward processing, and goal-directed behavior. To date, however, no studies have examined PFTA during a laboratory task designed to reduce approach motivation or goal-directed behavior. Considerable animal and human research supports the hypothesis put forth by the learned helplessness theory that exposure to uncontrollable aversive stimuli decreases approach motivation by inducing a state of perceived uncontrollability. Accordingly, the present study examined the effect of perceived uncontrollability (i.e., learned helplessness) on PFTA. EEG data were collected from 74 participants (mean age = 19.21 years; 40 females) exposed to either Controllable (n = 26) or Uncontrollable (n = 25) aversive noise bursts, or a No-Noise Condition (n = 23). In line with prediction, individuals exposed to uncontrollable aversive noise bursts displayed a significant decrease in PFTA, reflecting reduced approach motivation, relative to both individuals exposed to controllable noise bursts or the No-Noise Condition. There was no relationship between perceived uncontrollability and frontal EEG alpha asymmetry, another commonly used neurophysiological index of approach motivation. Results have implications for understanding the neurophysiology of approach motivation and establishing PFTA as a neurophysiological index of approach-related tendencies.

The mechanisms underlying bupropion's efficacy as an antidepressant and a smoking cessation aid are far from being fully characterized. The present study is the first to examine the effects of bupropion on visuospatial task-related parietal EEG alpha power asymmetry-an asymmetry that has previously been found to be associated with severity of depressive symptoms (i.e., the more depressive symptoms, the greater alpha power in the right vs. left parietal area [Henriques & Davidson, 1997; Rabe, Debener, Brocke, & Beauducel, 2005]). Participants, all of whom were smokers and none of whom were clinically depressed, were randomly assigned to the Placebo group (n = 79) or Bupropion group (n = 31) in a double-blind study. EEG during the performance of the visuospatial task was collected before and after 14 days on placebo or bupropion sustained-release capsules. Relative to the Placebo group, the Bupropion group (especially, the Bupropion subgroup who had a positive right versus left parietal alpha power asymmetry at pretreatment) had a reduction in the parietal alpha asymmetry (driven largely by a decrease in right parietal alpha power). These findings support the hypothesis that bupropion can induce changes in parietal EEG asymmetry that have been shown in previous literature to be associated with a reduction in depressive states and traits. (PsycINFO Database Record

A prior report (Tenke et al., 2013 Biol. Psychol. 94:426-432) found that participants who rated religion or spirituality (R/S) highly important had greater posterior alpha after 10 years compared to those who did not. Participants who subsequently lowered their rating also had prominent alpha, while those who increased their rating did not. Here we report EEG findings 20 years after initial assessment. Clinical evaluations and R/S ratings were obtained from 73 (52 new) participants in a longitudinal study of family risk for depression. Frequency PCA of current source density transformed EEG concisely quantified posterior alpha. Those who initially rated R/S as highly important had greater alpha compared to those who did not, even if their R/S rating later increased. Furthermore, changes in religious denomination were associated with decreased alpha. Results suggest the possibility of a critical stage in the ontogenesis of R/S that is linked to posterior resting alpha.

Several studies reveal that unpleasant pictures elicit higher beta and gamma responses than pleasant and/or neutral pictures; however, the effect of stimulation design (block or random) has not been studied before. The aim of the study is to analyze the common and distinct parameters of affective picture perception in block and random designs by means of analysis of high frequency oscillatory dynamics (beta and gamma). EEG of 22 healthy subjects was recorded at 32 locations. The participants passively viewed 120 emotional pictures (10 x 4 unpleasant, 10 x 4 pleasant, 10 x 4 neutral) in block and random designs. The phase-locking and power of event related beta (14-28 Hz) and gamma (29-48 Hz) oscillations were analyzed for two different time windows (0-200 ms/200-400 ms). Statistical analysis showed that in the 0-200 ms time window, during the block design, unpleasant stimulation elicited higher beta phase-locking and beta power than the pleasant and neutral stimulation (p

Exploring EEG alpha oscillations has generated considerable interest, in particular with regards to the role they play in cognitive, psychomotor, psycho-emotional and physiological aspects of human life. However, there is no clearly agreed upon definition of what constitutes ‘alpha activity’ or which of the many indices should be used to characterize it. To address these issues this review attempts to delineate EEG alpha-activity, its physical, molecular and morphological nature, and examine the following indices: (1) the individual alpha peak frequency; (2) activation magnitude, as measured by alpha amplitude suppression across the individual alpha bandwidth in response to eyes opening, and (3) alpha “auto-rhythmicity” indices: which include intra-spindle amplitude variability, spindle length and steepness. Throughout, the article offers a number of suggestions regarding the mechanism(s) of alpha activity related to inter and intra-individual variability. In addition, it provides some insights into the various psychophysiological indices of alpha activity and highlights their role in optimal functioning and behavior.