Dynamic changes of ICA-derived EEG functional connectivity in the resting state.

An emerging issue in neuroscience is how to identify baseline state(s) and accompanying networks termed "resting state networks" (RSNs). Although independent component analysis (ICA) in fMRI studies has elucidated synchronous spatiotemporal patterns during cognitive tasks, less is known about the changes in EEG functional connectivity between eyes closed (EC) and eyes open (EO) states, two traditionally used baseline indices. Here we investigated healthy subjects (n = 27) in EC and EO employing a four-step analytic approach to the EEG: (1) group ICA to extract independent components (ICs), (2) standardized low-resolution tomography analysis (sLORETA) for cortical source localization of IC network nodes, followed by (3) graph theory for functional connectivity estimation of epochwise IC band-power, and (4) circumscribing IC similarity measures via hierarchical cluster analysis and multidimensional scaling (MDS). Our proof-of-concept results on alpha-band power demonstrate five statistically clustered groups with frontal, central, parietal, occipitotemporal, and occipital sources. Importantly, during EO compared with EC, graph analyses revealed two salient functional networks with frontoparietal connectivity: a more medial network with nodes in the mPFC/precuneus which overlaps with the "default-mode network" (DMN), and a more lateralized network comprising the middle frontal gyrus and inferior parietal lobule, coinciding with the "dorsal attention network" (DAN). Furthermore, a separate MDS analysis of ICs supported the emergence of a pattern of increased proximity (shared information) between frontal and parietal clusters specifically for the EO state. We propose that the disclosed component groups and their source-derived EEG functional connectivity maps may be a valuable method for elucidating direct neuronal (electrophysiological) RSNs in healthy people and those suffering from brain disorders.

A comparative randomised controlled trial of the effects of brain wave vibration training, iyengar yoga, and mindfulness on mood, well-being, and salivary cortisol.

This randomised trial compared the effects of Brain Wave Vibration (BWV) training, which involves rhythmic yoga-like meditative exercises, with Iyengar yoga and Mindfulness. Iyengar provided a contrast for the physical components and mindfulness for the "mental" components of BWV. 35 healthy adults completed 10 75-minute classes of BWV, Iyengar, or Mindfulness over five weeks. Participants were assessed at pre- and postintervention for mood, sleep, mindfulness, absorption, health, memory, and salivary cortisol. Better overall mood and vitality followed both BWV and Iyengar training, while the BWV group alone had improved depression and sleep latency. Mindfulness produced a comparatively greater increase in absorption. All interventions improved stress and mindfulness, while no changes occurred in health, memory, or salivary cortisol. In conclusion, increased well-being followed training in all three practices, increased absorption was specific to Mindfulness, while BWV was unique in its benefits to depression and sleep latency, warranting further research.

A randomised controlled single-blind trial of the efficacy of reiki at benefitting mood and well-being.

This is a constructive replication of a previous trial conducted by Bowden et al. (2010), where students who had received Reiki demonstrated greater health and mood benefits than those who received no Reiki. The current study examined impact on anxiety/depression. 40 university students-half with high depression and/or anxiety and half with low depression and/or anxiety-were randomly assigned to receive Reiki or to a non-Reiki control group. Participants experienced six 30-minute sessions over a period of two to eight weeks, where they were blind to whether noncontact Reiki was administered as their attention was absorbed in a guided relaxation. The efficacy of the intervention was assessed pre-post intervention and at five-week follow-up by self-report measures of mood, illness symptoms, and sleep. The participants with high anxiety and/or depression who received Reiki showed a progressive improvement in overall mood, which was significantly better at five-week follow-up, while no change was seen in the controls. While the Reiki group did not demonstrate the comparatively greater reduction in symptoms of illness seen in our earlier study, the findings of both studies suggest that Reiki may benefit mood.

Endogenous control of waking brain rhythms induces neuroplasticity in humans.

This study explores the possibility of noninvasively inducing long-term changes in human corticomotor excitability by means of a brain-computer interface, which enables users to exert internal control over the cortical rhythms recorded from the scalp. We demonstrate that self-regulation of electroencephalogram rhythms in quietly sitting, naive humans significantly affects the subsequent corticomotor response to transcranial magnetic stimulation, producing durable and correlated changes in neurotransmission. Specifically, we show that the intrinsic suppression of alpha cortical rhythms can in itself produce robust increases in corticospinal excitability and decreases in intracortical inhibition of up to 150%, which last for at least 20 min. Our observations may have important implications for therapies of brain disorders associated with abnormal cortical rhythms, and support the use of electroencephalogram-based neurofeedback as a noninvasive tool for establishing a causal link between rhythmic cortical activities and their functions.

Optimizing microsurgical skills with EEG neurofeedback.

BACKGROUND: By enabling individuals to self-regulate their brainwave activity in the field of optimal performance in healthy individuals, neurofeedback has been found to improve cognitive and artistic performance. Here we assessed whether two distinct EEG neurofeedback protocols could develop surgical skill, given the important role this skill plays in medicine. RESULTS: National Health Service trainee ophthalmic microsurgeons (N = 20) were randomly assigned to either Sensory Motor Rhythm-Theta (SMR) or Alpha-Theta (AT) groups, a randomized subset of which were also part of a wait-list 'no-treatment' control group (N = 8). Neurofeedback groups received eight 30-minute sessions of EEG training. Pre-post assessment included a skills lab surgical procedure with timed measures and expert ratings from video-recordings by consultant surgeons, together with state/trait anxiety self-reports. SMR training demonstrated advantages absent in the control group, with improvements in surgical skill according to 1) the expert ratings: overall technique (d = 0.6, p < 0.03) and suture task (d = 0.9, p < 0.02) (judges' intraclass correlation coefficient = 0.85); and 2) with overall time on task (d = 0.5, p = 0.02), while everyday anxiety (trait) decreased (d = 0.5, p < 0.02). Importantly the decrease in surgical task time was strongly associated with SMR EEG training changes (p < 0.01), especially with continued reduction of theta (4-7 Hz) power. AT training produced marginal improvements in technique and overall performance time, which were accompanied by a standard error indicative of large individual differences. Notwithstanding, successful within session elevation of the theta-alpha ratio correlated positively with improvements in overall technique (r = 0.64, p = 0.047). CONCLUSION: SMR-Theta neurofeedback training provided significant improvement in surgical technique whilst considerably reducing time on task by 26%. There was also evidence that AT training marginally reduced total surgery time, despite suboptimal training efficacies. Overall, the data set provides encouraging evidence of optimised learning of a complex medical specialty via neurofeedback training.

EEG applications for sport and performance.

One approach to understanding processes that underlie skilled performing has been to study electrical brain activity using electroencephalography (EEG). A notorious problem with EEG is that genuine cerebral data is often contaminated by artifacts of non-cerebral origin. Unfortunately, such artifacts tend to be exacerbated when the subject is in motion, meaning that obtaining reliable data during exercise is inherently problematic. These problems may explain the limited number of studies using EEG as a methodological tool in the sports sciences. This paper discusses how empirical studies have generally tackled the problem of movement artifact by adopting alternative paradigms which avoid recording during actual physical exertion. Moreover, the specific challenges that motion presents to obtaining reliable EEG data are discussed along with practical and computational techniques to confront these challenges. Finally, as EEG recording in sports is often underpinned by a desire to optimise performance, a brief review of EEG-biofeedback and peak performance studies is also presented. A knowledge of practical aspects of EEG recording along with the advent of new technology and increasingly sophisticated processing models offer a promising approach to minimising, if perhaps not entirely circumventing, the problem of obtaining reliable EEG data during motion.

A theory of alpha/theta neurofeedback, creative performance enhancement, long distance functional connectivity and psychological integration.

Professionally significant enhancement of music and dance performance and mood has followed training with an EEG-neurofeedback protocol which increases the ratio of theta to alpha waves using auditory feedback with eyes closed. While originally the protocol was designed to induce hypnogogia, a state historically associated with creativity, the outcome was psychological integration, while subsequent applications focusing on raising the theta-alpha ratio, reduced depression and anxiety in alcoholism and resolved post traumatic stress syndrome (PTSD). In optimal performance studies we confirmed associations with creativity in musical performance, but effects also included technique and communication. We extended efficacy to dance and social anxiety. Diversity of outcome has a counterpart in wide ranging associations between theta oscillations and behaviour in cognitive and affective neuroscience: in animals with sensory-motor activity in exploration, effort, working memory, learning, retention and REM sleep; in man with meditative concentration, reduced anxiety and sympathetic autonomic activation, as well as task demands in virtual spatial navigation, focussed and sustained attention, working and recognition memory, and having implications for synaptic plasticity and long term potentiation. Neuroanatomical circuitry involves the ascending mescencephalic-cortical arousal system, and limbic circuits subserving cognitive as well as affective/motivational functions. Working memory and meditative bliss, representing cognitive and affective domains, respectively, involve coupling between frontal and posterior cortices, exemplify a role for theta and alpha waves in mediating the interaction between distal and widely distributed connections. It is posited that this mediation in part underpins the integrational attributes of alpha-theta training in optimal performance and psychotherapy, creative associations in hypnogogia, and enhancement of technical, communication and artistic domains of performance in the arts.

Neurofeedback of SMR and Beta1 Frequencies: An Investigation of Learning Indices and Frequency-Specific Effects.

Despite evidence that Sensorimotor Rhythm (SMR) and beta1 neurofeedback have distinct cognitive enhancement effects, it remains unclear whether their amplitudes can be independently enhanced. Furthermore, demands for top-down attention control, postural restraint and maintenance of cognitive set processes, all requiring low-beta frequencies, might masquerade as learning and confound interpretation. The feasibility of selectively enhancing SMR and beta1 amplitudes was investigated with the addition of a random frequency control condition that also requires the potentially confounding cognitive processes. A comprehensive approach to assessing neurofeedback learning was undertaken through the calculation of learning indices within- and across-session and pre-to-post baseline. Herein we provide the first demonstration of beta1 within-session amplitude learning that was not attributable to extraneous cognitive processes, for it was not found with random frequency training. On the other hand, within-session SMR learning might have been obscured by high interindividual variability and methodological limitations such as the type of feedback screen, the insufficient number of sessions, and the exclusion of simultaneous theta and high-beta inhibition. Interestingly, SMR and beta1 amplitude increased across sessions in the three groups suggesting unspecific effects of neurofeedback in the low beta frequency band. Moreover, there was no clear evidence of frequency specificity associated with either SMR or beta1 training. Some methodological limitations may underpin the divergent results with previous studies.

Short-term Beneficial Effects of 12 Sessions of Neurofeedback on Avoidant Personality Accentuation in the Treatment of Alcohol Use Disorder.

This study evaluated the effects of alpha/theta neurofeedback on Clinical Personality Accentuations in individuals with alcohol use disorder. Twenty-five males were investigated using a pre-test/post-test design with a waiting-list control group. Participants were randomly assigned either to an experimental group (n = 13) receiving 12 sessions of neurofeedback twice a week as a treatment adjunct over a period of 6 weeks, or to a control group (n = 12) receiving treatment as usual. The Inventory of Clinical Personality Accentuations and the NEO-Five-Factor Inventory were applied at pre- and post-test. The neurofeedback protocol focused on enhancement of the EEG alpha (8-12 Hz) and theta (4-7 Hz) and used a visual feedback paradigm. Analyses of covariance showed improvements in Avoidant Personality Accentuation within the experimental group. Our data suggest that 12 sessions of this neurofeedback intervention might be effective in reducing avoidant and stress-related personality traits in patients with alcohol use disorder.

Event-related brain potential correlates of human auditory sensory memory-trace formation.

The event-related potential (ERP) component mismatch negativity (MMN) is a neural marker of human echoic memory. MMN is elicited by deviant sounds embedded in a stream of frequent standards, reflecting the deviation from an inferred memory trace of the standard stimulus. The strength of this memory trace is thought to be proportional to the number of repetitions of the standard tone, visible as the progressive enhancement of MMN with number of repetitions (MMN memory-trace effect). However, no direct ERP correlates of the formation of echoic memory traces are currently known. This study set out to investigate changes in ERPs to different numbers of repetitions of standards, delivered in a roving-stimulus paradigm in which the frequency of the standard stimulus changed randomly between stimulus trains. Normal healthy volunteers (n = 40) were engaged in two experimental conditions: during passive listening and while actively discriminating changes in tone frequency. As predicted, MMN increased with increasing number of standards. However, this MMN memory-trace effect was caused mainly by enhancement with stimulus repetition of a slow positive wave from 50 to 250 ms poststimulus in the standard ERP, which is termed here "repetition positivity" (RP). This RP was recorded from frontocentral electrodes when participants were passively listening to or actively discriminating changes in tone frequency. RP may represent a human ERP correlate of rapid and stimulus-specific adaptation, a candidate neuronal mechanism underlying sensory memory formation in the auditory cortex.

Validating the efficacy of neurofeedback for optimising performance.

The field of neurofeedback training has largely proceeded without validation. Here we review our studies directed at validating SMR, beta and alpha-theta protocols for improving attention, memory, mood and music and dance performance in healthy participants. Important benefits were demonstrable with cognitive and neurophysiological measures which were predicted on the basis of regression models of learning. These are initial steps in providing a much needed scientific basis to neurofeedback, but much remains to be done.

Investigating evoked and induced electroencephalogram activity in task-related alpha power increases during an internally directed attention task.

This study sought to explore whether the so-called 'paradoxical' task-related increases in the alpha bandwidth of the human electroencephalogram result from increases in evoked (phase locked), as opposed to induced (non-phase locked), activity. The electroencephalograms of 18 participants were recorded while they engaged in both auditory sensory-intake tasks (listening to randomly generated 'tunes') and internally directed attention tasks (imagining the same randomly generated tunes) matched for auditory input. Measures of evoked (phase locked) and induced (non-phase locked) activity were compared between tasks. Increases in induced alpha power were found during internal attention. No experimental effects were observed for evoked activity. These results are not entirely consistent with proposals that 'paradoxical' alpha indexes the evoked inhibition of task irrelevant processing.

Relaxation strategies and enhancement of hypnotic susceptibility: EEG neurofeedback, progressive muscle relaxation and self-hypnosis.

Hypnosis has been shown to be efficacious in a range of clinical conditions, including the management of chronic pain. However, not all individuals are able to enter a hypnotic state, thereby limiting the clinical utility of this technique. We sought to determine whether hypnotic susceptibility could be increased using three methods thought to facilitate relaxation, with particular interest in an EEG neurofeedback protocol which elevated the theta to alpha ratio. This was compared with progressive muscle relaxation and self-hypnosis. Ten subjects with moderate levels of susceptibility (2-7/12) were randomly assigned to each condition and assessed for hypnotic susceptibility prior to and upon completion of 10 sessions of training. Hypnotic susceptibility increased post-training in all groups, providing further evidence that operant control over the theta/alpha ratio is possible, but contrary to our predictions, elevation of the theta/alpha ratio proved no more successful than the other interventions. Nonetheless, all three techniques successfully enhanced hypnotic susceptibility in over half of the participants (17/30), a similar incidence to that reported using other methods. As previously reported, the majority who were not susceptible to modification were at the lower levels of susceptibility, and the greater increases tended to occur in the more susceptible subjects. However, here enhancement was disclosed in some at low levels, and capability was found of reaching high levels, both features not typically reported. Further research is warranted.

The influence of 10 min of the Johrei healing method on laboratory stress.

OBJECTIVE: Johrei has been shown to decrease exam stress responses but its immediate effects have not been assessed. DESIGN: In a randomised, blinded, counter-balanced design, 33 medical students were asked to calculate mental arithmetic in the Paced Auditory Serial Addition Task (PASAT), which served as an acute stressor prior to two conditions, 10 min of Johrei or a control resting condition involving 10 min without Johrei in a cross-over trial; after each, saliva was collected and mood tested. SETTING: University EEG laboratory. INTERVENTION: Johrei, a non-touch healing method. MAIN OUTCOME MEASURES: Profile of mood states (POMS-Bi); state anxiety (STAI); salivary variables: cortisol, DHEA, IgA. RESULTS: Mood scores on 5/6 of the POMS-Bi subscales were slightly but significantly more positive in the Johrei condition. State anxiety was similarly decreased. IgA levels were unchanged but cortisol levels were found to be slightly but non-significantly lower after Johrei than after the control condition and DHEA levels slightly but non-significantly raised, with a negative correlation between cortisol and DHEA levels. CONCLUSIONS: This study gives some indication that Johrei can reduce negative mood and increase positive mood states after the acute effects of a laboratory stressor in comparison to a resting control condition.

The Effectiveness of Visual Short-Time Neurofeedback on Brain Activity and Clinical Characteristics in Alcohol Use Disorders: Practical Issues and Results.

The present study was carried out to examine the efficacy of alpha/theta neurofeedback (NF) with a new visual paradigm in a cohort of alcohol use disordered (AUD) patients (n = 25) treated in an Austrian therapeutic community center. The experimental study design focused on changes in absolute and relative resting EEG band power as well as in clinical variables, including depression (Beck Depresion Inventory [BDI-V]), psychiatric symptoms (Brief Symptom Inventory [BSI], coping (Freiburg Questionnaire on Coping with Illness [FKV-lis]), psychotherapy motivation (Therapy Motivation Questionnaire [FPTM-23]), sense of coherence (Sense of Coherence Scale [SOC-13]), posttraumatic growth (Posttraumatic Growth Inventory [PPR]), and alcohol cravings (Alcohol Craving Questionnaire [ACQ]). For measuring training effects, participants were randomly allocated to 2 groups: an experimental group (EG, n = 13) and a control group (CG, n = 12). Patients in EG received 12 sessions of visual NF training over a period of 6 weeks to enhance alpha (8-12 Hz) and theta (4-7 Hz) frequency band power in addition to the standard treatment program of the rehabilitation center. Participants in CG received no additional NF intervention. The multivariate analysis of covariance (MANCOVA) showed a change by trend in absolute alpha and theta power in the EG. Even though no MANCOVA effects were found in the clinical scales, AUD patients reported increasing control of their brain activity during the course of NF. However, changes in several clinical scales (BDI-V, BSI, FKV-lis, PPR) from pre- to posttest were observed only in the EG contrary to the CG. The findings of this pilot study provide first evidence for the practicality and effectiveness of visual short-term NF as an additive intervention in the therapeutic community.

Psychobiology of altered states of consciousness.

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.

The effects of alpha/theta neurofeedback on personality and mood.

Alpha/theta neurofeedback has been shown to be successful both in treating addictions and in enhancing artistry in music students. How its effects are mediated are not yet clear. The present study aimed to test the hypothesis that alpha/theta neurofeedback works inter alia by normalising extreme personality and raising feelings of well being. 12 participants with high scores for Withdrawal (as measured by the PSQ) were given either alpha/theta neurofeedback or mock feedback and their personality and mood were assessed. Withdrawal scores on the PSQ-80 were not found to change in either group but significant effects were found for the Profile Of Mood States (POMS), with real feedback producing higher overall scores than mock feedback (P = 0.056). Real feedback caused participants to feel significantly more energetic (P < 0.01) than did mock feedback. Sessions of real feedback made participants feel more composed (P < 0.01), agreeable (P < 0.01), elevated (P < 0.01) and confident (P < 0.05), whilst sessions of mock feedback made participants feel more tired (P < 0.05), yet composed (P < 0.01). These findings suggest that, whilst 9 sessions of alpha/theta neurofeedback was insufficient to change personality, improvements in mood may provide a partial explanation for the efficacy of alpha/theta neurofeedback.

Changes in mismatch negativity across pre-hypnosis, hypnosis and post-hypnosis conditions distinguish high from low hypnotic susceptibility groups.

The role of alterations in mismatch negativity (MMN) in hypnosis was examined by recording MMN of the auditory ERP at frontal (F3, Fz, and F4) and mastoid (M1 and M2) placements. Frontal MMN is believed to reflect activity in right anterior cortical generators, whereas MMN at mastoid leads reflects generators located bilaterally in the temporal auditory cortex. MMN recordings were obtained in 11 low and 12 high hypnotically susceptible participants in three successive blocks; pre-hypnosis, hypnosis and post-hypnosis. Frontal (but not temporal) MMN showed a significant quadratic trend across testing conditions. It increased during hypnosis and then dropped post-hypnosis for both susceptibility groups. Linear trends for frontal and temporal MMN showed directly opposite patterns of change in the interaction between hypnotic susceptibility and testing blocks. Frontal MMN built up linearly over the test blocks in high relative to low susceptibility participants. Temporal MMN showed the reverse pattern and increased linearly across test conditions in those with low relative to high hypnotic susceptibility.

Slow habituation of induced gamma and beta oscillations in association with unreality experiences in schizotypy.

Highly schizotypal individuals exhibit deficits in attentional processing, in particular dysfunctional habituation. This has led to the suggestion that abnormal habituation may represent a trait marker of psychotic vulnerability. This study examined the difference between high- and low-schizotypal individuals' habituation of nonphase-locked gamma and beta-1 oscillations, with and without attention. Measures of schizotypy were obtained from 40 participants and habituation to different tones was examined over trials of three interval lengths, under conditions of attention and inattention. The data showed that all participants habituated over trials with long intervals when attending to the stimuli. However, those participants who scored high on the unreality subscale exhibited significantly less habituation relative to those with low unreality scores for the short-interval trials. Furthermore, there was no difference in the orienting response to the initial stimuli between these subgroups. These results are discussed in terms of a dysfunctional rehearsal process influencing habituation for those with high-unreality scores.

The influence of anxiety on electrodermal responses to distractors.

Contrary to classical expectation, anxiety has been repeatedly observed to be associated with reduced electrodermal activity. This could be the result of successful coping. In line with this interpretation, high-trait anxious individuals performing moderately arousing tasks were expected to manifest a reduced responding to distractors, since this is an adaptive outcome. High- and low-trait anxious participants had to perform a visual search task in a low-stress context. Unrelated neutral and emotional auditory words served as distractors. As a control, neutral and emotional words were also delivered in a no task condition. Skin conductance responses (SCRs) were greater during the task than during the control phase, but in the high anxious group, this increase in SCRs was smaller following emotional distractors than following neutral ones. Moreover, SCRs to both types of words habituated, but the results suggested that only the low-trait anxious participants presented the classical slowing of SCRs habituation when performing the task. All these data are interpreted as an illustration of a resource-based electrodermal inhibition in the high-trait anxious participants. It sustains the idea that mild to moderate anxiety may increase the mastery of situations.