EEG Power Changes Research Articles

Ankle Robotics Training in Sub-Acute Stroke Survivors: Concurrent within-Session Changes in Ankle Motor Control and Brain Electrical Activity (P01.175)

Objective: The goal of this pilot study was to assess whether a single session of ankle robot (anklebot) training would improve paretic ankle motor control with concurrent changes in brain electrical activity in sub-acute stroke survivors. Background Nearly 800,000 new cases of stroke are reported each year according to the American Heart Association, making it the leading cause of serious, long-term disability in the U.S. For many stroke survivors, hemiparetic gait and balance dysfunction are ongoing issues that limit mobility and increase energy demands for performing the activities of daily living. The ankle is a prime target for intervention because of the crucial role it plays in forward propulsion, shock absorption, and dynamic balance during locomotion. Design/Methods: Two subjects, who presented with subcortical lesions, performed ankle targeting movements in plantar/dorsiflexion and inversion/eversion ranges with robotic assistance needed, while 64 channels of EEG were collected. Results: Both subjects improved their paretic ankle motor control as indexed by increased targeting accuracy, faster speed and smoother movements. These changes were accompanied by concomitant decreases in gamma power within the motor planning region in the hemisphere contra-lateral to the paretic ankle. In addition, increased networking (beta coherence) between motor planning and visuo-spatial regions was observed in both subjects. Conclusions: The results of this study suggest that a single session of anklebot training leads to short-term gains in motor control at the hemiparetic ankle that are accompanied by changes in EEG power and coherence. Increases in task relevant and regionally specific coherence have been associated with the early stages of learning. The ability to correlate single session improvements in ankle motor control with concurrent changes in brain electrical activity will allow for the development of more efficacious anklebot training interventions that may translate to gains in gait function during the early stages of stroke. Supported by: American Academy of Neurology. Disclosure: Dr. McGehrin has nothing to disclose. Dr. Roy has nothing to disclose. Dr. Goodman has nothing to disclose. Dr. Rietschel has nothing to disclose. Dr. Forrester has nothing to disclose. Dr. Bever has nothing to disclose.

Anticonvulsant effect of Marsilea quadrifolia Linn. on pentylenetetrazole induced seizure: A behavioral and EEG study in rats

Ethnopharmacological relevanceMarsilea quadrifolia Linn (MQ) extract has been used traditionally as sedative and antiepileptic drug in India. Aim of this studyTo investigate the anticonvulsive potential of MQ extracts by using behavior and electroencephalographic (EEG) analysis on pentylenetetrazole (PTZ) induced seizure model in rats. Materials and methodsFor anticonvulsant effect, 60minutes after administration of MQ, behavior and EEG were analyzed during PTZ (60mg/kg) induced seizures. Changes of EEG power, latency of onset of seizure, seizure severity score, and duration of epileptic seizure were determined. ResultsBoth the water and ethanol extract of MQ increased the latency of seizure but also decreased duration of epileptic seizure and seizure severity score. This reduction of seizure severity was also observed in EEG recording and EEG power analysis. The effectiveness of MQ ethanol extract is better than MQ water extract. ConclusionBoth water and ethanol extract of MQ were effective in reducing the severity of behavioral and EEG seizures induced by PTZ in rats. This study justifies the traditional use of this plant in epilepsy.

A frequency band analysis of two-year-olds’ memory processes

Research on the functional meaning of EEG frequency bands during memory processing has only examined two developmental periods: infancy and from late childhood to adulthood. The purpose of this study was to examine changes in EEG power for three toddler EEG frequency bands (3–5Hz, 6–9Hz, 10–12Hz) during a verbal recall task. To this end, we asked three questions: (a) Which frequency band(s) discriminate baseline from memory processing?; (b) Which frequency band(s) differentiate between memory encoding and retrieval processes?; (c) Which frequency band(s) distinguish toddlers with high and low verbal recall performance? Analysis of 2-year-olds’ (n=79) power values revealed that all three frequency bands differentiated the retrieval and encoding phases from the baseline phase; however, the particular regions that exhibited this dissociation varied. Retrieval-related increases in 3–5Hz (theta) power were widespread. Only the 3–5Hz and 6–9Hz bands distinguished encoding and retrieval processes; retrieval power values were higher than encoding power values. High and low verbal recall performers were discriminated by all frequency bands; high performers had greater power values than low performers. Thus, the 3–5Hz (theta) and 6–9Hz (alpha) bands were most informative about 2-year-olds’ memory processes. Theta and alpha rhythms are critical to memory processes during late childhood and adulthood, and our findings provide initial evidence that these rhythms are also intricately linked to memory processing during toddlerhood. These findings are discussed in relation to behavioral changes in memory processes.

EEG-power and -coherence changes in a unimodal and a crossmodal working memory task with visual and kinesthetic stimuli

We investigated EEG-power and EEG-coherence changes in a unimodal and a crossmodal matching-to-sample working memory task with either visual or kinesthetic stimuli. Angle-shaped trajectories were used as stimuli presented either as a moving dot on a screen or as a passive movement of a haptic device. Effects were evaluated during the different phases of encoding, maintenance, and recognition. Alpha power was modulated during encoding by the stimulus modality, and in crossmodal conditions during encoding and maintenance by the expected modality of the upcoming test stimulus. These power modulations were observed over modality-specific cortex regions. Systematic changes of coherence for crossmodal compared to unimodal tasks were not observed during encoding and maintenance but only during recognition. There, coherence in the theta-band increased between electrode sites over left central and occipital cortex areas in the crossmodal compared to the unimodal conditions. The results underline the importance of modality-specific representations and processes in unimodal and crossmodal working memory tasks. Crossmodal recognition of visually and kinesthetically presented object features seems to be related to a direct interaction of somatosensory/motor and visual cortex regions by means of long-range synchronization in the theta-band and such interactions seem to take place at the beginning of the recognition phase, i.e. when crossmodal transfer is actually necessary.

Electroencephalogram bands modulated by vigilance states in an anuran species: a factor analytic approach

Dramatic changes in neocortical electroencephalogram (EEG) rhythms are associated with the sleep-waking cycle in mammals. Although amphibians are thought to lack a neocortical homologue, changes in rest-activity states occur in these species. In the present study, EEG signals were recorded from the surface of the cerebral hemispheres and midbrain on both sides of the brain in an anuran species, Babina daunchina, using electrodes contacting the meninges in order to measure changes in mean EEG power across behavioral states. Functionally relevant frequency bands were identified using factor analysis. The results indicate that: (1) EEG power was concentrated in four frequency bands during the awake or active state and in three frequency bands during rest; (2) EEG bands in frogs differed substantially from humans, especially in the fast frequency band; (3) bursts similar to mammalian sleep spindles, which occur in non-rapid eye movement mammalian sleep, were observed when frogs were at rest suggesting sleep spindle-like EEG activity appeared prior to the evolution of mammals.

EEG and ECG from 5 to 10 months of age: Developmental changes in baseline activation and cognitive processing during a working memory task

We recorded electroencephalogram (EEG) and electrocardiogram (ECG) from 20 infants monthly between 5 and 10 months of age during baseline and during performance on the looking A-not-B task of infant working memory. Analyses of baseline data showed age-related increases in EEG power (medial frontal, central, temporal, medial parietal, lateral parietal, and occipital electrode sites) and coherence (frontal pole–medial frontal, medial frontal–lateral frontal, medial frontal–medial parietal, and medial frontal–occipital electrode pairs), and decreases in heart rate (HR). Patterns of age-related change were similar for EEG power, EEG coherence, and HR. Analyses of task data relative to baseline revealed task-related increases in EEG power (all electrode sites), but no task-related changes in EEG coherence (medial frontal pairings) and HR. There was some evidence of localized task-related changes in EEG power by 10 months of age. These data highlight age-related changes in EEG and ECG, as well as the functional significance of these psychophysiological measures during baseline and during cognitive processing in the first year.

EEG power changes reflect distinct mechanisms during long‐term memory retrieval

The roles of theta and alpha oscillations for long-term memory (LTM) retrieval are still under debate. Both are modulated by LTM retrieval demands, but it is unclear what specific LTM functions they are related to. Here, different oscillatory correlates of LTM retrieval could be obtained for theta and alpha with a paradigm that is suited to monitor the activation of a varying number of material-specific LTM representations. Both frequency bands responded parametrically to the number of retrieved items. However, only the alpha effect dissociated topographically for material type, indicating that the activation of material-specific representations became systematically modulated. For theta, this effect was material-unspecific with mid-frontal topography. These results suggest that alpha is functionally related to the activation of stored information, whereas theta is a sign of retrieval-related control processes.

Effects of unstructured video exposure on EEG power in situations of forced attention and rest

Group 1 (N = 30) and group 2 (N = 22) of healthy volunteers participated in the experiment. EEG registration took place while the examinees were in the resting states: with closed eyes; with opened eyes; with opened eyes and being under exposure to TV channel noises (white noise). Group 1 had also to fulfill a task to count randomly appearing symbols on a screen and group 2 had to fulfill a task to find an image in the noises. Averaged values of EEG power in each of the derivations in each of the derivations were calculated for an every examinee and for each of the states. The estimations were done in delta, theta, alpha1, alpha2, beta1, beta2, gamma frequency bands. The received results demonstrate that exposure to unstructured non-informative video noise can lead to significant changes of EEG power in a variety of frequency bands which are most prominent in the band alpha2. The changes are topically widespread, reflecting systemic changes in corresponding brain mechanisms, but are much less intensive if compared to changes between resting states with opened and closed eyes.

EEG, Activity, and Sleep Architecture in a Transgenic AβPPswe/PSEN1A246E Alzheimer's Disease Mouse

Since sleep and electroencephalogram (EEG) disturbances are endophenotypes of Alzheimer's disease (AD) patients alongside cognitive dysfunction, we here characterized these parameters in transgenic mice carrying transgenes for amyloid-β protein precursor (AβPPswe) and presenilin 1 (PSEN1A246E) at 5 (pre-plaque) and 20 months, relative to PSEN1 and wild-type (WT) mice, using a novel wireless microchip device. While circadian rhythms were not affected, we obtained significantly higher overall activity at 5 months in the AβPP/PSEN1 strain (p < 0.001) compared to both PSEN1 and WT animals. Vigilance staging revealed that AβPP/PSEN1 animals present with an age-independent increase in wakefulness (p < 0.001) and a decrease in non rapid-eye movement (NREM) sleep (p < 0.01). These changes were age- and genotype-dependent only during the light phase, while dark phase activity pattern were equally affected at both ages. In all genotypes, the amount of REM sleep was lower at 20 months indicating a general age-related profile. Spectral power of qEEG changed in AβPP/PSEN1 mice at 5 months during wakefulness and REM sleep; during wakefulness hippocampal delta (0.5-5 Hz) was reduced and theta (5-9 Hz) power enhanced. By contrast, NREM EEG spectra were affected by age and genotype. Interestingly, PSEN1 animals also showed spectral EEG changes, these differed from both WT and AβPP/PSEN1 animals. Our results indicate that AβPP/PSEN1 mice exhibit abnormalities in activity and sleep architecture preceding amyloid plaque deposition as well as age-related changes in cortical EEG power. Though not fully recapitulating the profile of AD patients, this suggests activity and EEG recordings as sensitive and translational biomarkers in murine models.

Sleep deprivation suppresses the increase of rapid eye movement density across sleep cycles

We investigated the association between rapid eye movement (REM) density (REMd) and electroencephalogram (EEG) activity during non-rapid eye movement (NREM) and REM sleep, within the re-assessment, in a large sample of normal subjects, of the reduction of oculomotor activity in REM sleep after total sleep deprivation (SD). Coherently with the hypothesis of a role of homeostatic sleep pressure in influencing REMd, a negative correlation between changes in REMd and slow-wave activity (SWA) was expected. A further aim of the study was to evaluate if the decreased REMd after SD affects ultradian changes across sleep periods. Fifty normal subjects (29 male and 21 female; mean age=24.3 ± 2.2 years) were studied for four consecutive days and nights. Sleep recordings were scheduled in the first (adaptation), second (baseline) and fourth night (recovery). After awakening from baseline sleep, a protocol of 40 h SD started at 10:00 hours. Polysomnographic measures, REMd and quantitative EEG activity during NREM and REM sleep of baseline and recovery nights were compared. We found a clear reduction of REMd in the recovery after SD, due to the lack of REMd changes across cycles. Oculomotor changes positively correlated with a decreased power in a specific range of fast sigma activity (14.75-15.25 Hz) in NREM, but not with SWA. REMd changes were also related to EEG power in the 12.75-13.00 Hz range in REM sleep. The present results confirm the oculomotor depression after SD, clarifying that it is explained by the lack of changes in REMd across sleep cycles. The depression of REMd can not simply be related to homeostatic mechanisms, as REMd changes were associated with EEG power changes in a specific range of spindle frequency activity, but not with SWA.

The effect of acute effort on EEG in healthy young and elderly subjects

The effects of physical exercise on mental health have been extensively investigated, mainly in older people. Recent studies have looked into the acute effect of exercise on the brain using standardized low-resolution brain electromagnetic tomography (sLORETA). We assessed EEG power and mood changes after 20min of aerobic exercise in elderly (N=10) and young (N=19) healthy individuals. Both groups showed improvement in total mood disturbance (TMD) post exercise (young: P=0.03; elderly: P=0.02). Only the young group showed significant improvement in anger (P=0.05) and vigor (P=0.006). Comparison pre versus post-exercise for each group separately revealed significant changes in the young group (an increase in alpha, beta-1 and beta-2 activity in Brodmann areas 24, 33 and 23, respectively). However, the elderly group did not show significant changes. An inverse correlation was found between alpha asymmetry and STAI (rs=-0.50; P=0.029) in the young group. On the other hand, a significant correlation between beta-1 activity and TMD was observed in the elderly group (rs=0.67; P=0.045). We conclude that acute exercise can have distinct effects on brain activity and mood variables in young individuals when compared with elderly adults. However, additional studies are necessary to further investigate the role of exercise intensity in these results.

EEG Delta Power Decline Can Begin Before Age 11: A Reply to Campbell and Feinberg

CAMPBELL AND FEINBERG1 QUESTION OUR CONCLUSION THAT THE ADOLESCENT SLEEP EEG POWER DECLINE CAN OCCUR BEFORE AGE 11 YEARS BY presenting averaged data from children whose sleep was studied on unspecified “usual” schedules. They state that delta power decline begins after age 11 and hypothesize that this age “…signals the onset of brain adolescence” characterized by “…massive, parallel declines in cerebral metabolic rate, synaptic density and delta wave amplitude.”1 Findings from neuroanatomical studies suggest that defining the onset of cortical reorganization in the healthy maturing brain is not so straightforward. By stating that this process does not begin until after age 11, Campbell and Feinberg overlook such important factors as (1) brain maturation occurs at different times in different cortical regions and (2) the timing of maturation is associated with significant individual variability (in part related to sex2). Studies using MRI,2,3 postmortem synaptic density,4 waking EEG,5 and PET6 indicate developmental differences among brain regions. For example, an MRI study showed peak cortical thickness at different ages in different regions3; a corollary is that the age-related decline began at different ages for different regions. Decline in gray matter volume is thought to reflect the elimination of synapses, seen as reduced EEG amplitude.5 Furthermore, Feinberg et al.7 have modeled the maturational curves for delta wave amplitude in the sleep EEG showing the age of peak delta wave amplitude at 7.4 years. The recent Campbell and Feinberg8 data derive from a single EEG derivation C3/A2 or C4/A1 (used interchangeably), which lies over the postcentral gyrus.9 Shaw et al.3 estimated 8.5 years as the age of peak cortical thickness in this region. Our data,10 collected under conditions where prior sleep and in-lab time in bed were held constant, support the notion that the sleep EEG can manifest cortical maturation at an early age. For example, we found a 55% reduction in delta power and a 52% decline in overall power (PΔ of −44%/year, Figure 1)10 at C3/A2 for one boy from age 9.4 to 11.2 years. Furthermore, the decline in sleep EEG power occurred for frequencies up to 16 Hz (Figure 4).10 Our data also showed that the sleep EEG power changes differed regionally (see Figures 2 and 4).10 Our findings show that the maturational timing varies, cannot be pinpointed to a specific age, and can begin before age 11. The individual variability shown in Figure 1 and Table 110 emphasizes this point. Indeed, large individual differences appear in Campbell and Feinberg's8 Figure 2, where several participants show decreases of delta power before age 11 and others large increases in delta power after age 11. We conclude by congratulating Campbell and Feinberg on their longitudinal studies and Feinberg for his pioneering work. Our comments were meant to highlight methodological differences in control of such variables as prior sleep and sleeping environment that impact the sleep EEG and may account for the observed differences. Finally, neither our data set nor that of Campbell and Feinberg8 can provide a definitive statement about the onset of “brain adolescence” without including younger children in whom synaptic pruning has not yet begun.

Electroencephalographic responses to tail clamping in anaesthetized rat pups

We investigated electroencephalographic (EEG) responses to tail clamping in lightly anaesthetized rat pups (5-22 days) in order to determine the ontogeny of EEG activity and at what age they may be capable of experiencing pain. Median frequency (F50) and spectral edge frequency (F95) of the power spectrum in the range of 1-30 Hz were determined before and after the application of a noxious stimulus and power spectra were compared by multivariate analysis. There was a postnatal increase in EEG power as, before clamping, pups aged 5-7 days exhibited isoelectric traces, whereas those aged 12-14 days and 21-22 days had intermittent EEG activity where the power in all frequencies was significantly lower at the former than at the latter age. Pups aged 5-7 days exhibited no EEG response to clamping in view of their isoelectric traces. Pups aged 12-14 days showed a significant decrease in F95 (P=0.002), whereas those aged 21-22 days showed highly significant reduction in F50 and F95 (P=0.028 and P<0.001, respectively) as well as changes in EEG power of specific frequencies after clamping. The results and related literature suggest that rat pups aged 5-7 days and younger are not likely to perceive pain and that the ability to perceive pain develops gradually between postnatal ages 12-14 days and 21-22 days.

Post-movement beta synchronisation after complex prosaccade task

Objective Post-movement beta synchronisation (PMBS) has been described as an induced, localised increase of beta activity over the contralateral sensorimotor cortex after termination of voluntary limb movement. The aim of our study was to investigate whether ocular saccades also evoke movement related EEG changes. Methods Complex saccades were recorded in six healthy volunteers using electro-oculography. EEG power changes in the beta frequency band were measured before, during and after saccades. Results Significant increase of beta-power was observed over the frontocentral region of both hemispheres after the offset of the complex saccade task. The latency of ocular PMBS was about 1100 ms. Conclusions Ocular PMBS evoked by complex saccade task is similar to that of recorded after limb movements. Its presence over both hemispheres irrespective of the direction of saccades indicates bilateral activation of cortical areas connected with the execution and planning of ocular movements. Significance The present paper is the first report on eye-movement related post-movement beta synchronisation. Investigation of ocular PMBS can be used both for research and clinical purposes for the functional assessment of neuronal networks controlling eye movements.

EEG activity in Carmelite nuns during a mystical experience

Mystical experiences relate to a fundamental dimension of human existence. These experiences, which are characterized by a sense of union with God, are commonly reported across all cultures. To date, no electroencephalography (EEG) study has been conducted to identify the neuroelectrical correlates of such experiences. The main objective of this study was to measure EEG spectral power and coherence in 14 Carmelite nuns during a mystical experience. EEG activity was recorded from 19 scalp locations during a resting state, a control condition and a mystical condition. In the mystical condition compared to control condition, electrode sites showed greater theta power at F3, C3, P3, Fz, Cz and Pz, and greater gamma1 power was detected at T4 and P4. Higher delta/beta ratio, theta/alpha ratio and theta/beta ratio were found for several electrode sites. In addition, FP1-C3 pair of electrodes displayed greater coherence for theta band while F4-P4, F4-T6, F8-T6 and C4-P4 pairs of electrodes showed greater coherence for alpha band. These results indicate that mystical experiences are mediated by marked changes in EEG power and coherence. These changes implicate several cortical areas of the brain in both hemispheres.

Changes in the power and coherence spectra of the EEG rhythmic components during solution of a verbal creative task of overcoming a stereotype

Changes in EEG power and coherence were analyzed in 117 subjects during the performance of the creative task of finishing well-known proverbs in a new way, so as to change, if possible, their meaning, and the noncreative task of recalling the original (well-known) version of the end of each proverb. A characteristic feature of the creative task was that proverbs and sayings are stereotypes fixed in a memory matrix. During the task performance, the EEG was recorded in 19 derivations according to the international 10–20 system. Performance of the creative task was accompanied by a highly significant and reproducible increase in the power of the γ and β2 EEG frequency bands, as well as a less pronounced decrease in the power of the ϑ band in the central and parietoccipital cortical areas. In addition, the performance of the creative task was also characterized by an increase in the EEG coherence in the α2, β2, and γ bands. No gender-related differences were found in the patterns of EEG changes.

Effects of concurrent visual tasks on cortico-muscular synchronization in humans

To study the effects of external visual stimulation on motor cortex-muscle synchronization, coherence between electroencephalography (EEG) and electromyography (EMG) was measured in normal subjects under Before, Task (visual task: Ignore or Count, or arithmetic task) and After conditions. The control (Before and After) conditions required the subject to maintain first dorsal interosseous muscle contraction without visual stimulation. In the visual task, a random series of visual stimuli were displayed on a screen while the subjects maintained the muscle contraction. The subjects were asked to ignore the stimuli in the Ignore condition and to count certain stimuli in the Count condition. Also, in the arithmetic task, the subjects were asked to perform a simple subtraction. The EEG–EMG coherence found at C3 site at 13–30 Hz (beta) was increased and sustained in magnitude during the Ignore and Count conditions, respectively. To examine the cause of the change of coherence, changes of EEG and EMG spectral power were computed for each frequency band. There was little change in the EMG spectral power in any frequency bands. While the spectral power of EEG unchanged in the beta band, it significantly increased and decreased in the range of 8–12 Hz and of 31–50 Hz, respectively, for both Ignore and Count conditions, not only at the C3 site but at various sites as well. These results were in contrast to those obtained for the arithmetic task: the beta band EEG–EMG coherence was attenuated and the EEG spectral power at 4–7 Hz and at 31–50 Hz were significantly increased and decreased, respectively. As a conclusion, the present results are consistent with the idea that the enhanced 8–12 Hz/decreased 31–50 Hz oscillations affect strength of the beta band cortico-muscular synchronization by suppressing the visual processing.

Neural correlates of regional EEG power change

To clarify the physiological significance of task-related change of the regional electroencephalogram (EEG) rhythm, we quantitatively evaluated the correlation between regional cerebral blood flow (rCBF) and EEG power. Eight subjects underwent H 2 15O positron emission tomography scans simultaneously with EEG recording during the following tasks: rest condition with eyes closed and open, self-paced movements of the right and left thumb and right ankle. EEG signals were recorded from the occipital and bilateral sensorimotor areas. Cortical activation associated with EEG rhythm generation was studied by the correlation between rCBF and EEG power. There were significant negative correlations between the sensorimotor EEG rhythm at 10–20 Hz on each side and the ipsilateral sensorimotor rCBF and between the occipital EEG rhythm at 10–20 Hz and the occipital rCBF. The occipital EEG rhythm showed a positive correlation with the bilateral medial prefrontal rCBF, while the right sensorimotor EEG rhythm showed a positive correlation with the left prefrontal rCBF. In conclusion, decrease in the regional EEG rhythm at 10–20 Hz might represent the neuronal activation of the cortex underlying the electrodes, at least for the visual and sensorimotor areas. The neural network including the prefrontal cortex could play an important role to generate the EEG rhythm.

Changes in Brain Functioning From Infancy to Early Childhood: Evidence From EEG Power and Coherence During Working Memory Tasks

Using measures of EEG power and coherence with a longitudinal sample, the goal of this study was to examine developmental changes in brain electrical activity during higher order cognitive processing at infancy and early childhood. Infants were recruited at 8 months of age and performed an infant working-memory task based on a looking version of the A-not-B task. At age 4.5 years, one half of the original sample returned for a follow-up visit and were assessed with age-appropriate working-memory tasks. At infancy, working memory was associated with changes in EEG power from baseline to task across the entire scalp, whereas in early childhood, working memory was associated with changes in EEG power from baseline to task at medial frontal only. Similar results were found for the EEG coherence data. At infancy, working memory was associated with changes in EEG coherence from baseline to task across all electrode pairs and by 4.5 years of age, EEG coherence changed from baseline to working-memory task at the medial frontal/posterior temporal pairs and the medial frontal/occipital pairs. These EEG power and coherence longitudinal data suggest that brain electrical activity is widespread during infant cognitive processing and that it becomes more localized during early childhood. These findings may yield insight into qualitative changes in cortical functioning from the infant to the early childhood time periods, adjustments that may be indicative of developmental changes in brain specialization for higher order processes.

Changes in the power and coherence of the β2 EEG band in subjects performing creative tasks using emotionally significant and emotionally neutral words

Changes in the power and coherence of the β2 EEG band (18.5–30 Hz) were studied in subjects performing creative tasks under the conditions of emotional induction of different valence and without it. EEGs were recorded in subjects instructed to think up, within a limited time, the largest possible number of original definitions, differing in meaning, of emotionally positive, negative, and neutral nouns using additional words that were selected for them from another or the same semantic field. Significant changes in EEG power and coherence were found in the β2 band. The performance of the creative task without emotional induction led to a local decrease in β2 EEG power in the left frontotemporal area and a diffuse decrease in the coherence of the same band in most cortical zones. Emotional induction had a considerably stronger effect on the state of the cortex than the creative tasks used in the study: positive emotional induction caused a generalized increase in the power and coherence of the β2 EEG band, while negative emotional induction caused a diffuse decrease in the power of this band over the parietal, central, and temporal cortical areas.