EEG and personality differences between smokers and nonsmokers

Bilateral EEG spectra and personality were assessed in 46 habitual smokers and 46 nonsmokers, matched for age and gender. Smokers tended to have more activated EEG's than nonsmokers as indicated by higher dominant and median alpha frequencies and more fast and less slow frequency activity when relaxing with their eyes closed. Female smokers, compared to female nonsmokers, scored higher on personality trait measures of anger-proneness and psychoticism and lower on the Eysenck Personality (EPQ) conventionality/lie scale. Among males, the EPQ psychoticism scale, which has also been associated with anger, was the only personality measure found to significantly differentiate smokers from nonsmokers. The combination of EEG and personality findings is consistent with the view that there are differences between smokers and nonsmokers, such that smokers are more aroused and potentially irritated or angered more easily than nonsmokers.     

EEG alpha reactivity and extraversion-introversion

Spectral characteristics of spontaneous EEG and characteristics of the alpha attenuation response (AAR) induced by acoustic stimulation, were analyzed for two groups of subjects selected on the basis of their scores on the extraversion-introversion scale of the Eysenck Personality Questionnaire. While no significant differences were found in basic alpha rhythm, significant differences were manifested in the AAR characteristics. Extraverted subjects habituated to the auditory stimulus while introverts did not. Introverts were generally more responsive to stimulation. The results are discussed in relation to the arousability model proposed by Eysenck and Gray, verifying the relationships with typological dimensions of Superior Nervous Activity, elaborated by the Soviet school.     

Patterns of brain-electrical activity during declarative memory performance in 10-month-old infants

This study of infant declarative memory concurrently examined brain-electrical activity and deferred imitation performance in 10-month-old infants. Continuous electroencephalogram (EEG) measures were collected throughout the activity-matched baseline, encoding (modeling) and retrieval (delayed test) phases of a within-subjects deferred imitation task. Infants were divided into two memory performance groups based on the exhibition of ordered-recall after a 24-h delay. Whereas no group differences were found in EEG collected during encoding, performance-group differences in EEG were present during retrieval. Infants who successfully displayed ordered-recall showed a pattern of increasing EEG from baseline to task at anterior temporal scalp locations, whereas infants showing no ordered-recall displayed no changes in EEG from baseline to task. These findings are discussed with respect to the biobehavioral developments underlying declarative memory abilities.     

Patterns of brain-electrical activity during declarative memory performance in 10-month-old infants

This study of infant declarative memory concurrently examined brain-electrical activity and deferred imitation performance in 10-month-old infants. Continuous electroencephalogram (EEG) measures were collected throughout the activity-matched baseline, encoding (modeling) and retrieval (delayed test) phases of a within-subjects deferred imitation task. Infants were divided into two memory performance groups based on the exhibition of ordered-recall after a 24-h delay. Whereas no group differences were found in EEG collected during encoding, performance-group differences in EEG were present during retrieval. Infants who successfully displayed ordered-recall showed a pattern of increasing EEG from baseline to task at anterior temporal scalp locations, whereas infants showing no ordered-recall displayed no changes in EEG from baseline to task. These findings are discussed with respect to the biobehavioral developments underlying declarative memory abilities.     

EEG correlates of sustained attention: Hemispheric and sex differences

Subjects were presented with sets of four digits, and had to respond only when all the digits in a set were odd. The EEG was measured from occipital-parietal derivations over the left and right hemispheres, and the energy within each of five frequency bands was integrated over 3-sec epochs corresponding to the presentation of individual sets of digits. The EEG abundance was found to be lower the more a digit set resembled a signal, but hemisphere differences in this effect tended to be small and to occur only in certain frequency bands. The effect for stimulus type changed over time in some frequency bands, but there were no differences between the hemispheres in this change. Nor were sex differences in lateralization found. Reaction time was found to correlate positively with (a) EEG abundance, and (b) EEG differentiation of stimuli, in the theta and low alpha frequency bands.     

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

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

生物反馈疗法对大学生考试焦虑的治疗作用

探讨生物反馈疗法对大学生考试焦虑的治疗作用。在某大学随机抽取学生1500名,采用考试焦虑量表进行筛查,选取焦虑组和对照组各30名。利用生物反馈疗法进行干预,采用脑电α波相对功率、肌电和皮电导联进行检测,每周2次,持续4周。结果表明：1.经过4周的干预,焦虑组干预前后各生理指标存在差异;2.生物反馈疗法干预考试焦虑在疗效上存在性别差异。结论：生物反馈疗法能有效降低大学生考试焦虑水平,对其治疗取得良好的效果。     

Frontal Brain Electrical Activity in Shyness and Sociability

A number of studies have shown that shyness and sociability may be two independent personality traits that are distinguishable across a variety of measures and cultures. Utilizing recent frontal activation–emotion models as a theoretical framework, this study examined the pattern of resting frontal electroencephalographic (EEG) activity in undergraduates who self-reported high and low shyness and sociability. Analyses revealed that shyness was associated with greater relative right frontal EEG activity, whereas sociability was associated with greater relative left frontal EEG activity. Also, different combinations of shyness and sociability were distinguishable on the basis of resting frontal EEG power. Although high-shy/high-social and high-shy/low-social subjects both exhibited greater relative right frontal EEG activity, they differed significantly on EEG power in the left, but not right, frontal lead. High-shy/high-social subjects exhibited significantly less EEG power (i.e., more activity) in the left frontal lead compared with the high-shy/low-social subjects. These findings suggest that in distinguishing individual differences in personality and personality subtypes, it is important to consider not only frontal EEG asymmetry measures, but also the pattern of absolute EEG power in each frontal hemisphere.     

Emotion perception and recognition: An exploration of cultural differences and similarities

The electroencephalogram (EEG) is a powerful method for investigation of different cognitive processes. Recently, EEG analysis became very popular and important, with classification of these signals standing out as one of the mostly used methodologies. Emotion recognition is one of the most challenging tasks in EEG analysis since not much is known about the representation of different emotions in EEG signals. In addition, inducing of desired emotion is by itself difficult, since various individuals react differently to external stimuli (audio, video, etc.). In this article, we explore the task of emotion recognition from EEG signals using distance-based time-series classification techniques, involving different individuals exposed to audio stimuli. Furthermore, since some of the participants in the experiment do not understand the language of the stimuli, we also investigate the impact of language understanding on emotion perception. Using time-series distances as features for the construction of new data representations, applied here for the first time to emotion recognition and related tasks, lead to excellent classification performance, indicating that differences between EEG signals can be used to build successful models for recognition of emotions, individuals, and other related tasks. In the process, we observed that cultural differences between the subjects did not have a significant impact on the recognition tasks and models.     

Neuromarketing as a scale validation tool: Understanding individual differences based on the style of processing scale in affective judgements

This paper revisits a well-cited and widely applied consumer scale, Style of Processing (SOP) (Childers et al., Journal of Consumer Research, 1985, 12 , 125), that has been used to investigate individual differences in processing visual versus verbal information in marketing. The scale has advanced knowledge in fields related to marketing communications, product development, psychology, advertising, education and learning theories, shedding light on our understanding of consumer psychology related to persuasion, comprehension, memory, and other consumer cognitive processes involving information. In a research dialog that took place in 2008, a need for further SOP validation was suggested using a neuromarketing approach. We took this call forward and conducted an event-related-potential (ERP) experimental research study using electroencephalogram (EEG) to validate the SOP scale, focusing on differential affective processing between verbalizers and visualizers. We not only demonstrate how neuromarketing tools can be utilized to provide evidence for scale validity, providing advantages over self-reported measures; but more importantly, address issues related to understanding differential fluency effects that exist between visualizers and verbalizers. Behavioral data revealed varying reaction times to emotional stimuli of a pictorial nature. We further identify two ERP components in our data, early left anterior negativity (ELAN) and late negative slow wave (LNSW), that differentiate individual processing fluency in affective versus evaluative-based judgements. Findings confirmed the construct validity of the SOP scale and enhance our understanding of individual differences in emotional processing of pictorial information.     

Fourier analyses: A mathematical and geometric explanation

Fourier analyses are used in electrophysiological research to reduce EEG data to an interpretable, analyzable form. This article outlines the mathematical similarities and differences between Fourier transforms and fast Fourier transforms. A geometric explanation of the application of fast Fourier transforms and a Fourier series to theta-band EEG data is also included in this article.     

EEG correlates of behavioural laterality: right-handedness

Among right-handers, the magnitude of differences in proficiency between the left and right hands varies considerably. Yet significance of the extent of right-handedness is still a controversial issue. To examine whether individual differences in asymmetry of hand skill can partly be attributed to individual differences in asymmetrical hemispheric activation, handedness and electroencephalographic (EEG) laterality were correlated in two large samples (ns = 60 and 128). Analysis indicated that part of the variability in right-handedness may arise from activation asymmetries in the cortex, but whether this relation becomes apparent depends on the cortical area examined and on the experimental condition under which the EEG measures are taken.     

Cognition and affective style: Individual differences in brain electrical activity during spatial and verbal tasks

Relations between brain electrical activity and performance on two cognitive tasks were examined in a normal population selected to be high on self-reported measures of Positive or Negative Affectivity. Twenty-five right-handed women, from an original pool of 308 college undergraduates, were the participants. EEG was recorded during baseline and during psychometrically matched spatial and verbal tasks. As predicted, participants who were high in Positive Affectivity performed equally well on the verbal and spatial tasks, while participants who were high in Negative Affectivity had spatial scores that were lower than their verbal scores. There were no group differences in baseline EEG. Both groups exhibited left central activation (i.e., alpha suppression) during the verbal and spatial tasks. When EEG data were analyzed separately for the group high in Positive Affectivity, there was evidence of parietal activation for the spatial task relative to the verbal task. The EEG data for the group high in Negative Affectivity had comparable EEG power values during verbal and spatial tasks at parietal scalp locations. These data suggest that, within a selected normal population, differences in affective style may interact with cognitive performance and with the brain electrical activity associated with that performance.     

Psychological defense mechanisms and electroencephalographic arousal

The aim of this study was to examine the relationship between psychological defense as measured by the Kragh tachistoscopic Defense Mechanisms Test (DMT), and general arousal properties of the individual as measured with electroencephalogram (EEG). The DMT assesses defense by presenting neutral and threatening pictures with very short exposure times. EEG characteristics were measured in the 8–12 Hz EEG frequency band during DMT testing. Twenty-one male subjects participated in the study. All were US Air Force personnel on active duty. Personnel with high defense mechanisms, defined in this connection as slow perception of the threat, tended to have higher cortical arousal after Stimulus exposure than the subjects with low defense mechanisms. The differences occurred mainly with new stimulus material without any threatening content. The differences in arousal response to novel stimuli may contribute to an understanding of the relationships between the Kragh DMT test and performance in life-threatening situations.     

Electroencephalographic correlations of temporally spaced responding and avoidance behavior

This study was undertaken to determine whether any EEG changes occurred during a multiple schedule of reinforcement consisting of repeated periods of avoidance behavior, a time-out (TO) period, and a period of differential reinforcement of low rates (DRL). The two monkeys were permanently implanted with bipolar electrodes in various subcortical areas. The EEG was recorded from these electrodes for several weeks before any behavioral training was undertaken. Training was then begun in the multiple schedule, and EEG recordings were taken frequently throughout the training period. When a stable performance level was achieved, drugs (dl-amphetamine and sodium pentobarbital) were introduced which disrupted the DRL performance but had little or no effect on avoidance behavior. The EEG recordings continued throughout these drug studies.

The data indicate that the marked behavioral differences noted in each component of the schedule were not reflected in the EEG. However, the EEG did correlate with the general level of alertness of the animals during the various components. The drugs which differentially affected the behavior in the components of the schedule did not differentially affect the EEG, but they did change the brain-wave activity equally in all components. Finally, EEG changes correlated with the complex motor response of lever pressing were not observed.

     

Differences in EEG alpha activity related to giftedness

In three experiments, differences in EEG alpha activity between gifted (mean IQ = 137) and average (mean IQ = 105) individuals were investigated. EEG activity was monitored over 16 scalp locations. A fast Fourier transform was performed on 15 artifact-free 2-second chunks of data to derive a spectral power average in the alpha band (7.5–13 Hz). In the first experiment, EEG of gifted and average individuals during two relaxation phases—eyes closed and eyes open—was recorded. Gifted individuals showed higher EEG alpha power only while resting with eyes open. In the second experiment, gifted and average individuals solved two problems that were divided into phases of problem solving and preparing for problem solving (reading, making a plan of how to solve the problem). Significant differences were obtained only for the problem-solving stages. Gifted individuals in comparison with average ones showed higher alpha power (less mental effort) while solving the two problems. The third experiment investigated whether the lower mental activity displayed by gifted individuals was related to their ability to form more abstract schemata. For that purpose EEG was recorded while gifted and average individuals memorized lists of words and pictures that either allowed, or did not allow, for classification into more abstract categories. For both types of lists, gifted individuals displayed higher alpha power than average ones. The results obtained confirm the hypothesis that the higher EEG alpha power during information processing displayed by gifted individuals may derive from the nonuse of many brain areas not required for the problem at hand.     

Contribution of the speech musculature to apparent human EEG asymmetries prior to vocalization

Vocalizations are preceded by slow EEG waves over inferior frontal scalp regions, but some controversy exists as to whether these slow potentials are left-lateralized as a function of speech. In this study both speech and non-speech vocalizations were studied, under conditions of repetitive and variable production. Averaged responses over the speech musculature, including the temporalis, masseter, orbicularis oris, and mylohyoid muscles, as well as the eyes and tongue, were calculated simultaneously with scalp EEG averages. The responses of the temporalis and masseter muscles, as well as that of the tongue, were correlated with EEG sites at specific latencies prior to speech, suggesting that no part of the inferior frontal EEG record was free from myogenic confounds. In addition, all significant EEG differences between speech and non-speech conditions were subsequently eliminated by covariance analysis, using selected muscle channels as covariates. Previous reports of asymmetrical “speech potentials” in the EEG probably reflected a combination of several myogenic confounds.     

The EEG and intelligence: An appraisal of methods and theories

Formerly, attempts were made to discover some relationship between intelligence differences and measures of “spontaneous” EEG activity. More recently the focus of interest has shifted to a putative relationship between intelligence differences and differences in EEG responses evoked by sensory stimulation. This article identifies serious conceptual and methodological problems of the EEG-intelligence literature which render some EEG-intelligence theories untenable. It is concluded that the “cerebral arousability” theory of EEG-intelligence relations is the only one that can account for the physical, neurological and psychological facts while addressing the main issues that have dominated the whole field of intelligence research for the past 100 years.     

Cognitive task effects on hemispheric blood flow in humans: Evidence for individual differences in hemispheric activation

Evidence from two indirect measures of hemispheric activity, EEG α and conjugate lateral eye movements, has pointed to the existence of individual differences in hemispheric activation. Results from a more direct indicator of hemispheric activity, regional cerebral blood flow as measured by the ¹³³Xe inhalation method, show that such individual differences can be detected in the distribution of blood in the two hemispheres and that the amount of increase in blood flow in the right relative to the left hemisphere is correlated with performance on a spatial task. These results corroborate and extend the findings from the EEG and eye movement studies and suggest that the dimension of individual differences in hemispheric activation may exert significant influence on cognitive performance and on problem-solving strategies.     

Maturation of EEG power spectra in early adolescence: a longitudinal study

This study investigated the fine-grained development of the EEG power spectra in early adolescence, and the extent to which it is reflected in changes in peak frequency. It also sought to determine whether sex differences in the EEG power spectra reflect differential patterns of maturation. A group of 56 adolescents were tested at age 10 years and then at two further time-points approximately 18 months apart. The EEG was recorded during both eyes-closed and eyes-open conditions and Fourier transformed to provide estimates of absolute and relative spectral power at 0.5 Hz intervals from 0.5 to 40 Hz. The peak alpha frequency for each individual at each time-point was also determined for relative spectral power. Partial Least Squares (PLS) analysis was used to determine the combination of electrodes and frequencies that showed developmental change, or differed between the sexes. As a function of age, absolute delta and theta frequencies power decreased, and relative alpha2 and beta frequencies increased, replicating the standard findings of a decrease in lower, and increase in higher, frequencies with age. A small but significant increase in peak alpha frequency with age was detected. Moreover PLS analysis performed with individual alpha frequencies aligned to 10 Hz suggested that the age-related increase seen in alpha2 relative power was driven by changes in the peak frequency. Although males demonstrated higher alpha power than females, there were no sex differences in peak frequency, suggesting that there may be more to sex differences in EEG power than simply different rates of maturation between the two sexes.