Neuroelectric Correlates of Human Sexuality: A Review and Meta-Analysis

Many reviews on sexual arousal in humans focus on different brain imaging methods and behavioral observations. Although neurotransmission in the brain is mainly performed through electrochemical signals, there are no systematic reviews of the electrophysiological correlates of sexual arousal. We performed a systematic search on this subject and reviewed 255 studies including various electrophysiological methods. Our results show how neuroelectric signals have been used to investigate genital somatotopy as well as basic genital physiology during sexual arousal and how cortical electric signals have been recorded during orgasm. Moreover, experiments on the interactions of cognition and sexual arousal in healthy subjects and in individuals with abnormal sexual preferences were analyzed as well as case studies on sexual disturbances associated with diseases of the nervous system. In addition, 25 studies focusing on brain potentials during the interaction of cognition and sexual arousal were eligible for meta-analysis. The results showed significant effect sizes for specific brain potentials during sexual stimulation (P3: Cohen's d = 1.82, N = 300, LPP: Cohen's d = 2.30, N = 510) with high heterogeneity between the combined studies. Taken together, our review shows how neuroelectric methods can consistently differentiate sexual arousal from other emotional states.

Auditory Processing of the Brain Is Enhanced by Parental Singing for Preterm Infants

As the human auditory system is highly malleable in infancy, perinatal risk factors, such as preterm birth, may affect auditory development. In comparison to healthy full-term infants, preterm infants show abnormal auditory brain responses at term age, which may have long-term detrimental outcomes. To achieve an optimal neonatal care environment for preterm-born infants, many early interventions have been developed. Musical interventions developed for neonatal intensive care units (NICUs) have shown beneficial effects on vital functions and weight gain of preterm infants and might also influence basic auditory processing and thereby enhance outcomes. In the present study, we tested the effect of parental singing during kangaroo care on auditory processing of standardized audio stimuli. Preterm infants (born between 24 and 32 weeks of gestation) were randomized to singing intervention (n = 13) or control (n = 8) groups. The auditory processing was tested using two audio paradigms assessed with magnetoencephalography (MEG) at term corresponding age. To verify that the paradigms elicit responses in MEG, we studied 12 healthy full-term infants. In the singing intervention group, parents were instructed by a music therapist twice a week for 4 weeks to sing or hum during kangaroo care in an infant-directed way. The control group received standard kangaroo care. The results show that the infants in the singing intervention group show larger neural responses than those in the control group when controlling for the total amount of singing during kangaroo care. Our findings suggest that incorporating singing into kangaroo care may be beneficial for preterm infants, but the effect may not be due to exposure to singing but instead positive parenting, improved parental self-esteem and improved caregiver sensitivity.

Gender differential item functioning analysis in measuring computational thinking disposition among secondary school students

Computational thinking refers to the cognitive processes underpinning the application of computer science concepts and methodologies to the methodical approach and creation of a solution to a problem. The study aims to determine how students' cognitive, affective, and conative dispositions in using computational thinking are influenced by a gender. This study used a survey research design with quantitative approach. Five hundred thirty-five secondary school students were sampled using probability sampling with the Computational Thinking Disposition Instrument (CTDI). WINSTEPS version 3.71.0 software was subsequently employed to assess the Gender Differential item functioning (GDIF) including reliability and validity with descriptive statistics were employed to assess students' disposition toward practicing computational thinking. In addition to providing implications for the theory, the data give verifiable research that the CT disposition profile consists of three constructs. In addition, the demonstrated CTDI has good GDIF features, which may be employed to evaluate the efficacy of the application of CT in the Malaysian curriculum by measuring the level of CT in terms of the disposition profile of students.

EEG signatures of cognitive and social development of preschool children-a systematic review

Background

Early identification of preschool children who are at risk of faltering in their development is essential to ensuring that all children attain their full potential. Electroencephalography (EEG) has been used to measure neural correlates of cognitive and social development in children for decades. Effective portable and low-cost EEG devices increase the potential of its use to assess neurodevelopment in children at scale and particularly in low-resource settings. We conducted a systematic review aimed to synthesise EEG measures of cognitive and social development in 2-5-year old children. Our secondary aim was to identify how these measures differ across a) the course of development within this age range, b) gender and c) socioeconomic status (SES).

Methods and findings

A systematic literature search identified 51 studies for inclusion in this review. Data relevant to the primary and secondary aims was extracted from these studies and an assessment for risk of bias was done, which highlighted the need for harmonisation of EEG data collection and analysis methods across research groups and more detailed reporting of participant characteristics. Studies reported on the domains of executive function (n = 22 papers), selective auditory attention (n = 9), learning and memory (n = 5), processing of faces (n = 7) and emotional stimuli (n = 8). For papers investigating executive function and selective auditory attention, the most commonly reported measures were alpha power and the amplitude and latency of positive (P1, P2, P3) and negative (N1, N2) deflections of event related potential (ERPs) components. The N170 and P1 ERP components were the most commonly reported neural responses to face and emotional faces stimuli. A mid-latency negative component and positive slow wave were used to index learning and memory, and late positive potential in response to emotional non-face stimuli. While almost half the studies described changes in EEG measures across age, only eight studies disaggregated results based on gender, and six included children from low income households to assess the impact of SES on neurodevelopment. No studies were conducted in low- and middle-income countries.

Conclusion

This review has identified power across the EEG spectrum and ERP components to be the measures most commonly reported in studies in which preschool children engage in tasks indexing cognitive and social development. It has also highlighted the need for additional research into their changes across age and based on gender and SES.

Functional Brain Connectivity of Language Functions in Children Revealed by EEG and MEG: A Systematic Review

The development of language functions is of great interest to neuroscientists, as these functions are among the fundamental capacities of human cognition. For many years, researchers aimed at identifying cerebral correlates of language abilities. More recently, the development of new data analysis tools has generated a shift toward the investigation of complex cerebral networks. In 2015, Weiss-Croft and Baldeweg published a very interesting systematic review on the development of functional language networks, explored through the use of functional magnetic resonance imaging (fMRI). Compared to fMRI and because of their excellent temporal resolution, magnetoencephalography (MEG) and electroencephalography (EEG) provide different and important information on brain activity. Both therefore constitute crucial neuroimaging techniques for the investigation of the maturation of functional language brain networks. The main objective of this systematic review is to provide a state of knowledge on the investigation of language-related cerebral networks in children, through the use of EEG and MEG, as well as a detailed portrait of relevant MEG and EEG data analysis methods used in that specific research context. To do so, we have summarized the results and systematically compared the methodological approach of 24 peer-reviewed EEG or MEG scientific studies that included healthy children and children with or at high risk of language disabilities, from birth up to 18 years of age. All included studies employed functional and effective connectivity measures, such as coherence, phase locking value, and Phase Slope Index, and did so using different experimental paradigms (e.g., at rest or during language-related tasks). This review will provide more insight into the use of EEG and MEG for the study of language networks in children, contribute to the current state of knowledge on the developmental path of functional connectivity in language networks during childhood and adolescence, and finally allow future studies to choose the most appropriate type of connectivity analysis.

Neonatal EEG linked to individual differences in socioemotional outcomes and autism risk in toddlers

Research using electroencephalography (EEG) as a measure of brain function and maturation has demonstrated links between cortical activity and cognitive processes during infancy and early childhood. The current study examines whether neonatal EEG is correlated with later atypical socioemotional behaviors or neurocognitive delays. Parental report developmental assessments were administered to families with children ages 24 to 36 months who had previously participated in a neonatal EEG study (N = 129). Significant associations were found between neonatal EEG (higher frequencies in the frontal polar, temporal, and parietal brain regions) and BITSEA ASD risk scores. Infants with lower EEG power in these brain areas were more likely to have higher risk of socioemotional problems. When examining sex differences, significant links were found for males but not for females. These results demonstrate some promising associations between early neural biomarkers and later risk for atypical behaviors, which may shape early neurobehavioral development and could lead to earlier identification and intervention.

Influence of Different Visual Perceptual Constructs on Academic Achievement Among Learners in the NW-CHILD Study

Visual perception plays an important and integrating role in the development of cognitive abilities and perceptual-motor skills. Visual perception comprises different independent constructs that may function in an integrative manner. This study aimed to determine whether (and the extent to which) various visual-perceptual constructs influence the academic achievement of 12-year-old school children. In a cross-sectional analysis, we extracted only 2016 data from 581 learners (mean age = 12.92 years, SD = 0.42) who were participants in the North-West Child Health, Integrated with Learning and Development longitudinal study (2010-2016). We used the Test of Visual Perceptual Skills, Third Edition, the North-West Provincial Assessment and mid-year school examination reports to determine visual perceptual abilities and academic achievement of this participant group. We calculated correlations between visual perceptual constructs and academic performance using Spearman rank order correlations and separately analyzed the influence of gender and socioeconomic status with independent T tests. Different visual perceptual constructs did have significant influences on specific areas of academic learning and on academic achievement generally ( r = .26 to r = .41). Spatial relationships showed slightly greater correlations with academic achievement ( r = .15 to r = .33) than did other basic visual perceptual constructs, possibly because spatial relationships are not completely developed at age 12. Complex and basic visual perceptual skills had medium significant retrospective correlations with grade point average ( r = .40 and r = .41) and first additional language ( r = .30 and r = .33). We concluded that basic and complex visual perceptual constructs remain important for academic achievement in this age-group, while gender and socioeconomic status influence both visual perceptual abilities and academic achievement.

A systematic literature review of sex differences in childhood language and brain development

The extent of sex differences in childhood language development is unclear. We conducted a systematic literature review synthesizing results from studies examining sex differences in brain structure and function relevant to language development during childhood. We searched PubMed and Scopus databases, and this returned a total of 46 published studies meeting criteria for inclusion that directly examined sex differences in brain development relevant to language function in children. The results indicate that: (a) sex differences in brain structure or function do not necessarily lead to differences in language task performance; (b) evidence for sex differences in brain and language development are limited; (c) when present, sex differences often interact with a variety of factors such as age and task. Overall, the magnitude of sexual dimorphism of brain developmental trajectories associated with language is not as significant as previously thought. Sex differences were found, however, in studies employing tighter age ranges. This suggests that sex differences may be more prominent during certain developmental stages but are negligible in other stages, likely due to different rates of maturation between the sexes. More research is needed to improve our understanding of how sex differences may arise due to the influence of sex hormones and developmental stages, and how these differences may lead to differences in various language task performance. These studies are expected to provide normative information that may be used in studies examining neurodevelopmental disorders that frequently affect more males than females, and also often affect language development.

Effectiveness of mindfulness-based colouring for test anxiety in adolescents

The purpose of this study was to compare the effectiveness of a mindfulness art activity (mandala) with a free draw/colouring activity on test anxiety in adolescents with an examination of gender differences, and to assess the effect of dispositional mindfulness on students’ experience of mindfulness and test anxiety states. Participants were 193 Grade 8 students (56.6% female; Mage = 13.49 years, SD = 0.50) randomly assigned to a mandala ( n = 97) or free draw/colouring condition ( n = 96). Students completed standardized measures to assess test anxiety and state mindfulness pre- post-colouring intervention, immediately prior to completing a test, in addition to a measure of dispositional mindfulness. Results showed a significant decrease in test anxiety and a significant increase in state mindfulness following both activities; however, a gender by group by time interaction was found such that females reported a greater decrease in test anxiety in the free condition compared to males. Furthermore, the baseline measures (pre-intervention state mindfulness and test anxiety) were found to fully mediate relations between dispositional mindfulness and the outcome measures (post-intervention state mindfulness and test anxiety). Implications for educators and future research and practice regarding the use of mindfulness activities in the classroom are discussed.

Developmental trends of theta-beta interelectrode power correlation during resting state in normal children

The possibility that power-to-power (theta-beta) frequency coupling increases during development was analyzed. Three minutes of spontaneous EEG in an open eyes condition were recorded in a sample of 160 subjects ranging from 6 to 26 years old. Theta (4-7 Hz) and beta band (15-20 Hz) power was calculated in a trial-by-trial basis. Inter-electrode power correlations (IPC) were computed in each subject as the correlation between the power of two frequency bands recorded in two electrodes. An increase in theta-beta IPC with age was obtained. IPCs were higher when theta was seeded in posterior regions than in anterior or central regions. Moreover, the significant correlations between each individual IPC and age were calculated, making it possible to draw IPC versus age correlation maps in order to capture the IPC development topography. An increase was found in significant correlations in the left hemisphere compared to the right hemisphere. There were no differences in the inter-hemispheric versus intra-hemispheric IPC maturation spatial patterns. An increase in power-to-power-frequency coupling in theta-beta occurs during development, suggesting an increase in functional connectivity with age. Frequency coupling between theta and beta rhythms would be one of the mechanisms facilitating integration of long distance functional networks during development.

Are sex differences in fundamental motor skills uniform throughout the entire preschool period?

The aim of this study was to assess differences in fundamental motor skills (FMS) proficiency between boys and girls of each age group, independently, across the entire preschool period. Using the Movement Assessment Battery for Children-second edition, FMS proficiency was tested in 325 preschoolers (4.9 ± 1.1 y, range 3-6) using a cross-sectional design. Compared to boys of the same age, 3- and 4-year-old girls had greater total (p < .01), fine motor skill (p < .01), and balance scores (p < .05). There were no sex differences for total test or balance scores in 5- and 6-year-olds, but 6-year-old boys outperformed girls in aiming and catching (p < .001). These data not only agree with previous research in that sex differences in FMS proficiency exist in preschool children, but the data also show that differences may not be uniform throughout the whole preschool period when analyzing by age. To avoid under- or overestimating FMS proficiency and subsequently prescribing inaccurate motor intervention programs, FMS proficiency normative values should be age- and sex-specific throughout the entire preschool period.

Hemispheric Coherence in ASD with and without Comorbid ADHD and Anxiety

There is a growing body of evidence suggesting that altered brain connectivity may be a defining feature of disorders such as autism spectrum disorder (ASD), anxiety, and ADHD. This study investigated whether resting state functional connectivity, measured by 128-channel EEG oscillation coherence, differs between developmental disorders. Analyses were conducted separately on groups with and without comorbid conditions. Analyses revealed increased coherence across central electrodes over the primary motor cortex and decreased coherence in the frontal lobe networks in those with ASD compared to neurotypical controls. There was increased coherence in occipital lobe networks in the ADHD group compared to other groups. Symptoms of generalised anxiety were positively correlated with both frontal-occipital intrahemispheric (alpha only) coherence and occipital interhemispheric coherence (alpha, approaching theta band). The patterns of coherence in the ASD pure group were different when comorbid conditions were included in the analyses, suggesting that aberrant coherence in the frontal and central areas of the brain is specifically associated with ASD. Our findings support the idea that comorbid conditions are additive, rather than being symptoms of the same disorder.

Age differences in high frequency phasic heart rate variability and performance response to increased executive function load in three executive function tasks

The current study examines similarity or disparity of a frontally mediated physiological response of mental effort among multiple executive functioning tasks between children and adults. Task performance and phasic heart rate variability (HRV) were recorded in children (6 to 10 years old) and adults in an examination of age differences in executive functioning skills during periods of increased demand. Executive load levels were varied by increasing the difficulty levels of three executive functioning tasks: inhibition (IN), working memory (WM), and planning/problem solving (PL). Behavioral performance decreased in all tasks with increased executive demand in both children and adults. Adults' phasic high frequency HRV was suppressed during the management of increased IN and WM load. Children's phasic HRV was suppressed during the management of moderate WM load. HRV was not suppressed during either children's or adults' increasing load during the PL task. High frequency phasic HRV may be most sensitive to executive function tasks that have a time-response pressure, and simply requiring performance on a self-paced task requiring frontal lobe activation may not be enough to generate HRV responsitivity to increasing demand.

Secure attachment promotes the development of effortful control in boys

Although effortful control (EC), a regulatory aspect of temperament, is associated with a wide range of developmental outcomes, knowledge about EC promoters is scarce. This study explored whether secure attachment promoted the development of EC from preschool to school age in a community sample of 903 Norwegian children. EC was measured using the parent-reported Children's Behavior Questionnaire at four (T1) and six (T2) years of age, and attachment was measured using the Manchester Child Attachment Story Task at T1. Previous research has indicated that a child's gender and socioeconomic status are possible covariates of EC; hence, these factors were included in the analyses. Despite considerable rank-order stability in EC, secure attachment contributed to an increase in EC. Furthermore, gender moderated the effect of attachment: secure attachment promoted EC in boys only. These findings emphasize preschool boys' need for emotional security to facilitate effortful capacities in their transition to school.

Cognitive processes associated with compulsive buying behaviours and related EEG coherence

The behavioural and cognitive phenomena associated with Compulsive Buying (CB) have been investigated previously but the underlying neurophysiological cognitive process has received less attention. This study specifically investigated the electrophysiology of CB associated with executive processing and cue-reactivity in order to reveal differences in neural connectivity (EEG Coherence) and distinguish it from characteristics of addiction or mood disorder. Participants (N=24, M=25.38 yrs, S.D.=7.02 yrs) completed the Sensitivity to Punishment Sensitivity to Reward Questionnaire and a visual memory task associated with shopping items. Sensitivities to reward and punishment were examined with EEG coherence measures for preferred and non-preferred items and compared to CB psychometrics. Widespread EEG coherence differences were found in numerous regions, with an apparent left shifted lateralisation for preferred and right shifted lateralisation for non-preferred items. Different neurophysiological networks presented with CB phenomena, reflecting cue reactivity and episodic memory, from increased arousal and attachment to items.

Age-related changes in EEG coherence

BACKGROUND AND PURPOSE

Coherence changes can reflect the pathophysiological processes involved in human ageing. We conducted a retrospective population study that sought to analyze the age-related changes in EEG coherence in a group of 17,722 healthy professional drivers.

MATERIALS AND METHODS

The EEGs were obtained using a standard 10-20 electrode configuration on the scalp. The recordings from 19 scalp electrodes were taken while the participants' eyes were closed. The linear correlations between the age and coherence were estimated by linear regression analysis.

RESULTS

Our results showed a significant decrease in coherence with age in the theta and alpha bands, and there was an increasing coherence with the beta bands. The most prominent changes occurred in the alpha bands. The delta bands contained movement artefacts, which most likely do not change with age.

CONCLUSIONS

The age-related EEG desynchrony can be partly explained by the age-related reduction of cortical connectivity. Higher frequencies of oscillations require less cortical area of high coherence. These findings explain why the lowest average coherence values were observed in the beta and sigma bands, as well as why the beta bands show borderline statistical significance and the sigma bands show non-significance. The age-dependent decrease in coherence may influence the estimation of age-related changes in EEG energy due to phase cancellation.

Children's computation of complex linguistic forms: a study of frequency and imageability effects

This study investigates the storage vs. composition of inflected forms in typically-developing children. Children aged 8–12 were tested on the production of regular and irregular past-tense forms. Storage (vs. composition) was examined by probing for past-tense frequency effects and imageability effects – both of which are diagnostic tests for storage – while controlling for a number of confounding factors. We also examined sex as a factor. Irregular inflected forms, which must depend on stored representations, always showed evidence of storage (frequency and/or imageability effects), not only across all children, but also separately in both sexes. In contrast, for regular forms, which could be either stored or composed, only girls showed evidence of storage. This pattern is similar to that found in previously-acquired adult data from the same task, with the notable exception that development affects which factors influence the storage of regulars in females: imageability plays a larger role in girls, and frequency in women. Overall, the results suggest that irregular inflected forms are always stored (in children and adults, and in both sexes), whereas regulars can be either composed or stored, with their storage a function of various item- and subject-level factors.

Coherence, phase differences, phase shift, and phase lock in EEG/ERP analyses

Electroencephalogram (EEG) coherence is a mixture of phase locking interrupted by phase shifts in the spontaneous EEG. Average reference, Laplacian transforms, and independent component (ICA) reconstruction of time series can distort physiologically generated phase differences and invalidate the computation of coherence and phase differences as well as in the computation of directed coherence and phase reset. Time domain measures of phase shift and phase lock are less prone to artifact and are independent of volume conduction. Cross-frequency synchrony in the surface EEG and in Low Resolution Electromagnetic Tomography (LORETA) provides insights into dynamic functions of the brain.

Developmental trends in auditory processing can provide early predictions of language acquisition in young infants

Auditory processing capabilities at the subcortical level have been hypothesized to impact an individual's development of both language and reading abilities. The present study examined whether auditory processing capabilities relate to language development in healthy 9-month-old infants. Participants were 71 infants (31 boys and 40 girls) with both Auditory Brainstem Response (ABR) and language assessments. At 6 weeks and/or 9 months of age, the infants underwent ABR testing using both a standard hearing screening protocol with 30 dB clicks and a second protocol using click pairs separated by 8, 16, and 64-ms intervals presented at 80 dB. We evaluated the effects of interval duration on ABR latency and amplitude elicited by the second click. At 9 months, language development was assessed via parent report on the Chinese Communicative Development Inventory - Putonghua version (CCDI-P). Wave V latency z-scores of the 64-ms condition at 6 weeks showed strong direct relationships with Wave V latency in the same condition at 9 months. More importantly, shorter Wave V latencies at 9 months showed strong relationships with the CCDI-P composite consisting of phrases understood, gestures, and words produced. Likewise, infants who had greater decreases in Wave V latencies from 6 weeks to 9 months had higher CCDI-P composite scores. Females had higher language development scores and shorter Wave V latencies at both ages than males. Interestingly, when the ABR Wave V latencies at both ages were taken into account, the direct effects of gender on language disappeared. In conclusion, these results support the importance of low-level auditory processing capabilities for early language acquisition in a population of typically developing young infants. Moreover, the auditory brainstem response in this paradigm shows promise as an electrophysiological marker to predict individual differences in language development in young children.

Conceptualizing men: a transdiagnostic model of male distress

PURPOSE

This review aims to produce a comprehensive, parsimonious, and empirically based model of male psychological distress from the perspective of cognitive behaviour therapy (CBT) that may apply in the majority of clinical situations involving men in Britain and possibly elsewhere.

METHODS

This paper reviews studies that pertain to male psychological distress. Studies are selected via examination of the literatures around men's psychological health. Criteria for inclusion of studies are direct and indirect relevance to male distress. Studies are examined on the basis of their possible contribution to a comprehensive yet critical model of male functioning, and are grouped according to their neurological, developmental, and cultural origins.

RESULTS

The review suggests that certain factors inform the psychological presentation of males across disorders, and can help predict therapy-interfering behaviours and outcomes. A transdiagnostic model of male distress emerges from existing data and theory containing the hypothesized reflection abandonment mechanism (RAM) that helps account for characteristic male externalizing and therapy-interfering behaviours.

CONCLUSIONS

Existing data and theory can be synthesized to produce a cognitive behavioural model of male distress that adds value to case conceptualizations regardless of the disorder involved, and has predictive value regarding men's access to and engagement with psychological services.

Neurocognitive development and externalizing problems: the role of inhibitory control deficits from 4 to 6 years

Executive processes have been posited as important regulators of externalizing problems (EP), but there has been little research on the relation between executive dysfunction and EP in early childhood. During the preschool period, maturation of the prefrontostriatal circuitry parallels increases in inhibitory control (IC). Poor IC development could result in elevated levels of aggressive, disruptive, and impulsive behavior. In this investigation, the development of the relation between IC and EP was examined in preschool and early elementary school children using the Day/Night and Tapping tasks. Children with more EP made more incorrect responses on both IC tasks, consistently across age and sex. The associations between EP and response latencies differed across children, however, with longer latencies on the Tapping task being most characteristic for boys with high levels of EP. This association was not apparent for girls. Two prominent aspects of early EP, aggressive and inattentive behavior, showed only weak unique associations with IC performance. These findings imply that diminished IC accompanies elevated EP as early as the preschool years, and that this decrement persists into the elementary school-age years for both girls and boys, and that accuracy and response latency may confer different information about the development of IC.

Handedness and Drawing: Attempting to Complete the Picture: A Comment on Bruckner, Et Al. (2011)

In a recent study, Bruckner, Kastner-Koller, Deimann, and Voracek (2011) investigated the relationship between hand preference and drawing during preschool years. The present study offers interpretations in a larger framework which could contribute to the better understanding of that relationship, and provides future directions in this area.

Network analysis of resting state EEG in the developing young brain: structure comes with maturation

During childhood, brain structure and function changes substantially. Recently, graph theory has been introduced to model connectivity in the brain. Small-world networks, such as the brain, combine optimal properties of both ordered and random networks, i.e., high clustering and short path lengths. We used graph theoretical concepts to examine changes in functional brain networks during normal development in young children. Resting-state eyes-closed electroencephalography (EEG) was recorded (14 channels) from 227 children twice at 5 and 7 years of age. Synchronization likelihood (SL) was calculated in three different frequency bands and between each pair of electrodes to obtain SL-weighted graphs. Mean normalized clustering index, average path length and weight dispersion were calculated to characterize network organization. Repeated measures analysis of variance tested for time and gender effects. For all frequency bands mean SL decreased from 5 to 7 years. Clustering coefficient increased in the alpha band. Path length increased in all frequency bands. Mean normalized weight dispersion decreased in beta band. Girls showed higher synchronization for all frequency bands and a higher mean clustering in alpha and beta bands. The overall decrease in functional connectivity (SL) might reflect pruning of unused synapses and preservation of strong connections resulting in more cost-effective networks. Accordingly, we found increases in average clustering and path length and decreased weight dispersion indicating that normal brain maturation is characterized by a shift from random to more organized small-world functional networks. This developmental process is influenced by gender differences early in development.

Self-organized criticality and the development of EEG phase reset

OBJECTIVES

The purpose of this study was to explore human development of self-organized criticality as measured by EEG phase reset from infancy to 16 years of age.

METHODS

The electroencephalogram (EEG) was recorded from 19 scalp locations from 458 subjects ranging in age from 2 months to 16.67 years. Complex demodulation was used to compute instantaneous phase differences between pairs of electrodes and the 1st and 2nd derivatives were used to detect the sudden onset and offset times of a phase shift followed by an extended period of phase locking. Mean phase shift duration and phase locking intervals were computed for two symmetrical electrode arrays in the posterior-to-anterior locations and the anterior-to-posterior directions in the alpha frequency band (8-13 Hz).

RESULTS

Log-log spectral plots demonstrated 1/f (alpha) distributions (alpha approximately 1) with longer slopes during periods of phase shifting than during periods of phase locking. The mean duration of phase locking (150-450 msec) and phase shift (45-67 msec) generally increased as a function of age. The mean duration of phase shift declined over age in the local frontal regions but increased in distant electrode pairs. Oscillations and growth spurts from mean age 0.4-16 years were consistently present.

CONCLUSIONS

The development of increased phase stability in local systems is paralleled by lengthened periods of unstable phase in distant connections. Development of the number and/or density of synaptic connections is a likely order parameter to explain oscillations and growth spurts in self-organized criticality during human brain maturation.

Development of cortical connections as measured by EEG coherence and phase delays

The purpose of this study was to explore human development of EEG coherence and phase differences over the period from infancy to 16 years of age. The electroencephalogram (EEG) was recorded from 19 scalp locations from 458 subjects ranging in age from 2 months to 16.67 years. EEG coherence and EEG phase differences were computed for the left and right hemispheres in the posterior-to-anterior direction (O1/2-P3/4, O1/2-C3/4, O1/2-F3/4, and O1/2-Fp1/2) and the anterior-to- posterior direction (Fp1/2-F3/4, Fp1/2-C3/4, Fp1/2-P3/4, and Fp1/2-O1/2) in the beta frequency band (13-25 Hz). Sliding averages of EEG coherence and phase were computed using 1 year averages and 9 month overlapping that produced 64 means from 0.44 years of age to 16.22 years of age. Rhythmic oscillations in coherence and phase were noted in all electrode combinations. Different developmental trajectories were present for coherence and phase differences and for anterior-to-posterior and posterior-to-anterior directions and inter-electrode distance. Large changes in EEG coherence and phase were present from approximately 6 months to 4 years of age followed by a significant linear trend to higher coherence in short distance inter-electrode distances and longer phase delays in long inter-electrode distances. The results are consistent with a genetic model of rhythmic long term connection formation that occurs in cycles along a curvilinear trajectory toward adulthood. Competition for dendritic space, development of complexity, and nonlinear dynamic oscillations are discussed.

Age and gender effects in EEG coherence: I. Developmental trends in normal children

OBJECTIVE

This study investigated intra-hemispheric and inter-hemispheric EEG coherences as a function of age and gender in normal children.

METHODS

Two groups of 40 boys and 40 girls, each containing 8 normal children in each 1-year band from 8 to 12 years, participated. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for 8 intra-hemispheric electrode pairs (4 in each hemisphere), and 8 inter-hemispheric electrode pairs, within each of the delta, theta, alpha and beta bands.

RESULTS

There was consistent evidence of coherences developing across this age range, particularly in long-range intra- and inter-hemispheric electrode pairs. Coherences were larger in the left hemisphere than the right. Coherences also appeared to develop further in males than females, across several regions and frequency bands, suggesting that females lag males in this aspect of brain development.

CONCLUSIONS

EEG coherences in normal children of this age range develop systematically with age. These developmental effects vary substantially with gender, brain region and frequency bands.

SIGNIFICANCE

The data reported here provide basic norms for coherence development in different brain regions in normal children.

EEG Power and Coherence in Children with Educational Problems

SUMMARY

SUMMARY This study deals with the quantitative EEG (QEEG) of children attending schools for the mentally retarded and learning disabled. Questions are in which way do the EEGs of these children differ from normal development and whether deviations are restricted to a subgroup of children. The topographic distribution of EEG power is of particular interest. Based on a sample of n = 158 normal children, age-standardized values of absolute power (delta, theta, alpha 1, alpha 2, beta 1, beta 2 at F4, F3, C4, C3, CZ, PZ, O2, O1) and of coherence are computed for all children. The topographic distribution is assessed by analysis of variance (ANOVA) and by a principal component approach. The EEG of children with educational problems differs substantially from normal development in the slow bands and differs less in the fast bands. Deviations affect a subgroup of children, mainly children attending a school for the mentally retarded. Topographic distribution is an important factor in all bands. Coherence analysis leads to rather weak results that lack a clear interpretation. The QEEG is useful for understanding neurophysiological development in children with educational problems as a group more than individually. Parameters of topographic distribution provide strong additional information to power itself.