bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of disorder particles size of Nd on electrical transport on a bulk of Pr2/3Ba1/3MnO3
Authors: Abdullah H , Halim SA , Jannah AN
Published: February 2012

Polycrystalline samples of (Pr1– xNd x)0.67Ba0.33MnO3 with concentrations of x = 0.0, 0.167, 0.33, 0.5, 0.67, 0.833, and 1.0 have been prepared using solid-state reactions. The analysis of X-ray diffraction data revealed that all of the samples were found to crystallize in the orthorhombic structure. The electrical property, Tp, was determined by using standard four-point probe resistivity measurements in a temperature range of 30–300 K. A shift of the metal-insulator transition temperature, Tp, to a lower value was observed when Pr doping was increased. The electrical resistivity data was analyzed using various theoretical models, and it has been concluded that the resistivity of the samples in a low temperature regime ( T <  Tp) are well-fitted using the expression [Formula: see text], implying the importance of grain/domain boundaries and electron–electron and two magnon scattering processes. In the high temperature regime ( T >  Tp), the resistivity data can be well described by small polaron hopping and variable range hopping mechanisms. In the semi-conducting portion, the activation energy ( Ea) has been investigated. The Ea increased as the doping concentration increased. Scanning electron microscope micrographs showed that the substitution of Nd3+ ions for the Pr3+ site in LaBaMnO3 leads to grain growth inhibition, disorder in the grain size, praseodymium segregation, and second phase formation.
Optimization of fiber composition in natural fiber-reinforced composites using a simplex lattice design
Authors: Das Dipayan , Mukhopadhyay Samrat , Kaur Harpreet
Published: February 2012

Natural fiber-reinforced composites were prepared using jute, sisal, and coir fibers as the reinforcement and polypropylene as the matrix. Fiber proportion was varied as a part of the experimental design and composites were characterized for mechanical properties. A set of simple expressions were obtained for predicting the tensile properties of the composites as a function of the weight fraction of fibers in the blends. The predicted results of tensile properties of the composites were found in good agreement with the experimental results. It was observed that the composite made up of about 66% sisal fibers and 34% coir fibers showed optimum tensile properties.
A stable perturbation estimator in force-reflecting passivity-based teleoperation
Authors: Jafari A , Rezaei SM , Ghidary S Shiry , Zareinejad M , Baghestan K , Dehghan MR
Published: February 2012

Many researchers have focused on force tracking improvement in teleoperation systems. Various methods have been utilized to reach this aim. This paper focuses on force-reflecting passivity-based architecture. Adding a force error term to conventional passivity-based architecture, a controller has been introduced to improve transparency. A condition has been obtained, which guarantees the stability of the system, while it holds. Moreover, a sliding mode perturbation estimation algorithm has been proposed. The method proved to be asymptotically converging to perturbations. The transparency of system has been compared in simple and force-reflecting passivity-based architectures, and also with and without perturbation estimator. Experiments on a 2-DOF non-linear delayed teleoperation system were conducted to investigate the system’s performance. Experimental results have shown that the controller is stable and force tracking has been improved compared with previous research. Furthermore, the perturbation in the system has been successfully estimated and cancelled. Conclusively, the paper introduces a controller that is stable and compares its performance in force tracking with previous research.
The Interactional Organization of Self-praise
Authors: Speer Susan A.
Published: February 2012

This article contributes to a social psychological understanding of identity by identifying some features of the interactional organization of self-praise. Early conversation analytic work on the epistemics of self-assessment and constraints against self-praise has shown that praising oneself is an interactionally delicate matter that may leave one vulnerable to “unfavorable character assessment” or accusations of bragging (Pomerantz 1978:89). Drawing on data examples from a range of settings, this article develops Pomerantz’s work and examines the role of reported third-party compliments (e.g., “she . . . said ‘you look really lovely’”) in objectifying self-praise. Analyzing instances in which speakers initiate repair on their self-descriptions in favor of reported third-party compliments, I provide evidence of practices suggesting a norm against direct self-praise and an interactional preference for embedding positive self-descriptions within a third-party attribution. I consider the implications of these analyses for a social psychological understanding of identity and its measurement.
Adolescent Behavior and Health in Cross-Cultural Context
Authors: Demetrovics Zsolt
Published: February 2012

Specific behavioral problems appear during early adolescence, and they become more pronounced. Although these problems are universal in many aspects, cultural differences are also conspicuous. The author, in addition to analyzing the five studies in the Special Issue, addresses questions concerning the cross-cultural context. The analysis reveals that today the cross-cultural analysis of the causal relationships concerning problem behavior is at the forefront, surpassing the international comparative studies characterized by analyzing only prevalence data. The author analyzes the phenomena of mass media globalization and cultural migration, which are believed to play an important role in the cross-cultural convergence of numerous problematic phenomena. Cultural heterogeneity, however, has to be considered as well, often even within one single country. It has to be emphasized that in case of intercultural transmission of preventive and treatment interventions, cultural differences have to be considered.
Studies on Mechanical Behavior of Surface Modified Sisal Fibre – Epoxy Composites
Authors: Padmavathi T , Naidu S Venkata , Rao RMVGK
Published: February 2012

Studies were carried out on sisal-epoxy composites prepared with different fibre weight fractions (precisely determined by a novel thermogravimetric analyser technique) containing optimally treated (18% NaOH) sisal fibres, using an improvised fabrication approach. An enhancement of 110% in the optimally treated fibre tensile property resulted in improvement of composite mechanical properties (compression, tensile, interlaminar shear stress and energy absorption) ranging between 18% and 158%. A novel fibre treatment effectiveness parameter was introduced, to quantify the translation efficiency of the enhanced fibre tensile property into the composite tensile property. Scanning electron microscopic analysis of fractured composite specimens are also presented and discussed.
Exclusive Breastfeeding in the Hospital
Authors: Zakarija-Grković Irena
Published: February 2012

Background: Accurate hospital exclusive breastfeeding (EBF) rates, a core indicator of hospital performance, are important.

Objective: The aim of this study was to assess the accuracy of hospital infant feeding data by comparing EBF rates obtained from standard charts in which once-daily observations are recorded with new infant feeding charts in which every feed was documented.

Methods: In this cross-sectional study, 157 healthy mother-infant pairs were enrolled at the University Hospital of Split, Croatia, between February and May 2008. Infant feeding data were gathered from 4 sources: (1) standard once-daily observations recorded by pediatricians; (2) new, every-feed observations recorded by nursing staff; (3) interview with the mother before discharge; and (4) Newborn Examination Form, completed on discharge by the pediatrician. WHO definitions were used to determine EBF during the first 48 hours and from birth until discharge.

Results: Only 3% of infants were EBF throughout the hospital stay when calculated with the every-feed method, as opposed to 56% and 82%, with the once-daily and newborn examination methods, respectively ( P < .001). Maternal report confirmed the finding that 97% of infants were supplemented with formula, indicating that most formula supplements are not recorded in the standard once-daily charts.

Conclusions: Accurate documentation of infant feeding practices is essential for obtaining reliable EBF rates. This study shows that once-daily recordings of infant feeding practices grossly underestimate the prevalence of formula supplementation in breastfed infants, resulting in significantly higher, erroneous EBF rates.
“I’m in Control”
Authors: Ezzell Matthew B.
Published: February 2012

Based on participant observation and in-depth interviews, this article analyzes the ways that male residents in a drug treatment program signified a masculine self through compensatory manhood acts. I analyze four strategies of identity work that men used during group accountability sessions called “games”: (1) signifying masculinity through aggression; (2) subordinating women and nonconventional men; (3) calling others to account as men; and (4) “keeping your head”: managing emotions to (re)assert control. This article adds to our understanding of the ways that compensatory manhood acts are structured locally through interaction, highlighting ways that men’s interactions may be self-defeating and also reproduce inequality by reinforcing dominant ideologies of misogyny and homophobia. In addition, it speaks to the ways that masculine subjectivity is constructed against and through dominant narratives of addiction and treatment.
Evaluation of a procedure for positioning a crash test dummy in a railway vehicle
Authors: Chevalier Marie-Christine , Matthews Peter , Hanen Gaëtan , Jumin Patrick , Stubbs Deborah , Roure Bernard
Published: February 2012

This technical note focuses on the evaluation of a procedure for positioning a crash test dummy in a rail environment before physical testing. Through physical implementation, a simple approach consisting of adjusting the location of the dummy on the seat was evaluated and validated. The data collected was used to accurately align a virtual dummy with real-life information demonstrating that the procedure, coupled with virtual modelling, provides a powerful research tool by which to improve the passive safety of passengers travelling in rail vehicles.
Long-term administration of Silymarin augments proinflammatory mediators in the hippocampus of rats: Evidence for antioxidant and pro-oxidant effects
Authors: Malekinejad H , Rahmani F , Valivande-Azar S , Taheri-Broujerdi M , Bazargani-Gilani B
Published: February 2012

Silymarin (SMN) is used as an antioxidant complex to attenuate the pro-oxidant effects of toxic agents. This study was designed to investigate the impact of a long-term administration of SMN on proinflammatory mediators, oxidative stress biomarkers and on the levels of interleukin-1β (IL-1β) transcript in the hippocampus. A total of 40 adult male Wistar rats were assigned into control and test groups. Animals in the test group were subdivided into four subgroups according to the following treatment profile: carbon tetrachloride (CCl4, 0.5 ml/kg), SMN 25, SMN 50 and SMN 100 (mg/kg). The animals received the compounds by gastric gavage. Following the 8-week treatment period, animals in the CCl4 group showed body weight loss, while the test groups except SMN 100 revealed a significant ( p < 0.05) positive body weight gain. The levels of nitric oxide (NO) and malondialdehyde (MDA) as pro-oxidant and lipid peroxidation index, respectively, increased in CCl4- and SMN 100-treated groups, while SMN at lower dose levels did not alter the NO and MDA content. The concentration of total thiol molecules increased in the SMN 50 group and showed a remarkable decrease in CCl4 and SMN 100 groups. Animals treated with CCl4 or SMN 100 showed an upregulation of IL-1β, while animals in SMN 25 and SMN 50 groups showed a slight downregulation of expression of IL-1β at the messenger RNA level. These findings suggest that SMN at higher dosage level might exert pro-oxidant effect as an increase in the level of MDA and proinflammatory mediators such as NO, and upregulation of IL-1β in the hippocampus were shown.
Nonverbal Cognitive Development in Children With Cochlear Implants
Authors: Caudle Susan E. , Katzenstein Jennifer M. , Oghalai John S. , Lin Jerry , Caudle Donald D.
Published: February 2012

Methodologically, longitudinal assessment of cognitive development in young children has proven difficult because few measures span infancy through school age. This matter is further complicated when the child presents with a sensory deficit such as hearing loss. Few measures are validated in this population, and children who are evaluated for cochlear implantation are often reevaluated annually. The authors sought to evaluate the predictive validity of subscales of the Mullen Scales of Early Learning (MSEL) on Leiter International Performance Scales–Revised (LIPS-R) Full-Scale IQ scores. To further elucidate the relationship of these two measures, comparisons were also made with the Vineland Adaptive Behavior Scale–Second Edition (VABS), which provides a measure of adaptive functioning across the life span. Participants included 35 children (14 female, 21 male) who were evaluated both as part of the precandidacy process for cochlear implantation using the MSEL and VABS and following implantation with the LIPS-R and VABS. Hierarchical linear regression revealed that the MSEL Visual Reception subdomain score significantly predicted 52% of the variance in LIPS-R Full-Scale IQ scores at follow-up, F(1, 34) = 35.80, p < .0001, R2 = .52, β = .72. This result suggests that the Visual Reception subscale offers predictive validity of later LIPS-R Full-Scale IQ scores. The VABS was also significantly correlated with cognitive variables at each time point.
Synchronization and suppression of chaos in an electromagnetic system
Authors: Chang Shun-Chang
Published: February 2012

In this study, various nonlinear dynamic analysis techniques are employed to reveal the rich nonlinear phenomena of an electromagnetic system. In particular, bifurcation diagrams, time responses, phase portraits, Poincare maps, power spectrum analysis, and the construction of basins of attraction are all powerful and effective tools for nonlinear dynamic problems. The Lyapunov exponent method is employed to show the occurrence of chaotic motion and to verify the numerical simulation results. Finally, two cases of a chaotic electromagnetic system being effectively controlled by a reference signal or being synchronized to another nonlinear electromagnetic system are presented.
A Neuropsychological Perspective on Attention Problems in Neurofibromatosis Type 1
Authors: Templer Alexandra K. , Titus Jeffrey B. , Gutmann David H.
Published: February 2012

Cognitive problems are common in children with neurofibromatosis type 1 and they can often complicate treatment. The current literature review examines cognitive functioning in neurofibromatosis type 1, with a specific focus on executive functioning. This includes exploration of how deficits in executive functioning are expressed in children with neurofibromatosis type 1 and how these deficits contrast with ADHD. The value of investigating subcomponents of executive functioning is discussed, as are implications for effective treatment and future research.
Test–retest reliability of pulse amplitude tonometry measures of vascular endothelial function: Implications for clinical trial design
Authors: McCrea Cindy E , Skulas-Ray Ann C , Chow Mosuk , West Sheila G
Published: February 2012

Endothelial dysfunction is an important outcome for assessing vascular health in intervention studies. However, reliability of the standard non-invasive method (flow-mediated dilation) is a significant challenge for clinical applications and multicenter trials. We evaluated the repeatability of pulse amplitude tonometry (PAT) to measure change in pulse wave amplitude during reactive hyperemia (Itamar Medical Ltd, Caesarea, Israel). Twenty healthy adults completed two PAT tests (mean interval = 19.5 days) under standardized conditions. PAT-derived measures of endothelial function (reactive hyperemia index, RHI) and arterial stiffness (augmentation index, AI) showed strong repeatability (intra-class correlations = 0.74 and 0.83, respectively). To guide future research, we also analyzed sample size requirements for a range of effect sizes. A crossover design powered at 0.90 requires 28 participants to detect a 15% change in RHI. Our study is the first to show that PAT measurements are repeatable in adults over an interval greater than 1 week.
Of mobile phones and mother-fathers: Calls, text messages, and conjugal power relations in mother-away Filipino families
Authors: Cabanes Jason Vincent A. , Acedera Kristel Anne F.
Published: February 2012

This article examines how the mobile phone might matter in the exercise of conjugal power relations between left-behind fathers and migrant mothers in transnational Filipino families. Drawing on in-depth interviews of ten pairs of fathers and children from mother-away families, it reveals that the mobile phone provides parents avenues to both expand and hold on to their traditionally gender-differentiated roles. This means that while the technology mitigates some of the effects of migration, it also complicates the already complex relationships between these fathers and mothers. Unfortunately, this situation tends to amplify the tremendous difficulties of having to deal with two opposing forces: the changed realities in a transnational Filipino family and the traditional expectations of Philippine society. So while the mobile phone can lead to increasing cooperation between left-behind fathers and migrant mothers, it has mostly resulted in exacerbating the already tremendous chasms that divide them.
Reporting an Alliance Using an Integrative Approach to the Management of Lymphedema in India
Authors: Ryan Terence J. , Narahari Saravu R.
Published: February 2012

In India 553 million persons are estimated to live in areas endemic for LF; approximately 21 million have symptomatic filariasis. Of the approximately 16.02 million cases of lymphedema caused by LF globally, 7.44 million (46.4%) are in India. India had seen diethyl carbamizine, and/or albendazole, delivered to whole populations, beginning the project to eliminate the disease. But new populations have developed the infection. In 2003 the need in resource-poor countries for morbidity control of lymphatic filariasis (LF) became clear, prompting the study by the Institute of Applied Dermatology in Kerala, India. Under this study,self help and family members assisted in home-based care, combining compression bandaging, yoga exercises, heat therapy using steaming, and skin care according to Ayurvedic medicine. Lymphedema presents with different patterns in the skin with gross changes in the epidermis, dermis, or subcutaneous tissue. Skilled and time-consuming counselling is important to give patients support. An almost immediate reduction in inflammatory episodes from 80.4% to 8.6% shows up within 2 or 3 weeks, and therefore, intake of antibiotics can be stopped. The second major response is reduction in the size of the limb. Volume reduction for large-sized limbs at 3 months is 39%, with a confidence interval of 4.9 to 5.9 L.
Auditory and Visual P300 Evoked Potentials Do Not Predict Response to Valproate Treatment of Aggression in Patients with Borderline and Antisocial Personality Disorders
Authors: Reeves Roy R. , Struve Frederick A. , Patrick Gloria
Published: February 2012

In this study of patients with borderline personality disorder (BPD) or antisocial personality disorder (ASPD) hospitalized because of aggressive behavior, auditory and visual P300 evoked potentials were obtained prior to treatment with valproate. Eight ASPD patients (8 males, 0 females) and 11 BPD patients (2 males, 9 females) showed improvement, while in 7 patients with ASPD (7 males, 0 females) and 10 patients with BPD (2 males, 8 females), aggression was not improved. Differences in auditory and visual P300 latencies and amplitudes were not significant for either diagnosis, or for both diagnoses combined. These findings suggest that auditory or visual P300 evoked potentials may not be useful for predicting response of aggressive behavior to valproate treatment in patients with BPD or ASPD.
EEG Mapping and Low-Resolution Brain Electromagnetic Tomography (LORETA) in Diagnosis and Therapy of Psychiatric Disorders: Evidence for a Key-Lock Principle
Authors: Saletu Bernd , Anderer Peter , Saletu-Zyhlarz Gerda M. , Pascual-Marqui Roberto D.
Published: February 2012

Different psychiatric disorders, such as schizophrenia with predominantly positive and negative symptomatology, major depression, generalized anxiety disorder, agoraphobia, obsessive-compulsive disorder, multi-infarct dementia, senile dementia of the Alzheimer type and alcohol dependence, show EEG maps that differ statistically both from each other and from normal controls. Representative drugs of the main psychopharmacological classes, such as sedative and non-sedative neuroleptics and antidepressants, tranquilizers, hypnotics, psychostimulants and cognition-enhancing drugs, induce significant and typical changes to normal human brain function, which in many variables are opposite to the above-mentioned differences between psychiatric patients and normal controls. Thus, by considering these differences between psychotropic drugs and placebo in normal subjects, as well as between mental disorder patients and normal controls, it may be possible to choose the optimum drug for a specific patient according to a keylock principle, since the drug should normalize the deviant brain function. This is supported by 3–dimensional low-resolution brain electromagnetic tomography (LORETA), which identifies regions within the brain that are affected by psychiatric disorders and psychopharmacological substances.
Frontal Alpha Power Asymmetry in Aggressive Children and Adolescents with Mood and Disruptive Behavior Disorders
Authors: Rybak Malgorzata , Crayton John W. , Young Irving J. , Herba Edward , Konopka Lukasz M.
Published: February 2012

Building on prior research, which has suggested a relationship between aggression and left frontal activity, our study tested the hypothesis that proneness to impulsive aggression would be related to relative left frontal overactivation. EEG one-hertz resting alpha power frontal asymmetry was examined in 65 pediatric male psychiatric patients with a history of impulsive aggression and comorbid mood and disruptive behavior disorders.

The strongest finding, which emerged from this analysis, was a finding of relative increases in left frontal activity compared with right frontal activity. The results also indicated that greater left frontal activity correlated positively with the severity of psychiatric disturbance. These findings suggest that relative increases in left frontal activity may be related to a locus of neurophysiological disruption associated with psychopathology characterized by behavioral and affective disinhibition. Results are discussed within a model of behavioral inhibition system-behavioral activation system theory.
Focal Seizures Originating from the Left Temporal Lobe in a Case with Chorea-Acanthocytosis
Authors: Tiftikcioglu Bedile Irem , Dericioglu Nese , Saygi Serap
Published: February 2012

Neuroacanthocytosis is a group of disorders, clinically characterized with movement disorders, self-mutilation and seizures. There is little information in the literature regarding the clinical and EEG findings of the accompanying seizures in this neurodegenerative disorder. A 46-year-old man who was diagnosed as chorea-acanthocytosis, a subgroup of neuroacanthocytosis, was investigated for severe drug resistant seizures. Continuous video-EEG monitoring revealed an active left temporal epileptogenic focus with left temporal rhythmic discharges detected during his complex partial seizures. T2-weighted cranial MRI indicated hyperintensity of the left amygdala as well as hyperintensity and atrophy of bilateral basal ganglia. We discuss the development of focal seizures in a patient who has a neurodegenerative disease, namely neuroacanthocytosis.
Pharmaco-EEG in Psychiatry
Authors: Mucci Armida , Volpe Umberto , Merlotti Eleonora , Bucci Paola , Galderisi Silvana
Published: February 2012

In spite of its origins deeply rooted in the discipline, pharmaco-EEG applications in psychiatry remain limited to its achievements in the field of psychotropic drugs classification and, in few instances, discovery.

In the present paper two attempts to transfer pharmaco-EEG methods to psychiatric clinical routine will be described: 1) monitoring of psychotropic drug toxicity at the central nervous system level, and 2) prediction of clinical response to treatment with psychotropic drugs. Both applications have been the object of several investigations providing promising and sometimes consistent findings which, however, had no impact on clinical practice. For the first topic, the review is limited to antipsychotics, lithium and recreational drugs, as for other psychotropic drugs mostly case studies are available, while for the response prediction it will include antipsychotics, antidepressants, anxiolytics, psychostimulants and nootropics.

In spite of several methodological limitations, pharmaco-EEG studies dealing with monitoring of antipsychotic- and lithium-induced EEG abnormalities went close to, but never became, a clinical routine. EEG studies of recreational drugs are flawed by several limitations, and failed, so far, to identify reliable indices of CNS toxicity to be used in clinical settings.

Several QEEG studies on early predictors of treatment response to first generation antipsychotics have produced consistent findings, but had no clinical impact. For other psychotropic drug classes few and inconsistent reports have appeared.

Pharmaco-EEG had the potential for important clinical applications, but so far none of them entered clinical routine. The ability to upgrade theories and methods and promote large scale studies represent the future challenge.
Alzheimer Disease: Caused by Primary Deficiency of the Cerebral Blood Flow
Authors: Niedermeyer E.
Published: February 2012

Alzheimer's disease (AD) is associated with considerably decreased cerebral blood flow (CBF) thought to be secondary, since dead neurons do not need oxygen and glucose. This view, however, needs to be critically re-examined.

The role of CBF in AD was submitted to a thorough analysis, raising the question: “Is there really a lack of demand in the presence of undisturbed blood supply?”

CBF decline is present in AD while the number of affected CNS systems is still quite small. The step-by-step evolution of AD mirrors a brain that progressively becomes ischemic. Areas related to memory function (hippocampus, temporal lobe cortex and vicinity) are bound to suffer first because of their particularly vulnerable blood supply.

This is the scenario of a disorder caused by primary and not by secondary CBF deficiency—a deficiency perhaps attributable to the upright gait of homo sapiens. This new approach also opens new avenues for treatment and prevention, which will be briefly discussed.
Interactive Effects of Hypertension and Alcohol Dependence on the P300 Event-Related Potential in African-Americans
Authors: Bauer Lance O. , Ceballos Natalie A. , Taylor Robert E.
Published: February 2012

Although hypertension and alcohol dependence have been linked by epidemiological surveys and clinical observations, their interactive effects on brain function have rarely been tested. The present study involved the recording of P300 event related potentials (ERP) from 106 middle-aged African-American adults assigned to one of four groups: normotensive/nondependent (n = 56), hypertensive/nondependent (n = 11), normotensive/dependent (n = 27), and hypertensive/dependent (n = 12). The numbers of Nicotine Dependence, Major Depressive Disorder, and Conduct Disorder symptoms were specified as covariates within a 2 by 2 factorial design. ERPs were recorded during separate visual and auditory oddball tasks.

The major result was a synergistic effect of hypertension and alcohol dependence on auditory P300 latency: the combination of both factors was associated with greater slowing than the sum of their independent effects. Future studies should continue to examine the potential synergistic effects of alcohol dependence and hypertension with a view toward identifying and reducing neurophysiological decrements and stroke risk among middle-aged patients.
Novelty Detection and Encoding for Declarative Memory within the Human Hippocampus
Authors: Grunwald Thomas , Kurthen Martin
Published: February 2012

Intracranial recordings of cognitive potentials within the human hippocampal system have identified N400 potentials in the anterior mesial temporal lobe (AMTL-N400) that correlate with verbal memory performance and are associated with novelty detection. Their amplitudes to “new” but not “old” words in a verbal recognition task correlate with the neuronal density of the hippocampal CA1-region and can be reduced selectively by the NMDA-receptor blocker ketamine. Moreover, it could be shown that NMDA-receptor dependent long-term potentiation (LTP), a form of synaptic plasticity with Hebbian characteristics, can be readily induced in human hippocampal slices but not in patients with hippocampal sclerosis. In these latter patients, we also found a reduction of AMTL-N400 amplitudes similar to the one induced by ketamine. In addition, we could show that hippocampal novelty detection is associated with successful encoding for declarative memory. Together, our findings suggest that successful encoding for declarative memory is at least in part mediated by NMDA-receptor dependent novelty detection within the human hippocampal system.
Visual Memory Deficits in Temporal Lobe Epilepsy: Toward a Multifactorial Approach
Authors: Vannucci M.
Published: February 2012

Temporal lobe epilepsies (TLE) are associated with material-specific memory deficits depending on the side of seizure origin. However, while verbal memory deficits have been consistently reported in patients with left-sided TLE, the relationship between visual memory deficits and right-sided TLE is more complex. Here, we review factors that influence the pattern of lateralization and the nature of visual memory impairments in TLE and discuss the possible relationship between these deficits and perceptual impairments in TLE patients.
Challenge Tests of Monoaminergic Systems: Neurophysiological Aspects
Authors: Norra Christine
Published: February 2012

Monoaminergic challenge tests allow investigating central nervous changes in humans under acute depletion of specific neurotransmitters (5-HT, DA, NE). Along with studies using alpha-methyl-para-tyrosine test (AMPT) and phenylalanine/tyrosine depletion test (APTD), the tryptophan depletion test (ATDT) represents the currently most established human challenge tool for the assessment of brain serotonin functioning. Neurophysiological studies in healthy and clinical samples may contribute to the search for a non-invasive and reliable biological marker of monoaminergic vulnerability or dysfunction. In the design of these studies, various biochemical and methodological aspects have to be taken into account. This article focuses on electrophysiological methodology and results of monoamine depletion studies (i.e., electroencephalography, magnetoencephalography, polysomnography, auditory evoked potentials and startle response).
Transcranial and Deep Brain Stimulation Approaches as Treatment for Depression
Authors: Rau Anne , Großheinrich Nicola , Palm Ulrich , Pogarell Oliver , Padberg Frank
Published: February 2012

Given that a considerable portion of depressed patients does not respond to or remit during pharmacotherapy, there is increasing interest in non-pharmacological strategies to treat depressive disorders. Several brain stimulation approaches are currently being investigated as novel therapeutic interventions beside electroconvulsive therapy (ECT), a prototypic method in this field with proven effectiveness. These neurostimulation methods include repetitive transcranial magnetic stimulation (rTMS), magnetic seizure therapy (MST), vagus nerve stimulation (VNS), deep brain stimulation (DBS) and transcranial direct current stimulation (tDCS). It is via different neuroanatomically defined “windows” that the various approaches access the neuronal networks showing an altered function in depression. Also, the methods vary regarding their degree of invasiveness. One or the other method may finally achieve antidepressant effectiveness with minimized side effects and constitute a new effective treatment for major depression.
Multimodality Imaging in a Depressed Patient with Violent Behavior and Temporal Lobe Seizures
Authors: Poprawski T. J. , Pluzyczka A. N. , Park Y. , Chennamchetty V. N. , Halaris A. , Crayton J. W. , Konopka L. M.
Published: February 2012

Patients suffering from epilepsy commonly experience behavioral symptoms. Behavioral manifestations are especially prevalent in patients with seizures originating in the limbic system. This case report illustrates how an objective, multimodality work-up can guide the clinician in the diagnosis and the treatment of a patient with a complex presentation.

After the discontinuation of some medications, the patient underwent a multimodality work-up that consisted of MRI, SPECT, and conventional and quantitative EEG (LORETA). In this case, the functional imaging studies showed a convergence of findings across the three modalities: MRI, SPECT and qEEG. Because of these findings, we supported more aggressive treatment of the seizure disorder. Ultimately this treatment resulted in resolution of the aggression and the depression.

In summary, when applied routinely, a comprehensive, systematic, diagnostic approach will minimize treatment false starts and failures, may reduce costs, and also, potentially decrease the severity and the duration of symptoms.
The Photoparoxysmal Response: The Probable Cause of Attacks during Video Games
Authors: Hughes John R.
Published: February 2012

Photic stimulation is part of a typical EEG in most countries, especially to check on the photoparoxysmal response (PPR). Interest in this response was enhanced in 1997 when hundreds of Japanese children had attacks while viewing a TV cartoon called “Pokemon.” The overall prevalence of the PPR among patients requiring an EEG is approximately 0.8%, but 1.7% in children and 8.87% in patients with epilepsy, more often in Caucasians and females. Autosomal dominant inheritance is indicated, and this response is seen especially at the wavelength of 700nm or at the flicker frequency of 15–18 Hz. The PPR extending beyond the stimulus carries no increased risk of seizures. Prognosis is generally good, especially after 20 years of age. Attention to PPR has been increased with the advent of video games, and the evoked seizures from these games are likely a manifestation of photosensitive epilepsy. Drug therapy has emphasized valproic acid, but Levetiracetam has also been successful in eliminating the PPR.
Ictal/Interictal EEG Patterns and Functional Neuroimaging Findings in Subcortical Band Heterotopia: Report of Three Cases and Review of the Literature
Authors: Dericioglu Nese , Oguz Kader Karli , Ergun Eser Lay , Tezer Fadime Írsel , Saygi Serap
Published: February 2012

Subcortical band heterotopia (SBH) is a rare, genetic disorder of neuronal migration, which is seen almost exclusively in females. Little is known about the functionality of the band heterotopia, in terms of both physiology and pathology, in this malformation. Patients are reported to have several different types of seizures, which are usually drug resistant. Interictal EEG findings are known to correlate with the type of seizures, however less is known about the ictal EEG patterns. We present 3 female patients who were investigated at our center with video-scalp EEG monitoring, interictal single photon emission computed tomography (SPECT), functional magnetic resonance (MR) imaging (fMRI) and MR spectroscopy (MRS) besides routine MR imaging. They had several different types of seizures, and one of them reported also having circling seizures that have not been reported previously in patients with SBH. Ictal EEG recordings were remarkable for their unusual patterns of propagation. The findings in structural and functional neuroradiological investigations are discussed in light of the literature.
Event-Related Brain Potentials in Reading Disabled Children during an Inverse Serial Digit Detection Task
Authors: Gómez-Velázquez Fabiola R. , González-Garrido Andrés A. , Zarabozo Daniel , de Alba J. L. Oropeza
Published: February 2012

It has been reported that limitations in different components of working memory could underlie reading disabilities. In addition, reading-disabled (RD) children seem to perform worse when digit name processing is required. With the purpose to explore further these assumptions one inverse serial digit detection task was evaluated using event-related brain potentials in fifteen 8-year-old RD children and a control group (CG). CG obtained significantly more correct responses than RD, but had similar reaction times. The experimental task performance significantly correlated with the performance on reading tests. Difference event-related potentials showed a voltage component peaking at 160 ms over frontocentral leads (P160d) that reached significantly higher amplitude in RD group, and was interpreted as an index of the amount of neural resources involved in visual working memory load. The amplitude of P160d significantly correlated with reading speed, the backward digit span and with the experimental task performance. Present results point out that highly demanding working memory tasks reveal behavioral and electrophysiological differences in RD children with respect to healthy controls.
Validating Endophenotypes for Schizophrenia Using Statistical Modeling of Twin Data
Authors: Hall Mei-Hua , Rijsdijk Frühling
Published: February 2012

The use of endophenotypes (intermediate quantitative traits) is one strategy that may provide valuable information about the neural mechanisms underlying disease etiology and facilitate discovery of susceptibility genes. For a trait to be an appropriate endophenotype, several key features should exist. In this article we discuss validating potential electrophysiological endophenotypes for schizophrenia based on conventionally accepted criteria. We focus on applying a twin study design and model fitting techniques to evaluate whether three event-related potential paradigms (P300, P50, and MMN) meet criteria as valid endophenotypes of schizophrenia.
Appraisal of Sessional EEG Features as a Correlate of Clinical Changes in an rTMS Treatment of Depression
Authors: Price G.W. , Lee J.W. , Garvey C. , Gibson N.
Published: February 2012

Previous findings on electrophysiological features related to depression predict that these correlate with clinical assessment, and potentially act as proxy measures of state changes. We investigated selected electrophysiological features to evaluate their utility as proxies for clinical ratings and in prediction of treatment outcome.

Using typical EEG data from an repetitive transcranial magnetic stimulation (rTMS) treatment regime, we analyzed individual alpha power and frequency, and asymmetry index from 39 patients with treatment resistant depression. The prognostic utility of these features was assessed in terms of group identification, correlation with clinical rating, or association with the time course of treatment.

There was no significant group difference in asymmetry between depression patients and normal and clinical controls. Background alpha was significantly less in depression patients than controls, with the schizophrenia group midway between. There was no significant group change in asymmetry index or background alpha activity with treatment. There was a weak effect of rTMS over each session on alpha power and on asymmetry, but in the opposite direction to predictions. There was weak evidence of predicted correlation between asymmetry index change and clinical rating change, as well as in final scores that was opposite to predictions. Finally there was no strong evidence that either feature fitted a linear or more complex model of daily treatment.

In conclusion, the findings are not sufficient, under our current clinical treatment regime, to support the use of background alpha activity or frontal asymmetry as proxies for clinical assessment. Several findings, however, provide support for further research in this direction.
Evaluating the Relationship between Long Interval Cortical Inhibition, Working Memory and Gamma Band Activity in the Dorsolateral Prefrontal Cortex
Authors: Daskalakis Zafiris J. , Farzan Faranak , Barr Mera S. , Rusjan Pablo M. , Favalli Gabriela , Levinson Andrea J. , Fitzgerald Paul B.
Published: February 2012

Recent reports have demonstrated that long interval cortical inhibition (LICI) can be indexed in the dorsolateral prefrontal cortex (DLPFC) in healthy controls. LICI is a neurophysiology process indexed using transcranial magnetic stimulation and is closely associated with cortical GABAB receptor mediated inhibitory neurotransmission. Several previous studies have also reported that gamma band activity represents a neurophysiological process that is mediated, in part, through GABAergic inhibitory neurotransmission and may subserve several cognitive operations including working memory (WM) in the DLPFC. The intension of the current study, therefore, was to directly evaluate the relationship between these neurophysiological processes in healthy subjects.

Eleven right-handed healthy subjects participated in this experiment in which gamma band activity was measured through simultaneous recording of electroencephalography (EEG) during the N-back task, a cognitive task designed to index WM. LICI was recorded through EEG from the left DLFPC, left motor cortex and through EMG of peripheral hand muscles in a separate session according to previously published methods.

There was no evidence for a relationship in the DLPFC between LICI and gamma band activity elicited during the N-back task, though there was a significant relationship between LICI and performance on the 3-back condition, the N-back condition of greatest difficulty.

In conclusion these data provide evidence to suggest that in the DLPFC, there is no direct relationship between GABAB receptor mediated inhibitory neurotransmission and gamma band activity. However, our data does suggest that LICI was related to 3-back performance providing evidence implicating DLPFC GABAergic inhibitory neurotransmission in WM performance.
Temporospatial Characterization of Brain Oscillations (TSCBO) Associated with Subprocesses of Verbal Working Memory in Schizophrenia
Authors: Stephane Massoud , Ince Nuri F. , Leuthold Arthur , Pellizzer Giuseppe , Tewfik Ahmed H. , Surerus Christa , Kuskowski Michael , McClannahan Kate
Published: February 2012

The studies of the neural correlates of verbal working memory in schizophrenia are somewhat inconsistent. This could be related to experimental paradigms that engage differentially working memory components or methodological limitations in terms of characterization of brain activity.

Magnetoencephalographic recordings were obtained on 10 schizophrenia patients and 11 healthy controls while performing a modified Sternberg paradigm to investigate subprocesses of verbal working memory. A new method for temporospatial characterization of brain oscillations was applied to whole head recordings and a 1–48 Hz frequency range.

Patients differed from controls in event-related synchronization/desynchronization (ERS/ERD) patterns during the encode phase, the mid-maintain phase, and the end of the maintain phase. During the encode phase, patients did not show 1–4 Hz ERS in the left anterior frontal and left parietal lobes. In the mid-maintain phase, the left anterior frontal and left parietal lobes 1–4 Hz ERS, and the bilateral occipital lobes 8–32 Hz ERS were not observed in patients. At the end of the maintain phase, patients did not exhibit 12–48 Hz ERD in the left frontal and parietal lobes. The behavioral data showed reduced primacy effect

In schizophrenia, the encode and maintain subprocesses were associated with less ERS and less ERD, respectively. These ERS/ERD abnormalities had specificity in terms of frequency and spatial location. Less ERD reflects reduced complexity of the neural activity, while reduced ERS reflects failure of the neural systems to resume idle state. The impaired primacy effect appears related to specific ERS/ERD patterns in the encode and maintain phases.
Alpha Coma Pattern in a Child
Authors: Bragatti J. A. , Mattos A. M. , Bastos H. , Riesgo R. S.
Published: February 2012

Alpha coma, an EEG pattern characterized by diffuse or widespread rhythmic activity in the alpha frequency band, is typically recorded in patients with profound coma and is frequently associated with severe neurological conditions. The most common etiologic factors of this pattern are hypoxic-ischemic encephalopathy, encephalitis, head trauma, metabolic disorders, and drug overdose. Reports of alpha coma pattern in children are relatively common. Clinical significance, both in children and adults, is variable, and highly dependent on etiology. The objective of this article is to report a clinical case of alpha coma pattern in a child with neuroblastoma. The EEG pattern was recorded during the evolution of treatment, secondary to complicating septic encephalopathy. The alpha coma pattern was replaced by a normal trace following a favorable outcome after sepsis resolution.
Recent EEG and ERP Findings in Substance Abusers
Authors: Ceballos Natalie A. , Bauer Lance O. , Houston Rebecca J.
Published: February 2012

Research on electroencephalographic (EEG) correlates of substance use has a long history. The present paper provides a review of recent studies −2001 to the present—with a focus on EEG findings in human participants characterized by a history of chronic substance use, abuse or dependence. In some areas (e.g., alcohol and cocaine dependence), the field has attempted to build upon earlier work by incorporating different methodologies or pursuing research questions of a transdisciplinary nature. New areas of inquiry, such as the investigation of EEG differences among users of ecstasy (MDMA) and methamphetamine, have emerged, primarily as a result of an alarming rise in popularity of these drugs.
What is the Source of the EEG?
Authors: Kirschstein Timo , Köhling Rüdiger
Published: February 2012

Neurons in the human cortex generally process their information by means of electrical signals and thus enable the electrical recording of their activity, the electroencephalogram (EEG). Due to their unique orientation with their long apical dendrites perpendicular to the cortical surface, large cortical pyramidal neurons in deep cortical layers play a major role in the generation of the EEG. Specific and non-specific thalamic nuclei, as well as distant cortical areas, terminate on these apical dendrites and form myriads of excitatory and inhibitory afferents. The release of excitatory and inhibitory neurotransmitters by these fibers activates specific postsynaptic receptors and generates excitatory and inhibitory postsynaptic potentials, respectively. By electrotonic spread of postsynaptic potentials along the apical dendrites and equivalent capacitive currents, they become electrical dipoles. Positive or negative deflections are generated by both excitatory and inhibitory afferents, depending on the location of these synapses on the apical dendrites. Negative (upward) deflections are due to superficial excitatory or deep inhibitory inputs, whereas positive (downward) deflections represent deep excitatory or superficial inhibitory inputs.