Distribution by Scientific Domains

Kinds of Negativity

  • error-related negativity

  • Selected Abstracts


    METAPHILOSOPHY, Issue 5 2005
    Göran Hermerén
    Abstract: In this article I focus on some of Joseph Margolis's contributions to medical ethics. I first discuss some of Margolis's normative and metaphysical views on death and abortion, particularly in his early work Negativities, as well as some of his metaphysical assumptions. Then these views and assumptions are related to his theory of persons and, by implication, his theory of culture, set forth in a number of later works. In the course of the discussion, I call attention to some controversial issues of today, such as embryonic stem cell research and the creation of embryos for the sole purpose of research, and ask for Margolis's views on them, given his earlier contributions and assumptions. Finally, I comment on his relativism and his program for research in aesthetics and ethics. [source]

    Maternal self-efficacy beliefs, competence in parenting, and toddlers' behavior and developmental status

    Priscilla K. Coleman
    This study was designed to examine parenting self-efficacy beliefs as correlates of mothers' competence in parenting toddlers and as predictors of toddlers' behavior and development. Sixty-eight predominantly middle-class mother,toddler pairs participated in this study. Mothers completed questionnaires, toddlers were administered the Bayley Scales of Infant Development (BSID-II), and each dyad participated in the Crowell Procedure, which is designed to observe parent and toddler behaviors in a semistructured laboratory context. Although domain-general and domain-specific parenting self-efficacy beliefs were not associated with parenting competence, domain-specific beliefs were significantly related to toddlers' scores on the Mental Scale of the BSID-II and several behaviors observed during the Crowell Procedure (Affection Towards Mother, Avoidance of Mother, Compliance, Enthusiasm, and Negativity). Implications of the findings are discussed. ©2003 Michigan Association for Infant Mental Health. [source]

    The Effects of Negativity and Motivated Information Processing During a Political Campaign

    Michael F. Meffert
    This research investigated how voters select, process, are affected by, and recall political information in a dynamic campaign environment. It was hypothesized that voters' information selection, processing, and recall are subject to a negativity bias (i.e., negative information dominates over positive information), a congruency bias (i.e., positive information about the preferred candidate and negative information about the opponent candidate dominate over negative information about the preferred candidate and positive information about the opponent), and a candidate bias (i.e., information about the preferred candidate dominates over information about the opponent). Motivated by an initial candidate preference, participants were also expected to develop more polarized candidate evaluations over time. Participants were exposed to quickly changing information in the form of newspaper-style headlines on a dynamic, computer-based information board. The results generally supported negativity bias and candidate bias, whereas congruency bias was only found during information recall. At the information selection and processing stages, participants with a strong initial candidate preference showed a disproportionate preference for negative information about the preferred candidate. However, they developed more positive attitudes at the evaluation and recall stage. This finding suggests that participants were engaged in motivated information processing by counterarguing negative information about their preferred candidate. [source]

    Mismatch Negativity: No Difference Between Controls and Abstinent Alcoholics

    ALCOHOLISM, Issue 1 2004
    George Fein
    Abstract: Background: A number of studies have examined the amplitude of the mismatch negativity (MMN) evoked potential as a measure of a brain inhibitory deficit in alcoholics or those at risk for alcoholism. The current study examined MMN in alcoholics abstinent an average of 6.7 years (with a minimum of six months abstinence) compared to controls. This study examined the association of MMN with alcoholism family history density, with indices of the presence and severity of externalizing disorders (a risk-factor for alcoholism), and with alcohol use variables. Methods: Electroencephalograms were gathered on 76 subjects (38 controls, 38 abstinent alcoholics) during a nonattending mismatch negativity experiment. Measures of alcoholism family history density, disinhibited personality traits, and antisocial symptoms served as measures of risk-factors known to be associated with a genetic liability to alcoholism. Alcohol use variables were used as measures of alcoholism severity. Results: There were no differences in MMN amplitude or latency between controls and abstinent alcoholics. There also were no significant associations between MMN measures and the measures of risk for alcoholism or with the severity of alcohol use or duration of abstinence. Conclusions: The results suggest that MMN is neither affected in chronic alcoholics nor associated with alcoholism vulnerability, and thus does not reflect a trait marker of alcoholism or alcoholism risk. The current results do not address effects on MMN of acute alcohol ingestion or withdrawal from alcohol. [source]

    Attack Politics: Negativity in Presidential Campaigns Since 1960 , By Emmett H. Buell, Jr., and Lee Sigelman

    Todd L. Belt
    No abstract is available for this article. [source]

    Are regulatory problems in infancy precursors of later hyperkinetic symptoms?

    ACTA PAEDIATRICA, Issue 11 2004
    K Becker
    Aim: To examine whether regulatory problems in infancy predict later hyperkinetic symptoms in childhood and pre-adolescence. Methods: In a prospective longitudinal study of 319 children at risk of later developmental problems and psychopathology, hyperkinetic behaviour problems were assessed at the ages of 2, 4.5, 8 and 11 y by means of a standardized parent interview. Infant regulatory problems at the age of 3 mo were determined from multiple sources of information. An observational procedure was used to assess the quality of mother-infant interaction. Results: At the age of 3 mo, 17% of the infants (n= 55; 27 boys, 28 girls) suffered from multiple regulatory problems. Compared to a control group (n= 264), these children presented more hyperkinetic symptoms throughout childhood. Negativity in the mother-infant interaction and early family adversity each contributed to later hyperkinetic symptoms. When controlling for family adversity, the association between infant multiple regulatory problems and later hyperkinetic problems was rendered insignificant. Conclusions: These findings suggest that multiple regulatory problems may not be a key variable for later hyperkinetic problems. The impact of early family adversity factors clearly outweighed that of infant psychopathology on later behaviour disorder. [source]

    An educational tool for power electronics circuits

    Cetin Elmas
    Abstract In this study, an educational tool has been prepared for a shorter term and more economic education of power electronics circuits. In parallel with the improvements of semiconductor technology, the development of power electronics circuits has magnified the importance of either teorical or practical education of power electronics course. The education of power electronic circuits in laboratory is an agelong, costly piece of work. In this study, to overcome the mentioned negativities, a tool has been prepared for the education of power electronic circuits. The tool, which has been prepared on C++ Builder environment has a flexible structure and a graphical interface. It has enabled the analysis of working principles of the circuits and traceability of the system response by the help of graphics, under different conditions created by changing the values of circuit elements. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 157,165, 2010; Published online in Wiley InterScience (; DOI 10.1002/cae.20237 [source]

    Auditory and speech processing and reading development in Chinese school children: behavioural and ERP evidence

    DYSLEXIA, Issue 4 2005
    Xiangzhi Meng
    Abstract By measuring behavioural performance and event-related potentials (ERPs) this study investigated the extent to which Chinese school children's reading development is influenced by their skills in auditory, speech, and temporal processing. In Experiment 1, 102 normal school children's performance in pure tone temporal order judgment, tone frequency discrimination, temporal interval discrimination and composite tone pattern discrimination was measured. Results showed that children's auditory processing skills correlated significantly with their reading fluency, phonological awareness, word naming latency, and the number of Chinese characters learned. Regression analyses found that tone temporal order judgment, temporal interval discrimination and composite tone pattern discrimination could account for 32% of variance in phonological awareness. Controlling for the effect of phonological awareness, auditory processing measures still contributed significantly to variance in reading fluency and character naming. In Experiment 2, mismatch negativities (MMN) in event-related brain potentials were recorded from dyslexic children and the matched normal children, while these children listened passively to Chinese syllables and auditory stimuli composed of pure tones. The two groups of children did not differ in MMN to stimuli deviated in pure tone frequency and Chinese lexical tones. But dyslexic children showed smaller MMN to stimuli deviated in initial consonants or vowels of Chinese syllables and to stimuli deviated in temporal information of composite tone patterns. These results suggested that Chinese dyslexic children have deficits in auditory temporal processing as well as in linguistic processing and that auditory and temporal processing is possibly as important to reading development of children in a logographic writing system as in an alphabetic system. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Is the failure to detect stimulus deviance during sleep due to a rapid fading of sensory memory or a degradation of stimulus encoding?

    Summary The mismatch negativity (MMN) is thought to reflect the outcome of a system responsible for the detection of change in an otherwise repetitive, homogenous acoustic environment. This process depends on the storage and maintenance of a sensory representation of the frequently presented stimulus to which the deviant stimulus is compared. Few studies have been able to record the MMN in non-rapid eye movement (NREM) sleep. This pattern of results might be explained by either a rapid fading of sensory memory or an inhibition of stimulus input prior to entry into the cortical MMN generator site. The present study used a very rapid rate of presentation in an attempt to capture mismatch-related negativity prior to the fading of sensory memory. Auditory event-related potentials were recorded from 12 subjects during a single sleep period. A 1000 Hz standard stimulus was presented every 150 ms. At random, on 6.6% of the trials, the standard was changed to either a large 2000 Hz or a small 1100 Hz deviant. In wakefulness, the large deviant elicited an extended negativity that was reduced in amplitude following the presentation of the small deviant. This negativity was also apparent during REM sleep following the presentation of the large deviant. These deviant-related negativities (DRNs) were probably a composite of N1 and MMN activity. During NREM sleep (stage 2 and slow-wave sleep), only the large deviant continued to elicit a DRN. However this DRN might be overlapped by the initial activity of a component that is unique to sleep, the N350. There was little evidence of the DRN or the MMN during sleep following the presentation of the small deviant. A rapid rate of presentation, therefore, does not preserve the MMN following small deviance within sleep. It is possible that inhibition of sensory input occurs before entry into the MMN generating system in the temporal cortex. [source]

    Bereitschaftspotential and movement-related potentials: Origin, significance, and application in disorders of human movement

    MOVEMENT DISORDERS, Issue 5 2007
    James G. Colebatch MB
    Abstract The existence of a slow negative wave, the Bereitschaftspotential ("BP"), preceding voluntary movement by 1 second or more was first reported more than 40 years ago. There appears to be considerable interindividual differences, but there is general agreement that the initial negativity actually consists of two distinct phases. Uncertainty remains about many other properties and features of the response, including nomenclature, which makes the existing literature difficult to synthesize. The duration of the premovement negativity raises questions about how and when voluntary movement is initiated. Premovement negativities can also be seen before (predictably) externally paced movement, and these have similarities to the BP. Although lateralized generators exist, it is likely that the majority of the early component of the BP (BP1 or early BP), arises from the anterior supplementary motor area (SMA) and more rostral pre-SMA. The late phase of the BP (BP2 or late BP) is probably generated by activity in both the SMA proper and the contralateral motor cortex. Changes in the BP occur in several movement disorders, notably Parkinson's disease, in which the pattern is consistent with a failure of pre-SMA activation. The presence (or absence) of a clear preceding negativity can also have diagnostic importance for certain movement disorders. © 2007 Movement Disorder Society [source]

    The way of our errors: Theme and variations

    PSYCHOPHYSIOLOGY, Issue 1 2010
    Robert F. Simons
    Abstract Negative feedback, either internal or external, is a fundamental guide to human learning and performance. The neural system that underlies the monitoring of performance and the adjustment of behavior has been subject to multiple neuroimaging investigations that uniformly implicate the anterior cingulate cortex and other prefrontal structures as crucial to these executive functions. The present article describes a series of experiments that employed event-related potentials to study a variety of processes associated with internal or external feedback. Three medial-frontal negativities (error-related negativity, correct-response negativity, feedback-related negativity) are highlighted, each of which plays an important role in the monitoring and dynamic adjustment of behavior. Extensions of basic research on these ERPs to questions relevant to clinical-science are also provided. [source]

    Neural generators of ERPs linked with Necker cube reversals

    PSYCHOPHYSIOLOGY, Issue 4 2009
    Michael A. Pitts
    Abstract Multistable perception occurs when a single physical stimulus leads to two or more distinct percepts that spontaneously switch (reverse). Previous ERP studies have reported reversal negativities and late positive components associated with perceptual reversals. The goal of the current study was to localize the neural generators of the reversal ERP components in order to evaluate their correspondence with previous fMRI results and to better understand their functional significance. A Necker-type stimulus was presented for brief intervals while subjects indicated their perceptions. Local auto-regressive average source analyses and dipole modeling indicated that sources for the reversal negativity were located in inferior occipital-temporal cortex. Generators of the late positive component were estimated to reside in inferior temporal and superior parietal regions. [source]

    Are the anterior negativities to grammatical violations indexing working memory?

    PSYCHOPHYSIOLOGY, Issue 5 2005
    Manuel Martín-Loeches
    Abstract Anterior negativities obtained when a grammatical rule is violated may reflect highly automatic first-pass parsing processes, the detection of a morphosyntactic mismatch, and/or the inability to assign the incoming word to the current phrase structure. However, for some theorists these negativities rather reflect some aspect of working memory processes. Event-related brain potentials (ERPs) obtained for word category and morphosyntactic violations were directly compared with effects obtained when working memory is particularly demanded (embedding subject- or object-relative clauses), yielding a significant dissociation in terms of topography. Even though, the anterior negativities for grammatical violations vanished when relative clauses were embedded, suggesting that the processes reflected by anterior negativities related to grammatical violations and those related to working memory manipulations, even if different, are placing demands on a common pool of limited resources. [source]

    The sequential processing of visual feature conjunction mismatches in the human brain

    PSYCHOPHYSIOLOGY, Issue 1 2004
    Yuping Wang
    Abstract To clarify the brain mechanism for multifeature stimulus comparison, subjects matched the features of two serial visual stimuli in pairs. Stimulus pairs were of four categories: C,S,, color same, shape same (match); C,S+, color same, shape different (shape mismatch); C+S,, color different, shape same (color mismatch); C+S+, color different, shape different (conjunction mismatches). Subjects matched the stimuli in three different sessions according to different attention tasks: attending to color (Ac), attending to shape (As), or attending to both color and shape (Acs). A negative one-peak brain potential, N270, was elicited in all the mismatch conditions with amplitude enhanced in the task-relevant mismatch. Negative potential with two peaks, N270 and N400, appeared when attending to the conjunction mismatches concurrently. The two serial negativities in response to attended feature conjunctions might reflect the temporal different stages for processing conjunction mismatches or conflicts. [source]

    Maturation of action monitoring from adolescence to adulthood: an ERP study

    Alexandra M. Hogan
    This study investigated the development of the frontal lobe action-monitoring system from late childhood and adolescence to early adulthood using ERP markers of error processing. Error negativity (ERN) and correct response negativity (CRN) potentials were recorded while adolescents and adults (aged 12,22 years, n = 23) performed two forced-choice visual reaction time tasks of differing complexity. Significant age differences were seen for behavioural and ERP responses to complex (infrequent, incompatible) trials: adolescents elicited an error negativity of reduced magnitude compared with adults. Furthermore, in contrast to adults, adolescents showed a non-significant differentiation between response-locked ERP components elicited by correct (CRN) and error responses (ERN). Behaviourally, adolescents corrected fewer errors in incompatible trials, and with increasing age there was greater post-error slowing. In conclusion, the neural systems underlying action-monitoring continue to mature throughout the second decade of life, and are associated with increased efficiency for fast error detection and correction during complex tasks. [source]

    Links between social and linguistic processing of speech in preschool children with autism: behavioral and electrophysiological measures

    Patricia K. Kuhl
    Data on typically developing children suggest a link between social interaction and language learning, a finding of interest both to theories of language and theories of autism. In this study, we examined social and linguistic processing of speech in preschool children with autism spectrum disorder (ASD) and typically developing chronologically matched (TDCA) and mental age matched (TDMA) children. The social measure was an auditory preference test that pitted ,motherese' speech samples against non-speech analogs of the same signals. The linguistic measure was phonetic discrimination assessed with mismatch negativity (MMN), an event-related potential (ERP). As a group, children with ASD differed from controls by: (a) demonstrating a preference for the non-speech analog signals, and (b) failing to show a significant MMN in response to a syllable change. When ASD children were divided into subgroups based on auditory preference, and the ERP data reanalyzed, ASD children who preferred non-speech still failed to show an MMN, whereas ASD children who preferred motherese did not differ from the controls. The data support the hypothesis of an association between social and linguistic processing in children with ASD. [source]

    PNET-like features of synovial sarcoma of the lung: A pitfall in the cytologic diagnosis of soft-tissue tumors

    Pascale Hummel M.D.
    Abstract Fine-needle aspiration (FNA) cytology of soft-tissue tumors is evolving. As more experience is gained, we are becoming aware of potential pitfalls. We describe 2 cases of synovial sarcoma of the lung, primary and metastatic, in patients who had FNA biopsy performed on a lung mass. The cytologic smears showed extremely cellular groups of malignant small round cells, intersected by small blood vessels, with numerous loose single cells, in a background of macrophages and mature lymphocytes. The tumors displayed monomorphic cells forming rosettes and displaying occasional mitoses. A diagnosis of neuroendocrine tumor/primitive neuroepithelial tumor (PNET) was suspected. Furthermore, this suspicion was supported by immunohistochemical stains, which showed positivity for a neuroendocrine marker, Leu 7 (case 1), and for a neural marker, CD 99 (O 13 or HBA 71) (both cases); and negativity for cytokeratins (case 1). The resection specimen of case 1 had mostly tightly packed small round cells, with occasional rosettes, similar to the FNA biopsy, and focal areas composed of spindle cells, organized in a focal fibrosarcoma-like and hemangiopericytoma-like pattern. A balanced translocation between chromosomes X and 18, demonstrated by both karyotyping and fluorescent in situ hybridization (FISH), enabled us to make a diagnosis of synovial sarcoma, which was histologically classified as poorly differentiated. Case 2 was a metastatic biphasic synovial sarcoma of the arm, with a prominent epithelial component. Synovial sarcoma, when composed mainly of small round cells on cytologic smears, is a great mimicker of neuroendocrine/PNET tumors, with light microscopic and immunohistochemical overlap. Awareness of this potential pitfall may aid in preventing a misdiagnosis. Its recognition is of major concern, especially for the poorly differentiated variant, because it is associated with a worse prognosis. Diagn. Cytopathol. 24:283,288, 2001. © 2001 Wiley-Liss, Inc. [source]

    Prospective non-randomized study of preoperative concurrent platinum plus 5-fluorouracil-based chemoradiotherapy with or without paclitaxel in esophageal cancer patients: long-term follow-up

    M. Zemanova
    SUMMARY Combined modality treatment for esophageal carcinoma seems to improve survival over surgery alone. Different combinations of cytotoxic drugs have been studied to improve antitumor efficacy and limit the toxicity of chemoradiotherapy (CRT) with inconsistent results. We present a prospective study of neoadjuvant CRT with or without paclitaxel in chemotherapy schedule. One hundred seven patients (93 males, 14 females), median age 59 years (range 44,76), with operable esophageal cancer were enrolled. They received the following neoadjuvant therapy: Carboplatin, area under curve (AUC) = 6, intravenously on days 1 and 22, 5-fluorouracil (5-FU), 200 mg/m2/day, continuous infusion on days 1 to 42, radiation therapy 45 grays/25fractions/5 weeks beginning on day 1. Forty-four patients (41%) were furthermore non-randomly assigned to paclitaxel 200 mg/m2/3 h intravenously on days 1 and 22. Nutritional support from the beginning of the treatment was offered to all patients. Surgery was done within 4,8 weeks after completion of CRT, if feasible. All patients were evaluated for grade 3 plus 4 toxicities: leukopenia (28%), neutropenia (30%), anemia (6%), thrombocytopenia (31%), febrile neutropenia (6%), esophagitis (24%), nausea and vomiting (7%), pneumotoxicity (8%). Seventy-eight patients (73%) had surgery and 63 of them were completely resected. Twenty-two patients (20%) achieved pathological complete remission, and additional 20 (19%) had node-negative and esophageal wall-positive residual disease. There were 10 surgery-related deaths, mostly due to pulmonary insufficiency. Twenty-nine patients were not resected, 15 for early progression, 14 for medical reasons or patient refusal. After a median follow-up of 52 months (range 27,80), median survival of 18.0 months and 1-, 2-, 3- and 5-year survival of 56.7, 37.5, 27.0 and 21% was observed in the whole group of 107 patients. Addition of paclitaxel to carboplatin and continual infusion of FU significantly increased hematologic and non-hematologic toxicity, but treatment results as overall survival or time to progression did not differ significantly in groups with and without paclitaxel. Patients achieving pathological complete remission or nodes negativity after neoadjuvant therapy had favorable survival prognosis, whereas long-term prognosis of node positive patients was poor. Distant metastases prevailed as a cause of the treatment failure. Factors significant for survival prognosis in multivariate analysis were postoperative node negativity, performance status, and grade of dysphagia. Addition of paclitaxel to carboplatin and continual FU significantly increased hematologic and non-hematologic toxicity without influencing efficacy of the treatment. This study confirmed improved prognosis of patients after achieving negativity of nodes. Distant metastases prevailed as cause of the treatment failure. Prospectively, it is important to look for a therapeutic combination with better systemic effect. [source]

    Plasma membrane surface potential (,pm) as a determinant of ion bioavailability: A critical analysis of new and published toxicological studies and a simplified method for the computation of plant ,pm

    Thomas B. Kinraide
    Abstract Plasma membranes (PMs) are negatively charged, and this creates a negative PM surface electrical potential ,PM) that is also controlled by the ionic composition of the bathing medium. The ,PM controls the distribution of ions between the PM surface and the medium so that negative potentials increase the surface activity of cations and decrease the surface activity of anions. All cations reduce the negativity of ,PM, and these common ions are effective in the following order: Al3+ > H+ > Cu2+ > Ca2+ , Mg2+ > Na+ , K+. These ions, especially H+, Ca2+, and Mg2+, are known to reduce the uptake and biotic effectiveness of cations and to have the opposite effects on anions. Toxicologists commonly interpret the interactions between toxic cations (commonly metals) and ameliorative cations (commonly H+, Ca2+, and Mg2+) as competitions for binding sites at a PM surface ligand. The ,PM is rarely considered in this biotic ligand model, which incorporates the free ion activity model. The thesis of this article is that ,PM effects are likely to be more important to bioavailability than site-specific competition. Furthermore, ,PM effects could give the false appearance of competition even when it does not occur. The electrostatic approach can account for the bioavailability of anions, whereas the biotic ligand model cannot, and it can account for interactions among cations when competition does not occur. Finally, a simplified procedure is presented for the computation of ,PM for plants, and the possible use of ,PM in a general assessment of the bioavailability of ions is considered. [source]

    Drug injecting and syringe use in the HIV risk environment of Russian penitentiary institutions: qualitative study

    ADDICTION, Issue 12 2006
    Anya Sarang
    ABSTRACT Background Evidence highlights the prison as a high risk environment in relation to human immunodeficiency virus (HIV) and hepatitis C virus (HCV) transmsission associated with injecting drug use. Methods We undertook qualitative studies among 209 injecting drug users (IDUs) in three Russian cities: Moscow (n = 56), Volgograd (n = 83) and Barnaul in western Siberia (n = 70). Results Over three-quarters (77%) reported experience of police arrest related to their drug use, and 35% (55% of men) a history of imprisonment or detention. Findings emphasize the critical role that penitentiary institutions may play as a structural factor in the diffusion of HIV associated with drug injection in the Russian Federation. While drugs were perceived to be generally available in penitentiary institutions, sterile injection equipment was scarce and as a consequence routinely shared, including within large groups. Attempts to clean borrowed needles or syringes were inadequate, and risk reduction was severely constrained by a combination of lack of injecting equipment availability and punishment for its possession. Perceptions of relative safety were also found to be associated with assumptions of HIV negativity, resulting from a perception that all prisoners are HIV tested upon entry with those found HIV positive segregated. Conclusion This study shows an urgent need for HIV prevention interventions in the Russian penitentiary system. [source]

    Cortical auditory dysfunction in benign rolandic epilepsy

    EPILEPSIA, Issue 6 2008
    Dana F. Boatman
    Summary Purpose: To evaluate cortical auditory function, including speech recognition, in children with benign rolandic epilepsy (BRE). Methods: Fourteen children, seven patients with BRE and seven matched controls, underwent audiometric and behavioral testing, simultaneous EEG recordings, and auditory-evoked potential recordings with speech and tones. Speech recognition was tested under multiple listening conditions. Results: All participants demonstrated normal speech recognition abilities in quiet, as well as normal peripheral and subcortical auditory function. BRE patients performed significantly worse than controls when speech recognition was tested under adverse listening conditions, including background noise. Five BRE patients who were impaired on two or more tests had centrotemporal spiking on awake EEG. There were no significant group differences in the latency or amplitude of early N100 cortical responses to speech or tones. Conversely, the mismatch negativity, a preattentive index of cortical processing that is elicited passively, was absent or prolonged for speech, but not tones, in BRE patients as compared to controls. Discussion: Children with BRE demonstrated specific speech recognition impairments. Our evoked potential findings indicate that these behavioral impairments reflect dysfunction of nonprimary auditory cortex and cannot be attributed solely to attention difficulties. A possible association between auditory impairments and centrotemporal spiking (>1/min) on awake EEG was identified. The pattern of speech recognition impairments observed is a known risk factor for academic difficulties in school-age children. Our results underscore the importance of comprehensive auditory testing, using behavioral and electrophysiological measures, in children with BRE. [source]

    HEPATITIS C AND ADDICTION: Retention rate and side effects in a prospective trial on hepatitis C treatment with pegylated interferon alpha-2a and ribavirin in opioid-dependent patients

    ADDICTION BIOLOGY, Issue 2 2009
    Nina Ebner
    ABSTRACT Hepatitis C viral (HCV) infection is present in 30 to 98% of intravenous drug users. Intravenous substance abuse represents the main route of HCV transmission in industrialized countries. A multi-centre, randomized, controlled, prospective study assessed sustained virological response (SVR), adverse events such as depressive episodes and retention rate of HCV treatment in opioid-dependent patients. Stabilized, opioid-dependent patients with chronic HCV infection (genotype 2 or 3) received pegylated interferon alpha-2a in combination with ribavirin 800 mg/day (Group A) or 400 mg/day (Group B). Participants were randomized, blocked and stratified by genotype and viral load. A standardized psychiatric assessment, Beck Depression Inventory (BDI) and Van Zerssen's list of complaints were administered at each study visit. In 31 months, 300 opioid-dependent patients were screened; 190 (63.3%) were hepatitis C antibody positive. According to study protocol, out of 75 ,potential-to-treat' patients with genotype 2 or 3, 17 stable patients (22.6%) were included in the study. All participants completed the study. Significant haemoglobin decreases occurred in both Groups A (P = 0.001) and B (P = 0.011). All the patients had an end-of-treatment (week 24) HCV RNA negativity. Fifteen (88.2%) achieved SVR at week 48. Overall, 52.9% developed depressive symptoms during treatment. Because of the prompt initiation of antidepressant medication at first appearance of depressive symptoms, no severe depressive episodes occurred. Our data show a high retention rate and reliability, and good viral response for both treatments. Hepatitis C treatment in stable opioid-dependent patients was efficacious, suggesting that addiction clinics can offer antiviral therapy in combination with agonistic treatment as part of multi-disciplinary treatment. [source]

    On the positive side of error processing: error-awareness positivity revisited

    Shani Shalgi
    Abstract Performance errors are indexed in the brain even if they are not consciously registered, as demonstrated by the error-related negativity (ERN or Ne) event-related potential. It has recently been shown that another response-locked potential, the error positivity (Pe), follows the Ne, but only in those trials in which the participants consciously detect making the error (,Aware Errors'). In the present study we generalize these findings to an auditory task and investigate possible caveats in the interpretation of the Pe as an index of error awareness. In an auditory Go/No-Go error-awareness task (auditory EAT) participants pressed an additional ,fix error' button after noticing that they had made an error. As in visual tasks, the Ne was similar for aware (,fixed') and unaware (,unfixed') errors, while the Pe was enhanced only for Aware Errors. Within subjects, the Ne and Pe behaved in similar fashions for auditory and visual errors. A control condition confirmed that the awareness effect was not due to the requirement to report error awareness. These results reinforce the evidence in favor of the Pe as a correlate of conscious error processing, and imply that this process is not modality-specific. Nevertheless, single-trial analysis suggested that the Pe may be a delayed P3b related to stimulus processing rather than to response monitoring. [source]

    Neural representations of auditory input accommodate to the context in a dynamically changing acoustic environment

    Torsten Rahne
    Abstract The auditory scene is dynamic, changing from 1 min to the next as sound sources enter and leave our space. How does the brain resolve the problem of maintaining neural representations of the distinct yet changing sound sources? We used an auditory streaming paradigm to test the dynamics of multiple sound source representation, when switching between integrated and segregated sound streams. The mismatch negativity (MMN) component of event-related potentials was used as index of change detection to observe stimulus-driven modulation of the ongoing sound organization. Probe tones were presented randomly within ambiguously organized sound sequences to reveal whether the neurophysiological representation of the sounds was integrated (no MMN) or segregated (MMN). The pattern of results demonstrated context-dependent responses to a single tone that was modulated in dynamic fashion as the auditory environment rapidly changed from integrated to segregated sounds. This suggests a rapid form of auditory plasticity in which the longer-term sound context influences the current state of neural activity when it is ambiguous. These results demonstrate stimulus-driven modulation of neural activity that accommodates to the dynamically changing acoustic environment. [source]

    A neuroanatomically grounded Hebbian-learning model of attention,language interactions in the human brain

    Max Garagnani
    Abstract Meaningful familiar stimuli and senseless unknown materials lead to different patterns of brain activation. A late major neurophysiological response indexing ,sense' is the negative component of event-related potential peaking at around 400 ms (N400), an event-related potential that emerges in attention-demanding tasks and is larger for senseless materials (e.g. meaningless pseudowords) than for matched meaningful stimuli (words). However, the mismatch negativity (latency 100,250 ms), an early automatic brain response elicited under distraction, is larger to words than to pseudowords, thus exhibiting the opposite pattern to that seen for the N400. So far, no theoretical account has been able to reconcile and explain these findings by means of a single, mechanistic neural model. We implemented a neuroanatomically grounded neural network model of the left perisylvian language cortex and simulated: (i) brain processes of early language acquisition and (ii) cortical responses to familiar word and senseless pseudoword stimuli. We found that variation of the area-specific inhibition (the model correlate of attention) modulated the simulated brain response to words and pseudowords, producing either an N400- or a mismatch negativity-like response depending on the amount of inhibition (i.e. available attentional resources). Our model: (i) provides a unifying explanatory account, at cortical level, of experimental observations that, so far, had not been given a coherent interpretation within a single framework; (ii) demonstrates the viability of purely Hebbian, associative learning in a multilayered neural network architecture; and (iii) makes clear predictions on the effects of attention on latency and magnitude of event-related potentials to lexical items. Such predictions have been confirmed by recent experimental evidence. [source]

    Enhanced mismatch negativity brain response after binaural word presentation

    Tanja Endrass
    Abstract An oddball paradigm was used to investigate brain processes elicited by spoken words and pseudowords played monaurally, to the left or right ear, or simultaneously to both ears of human subjects instructed to ignore acoustic stimuli but watch a silent video film. The mismatch negativity (MMN), a neurophysiological index of the automatic activation of cortical memory traces, was calculated as the difference between the event-related potential elicited by an infrequent deviant stimulus and the event-related potential to the same item presented as a frequent standard stimulus. Consistent with earlier reports, the MMN to words was larger than that to pseudowords, possibly reflecting the existence of memory traces for spoken words. Bilateral redundant stimulus presentation led to a further increase of the MMN to words relative to both unilateral stimulation modes. This bilateral redundancy gain was absent for pseudowords. We interpret the neurophysiological manifestation of a word-specific bilateral redundancy gain as evidence for interhemispheric cooperation in the automatic access to memory traces for spoken words. Accordingly, word-related cortical networks distributed over both hemispheres allow summation of neural activity between and within hemispheres, thereby potentiating the word-related MMN. [source]

    Auditory sensory memory disorder in dyslexic adults as indexed by the mismatch negativity

    T. Kujala
    Abstract Deficient temporal discrimination and vulnerability to masking effects caused by rapidly succeeding or simultaneous sounds might be one factor underlying the phonological difficulties in dyslexia. We evaluated cortical auditory discrimination in dyslexia by recording the mismatch negativity (MMN) for a simple pitch change, for an order reversal of tone pairs, and for tone-pair order reversals, with a third tone either preceding or following the tone pairs. It was found that when an additional tone followed the pairs the MMN amplitude was attenuated, suggesting elevated backward-masking effects in the auditory cortex of dyslexic individuals. In addition, the MMN elicited by pitch change was diminished over the left hemisphere of the dyslexic individuals suggesting left hemisphere auditory dysfunction. These results suggest impaired cortical discrimination of sounds and lowered tolerance for the masking effects of rapidly following sounds in dyslexia. [source]

    Synaptic stimulation of nicotinic receptors in rat sympathetic ganglia is followed by slow activation of postsynaptic potassium or chloride conductances

    Oscar Sacchi
    Abstract Two slow currents have been described in rat sympathetic neurons during and after tetanization of the whole preganglionic input. Both effects are mediated by nicotinic receptors activated by native acetylcholine (ACh). A first current, indicated as IAHPsyn, is calcium dependent and voltage independent, and is consistent with an IAHP -type potassium current sustained by calcium ions accompanying the nicotinic synaptic current. The conductance activated by a standard synaptic train was ,,3.6 nS per neuron; it was detected in isolation in 14 out of a 52-neuron sample. A novel current, IADPsyn, was described in 42/52 of the sample as a post-tetanic inward current, which increased in amplitude with increasing membrane potential negativity and exhibited a null-point close to the holding potential and the cell momentary chloride equilibrium potential. IADPsyn developed during synaptic stimulation and decayed thereafter according to a single exponential (mean ,,= 148.5 ms) in 18 neurons or according to a two-exponential time course (, = 51.8 and 364.9 ms, respectively) in 19 different neurons. The mean peak conductance activated was ,,20 nS per neuron. IADPsyn was calcium independent, it was affected by internal and external chloride concentration, but was insensitive to specific blockers (anthracene-9-carboxylic acid, 9AC) of the chloride channels open in the resting neuron. It is suggested that gADPsyn represents a specific chloride conductance activatable by intense nicotinic stimulation; in some neurons it is even associated with single excitatory postsynaptic potentials (EPSCs). Both IAHP and IADPsyn are apparently devoted to reduce neuronal excitability during and after intense synaptic stimulation. [source]

    The structure of perceived qualities of situations

    John A. Edwards
    Situations can be seen as having attributes or qualities in much the same way as people have traits. The structure of people's perceptions of these situation qualities was explored. A comprehensive list of adjectives that might describe situations was generated, and people rated situations using samples of the words. Across several samples of words and participants and several analytic methods, four factors show up regularly (positivity, negativity, productivity, and ease of negotiation). In a second study, it was shown that these factors predict the way in which people freely sort situations. The conceptual nature of these factors and of situation qualities is discussed, with particular emphasis on how people's goals and perceived outcomes influence their perceptions of situations. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Communication, Conflict, and Commitment: Insights on the Foundations of Relationship Success from a National Survey

    FAMILY PROCESS, Issue 4 2002
    Scott M. Stanley Ph.D.
    The key relationship dynamics of communication, conflict, and commitment were investigated using data from a randomly sampled, nationwide phone survey of adults in married, engaged, and cohabiting relationships. Findings on communication and conflict generally replicated those of studies using more in depth or objective measurement strategies. Negative interaction between partners was negatively associated with numerous measures of relationship quality and positively correlated with divorce potential (thinking or talking about divorce). Withdrawal during conflict by either or both partners, thought quite common, was associated with more negativity and less positive connection in relationships. The most frequently reported issue that couples argue about in first marriages was money, and in re-marriages it was conflict about children. Overall, how couples argue was more related to divorce potential than was what they argue about, although couples who argue most about money tended to have higher levels of negative communication and conflict than other couples. Further, while the male divorce potential was more strongly linked to levels of negative interaction, the female was more strongly linked to lower positive connection in the relationship. Consistent with the commitment literature, higher reported commitment was associated with less alternative monitoring, less feeling trapped in the relationship, and greater relationship satisfaction. [source]