bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of monocular viewing on heartbeat discrimination
Authors: WEISZ JÜLIA , BALÁZS LÁSZLÓ , ÁDÁM GYÖRGY 
Published: February 2007

AbstractIn monocular viewing conditions, an activational imbalance between the cerebral hemispheres was assumed to develop, the direction of which depends on the side of the viewing eye. This assumption was based on the morphological differences between the nasal and the temporal hemiretinas and on physiological data. It was assumed that the hemisphere receiving visual information via the nasal optic fibers, that is, the hemisphere contralateral to the viewing eye, would be the more activated one. Because heart beat perception is regarded as a predominantly right hemispheric function, it was predicted that during right hemispheric activation created by left monocular viewing heartbeat discrimination performance would be better than during left hemispheric activation created by right monocular viewing. This hypothesis was tested on 30 male right‐handed university students who performed a Whitehead‐type heartbeat discrimination task while viewing only with the left or with the right eye. Heartbeat perception was more accurate when viewing with the left eye. Additionally, respiratory manipulation during heartbeat discrimination improved performance on this task.
Orienting in a defensive world: Mammalian modifications of our evolutionary heritage. A Polyvagal Theory
Authors: PORGES STEPHEN W. 
Published: February 2007

AbstractThe vagus, the 10th cranial nerve, contains pathways that contribute to the regulation of the internal viscera, including the heart. Vagal efferent fibers do not originate in a common brainstem structure. The Polyvagal Theory is introduced to explain the different functions of the two primary medullary source nuclei of the vagus: the nucleus ambiguus (NA) and the dorsal motor nucleus (DMNX). Although vagal pathways from both nuclei terminate on the sinoatrial node, it is argued that the fibers originating in NA are uniquely responsible for respiratory sinus arrhythmia (RSA). Divergent shifts in RSA and heart rate are explained by independent actions of DMNX and NA. The theory emphasizes a phylogenetic perspective and speculates that mammalian, but not reptilian, brainstem organization is characterized by a ventral vagal complex (including NA) related to processes associated with attention, motion, emotion, and communication. Various clinical disorders, such as sudden infant death syndrome and asthma, may be related to the competition between DMNX and NA.
Words and sentences: Event‐related brain potential measures
Authors: VAN PETTEN CYMA 
Published: February 2007

AbstractInteractions between sentences and the individual words that comprise them are reviewed in studies using the event‐related brain potential (ERP). Results suggest that, for ambiguous words preceded by a biasing sentence context, context is used at an early stage to constrain the relevant sense of a word rather than select among multiple active senses. A study comparing associative single‐word context and sentence‐level context also suggests that sentence context influences the earliest stage of semantic analysis, but that the ability to use sentence context effectively is more demanding of working memory than the ability to use single‐word contexts. Another indication that sentence context has a dramatic effect on single‐word processing was the observation that high‐ and low‐frequency words elicit different ERPs at the beginnings of sentences but that this effect is suppressed by a meaningful sentence context.
Enhanced psychophysiological signs of attention after angiotensin‐converting enzyme inhibition by captopril
Authors: DERAD INGE , PIETROWSKY REINHARD , DODT CHRISTOPH , FEHM HORST L. , BORN JAN 
Published: February 2007

AbstractComplementary to its essential role in the central nervous control of cardiovascular activity, the neuropeptide angiotensin 11 may regulate attentional processes. The present study evaluated central nervous, cardiovascular, and sympathetic indicators of attention after inhibition of angiotensin II synthesis by captopril (50 mg vs. placebo) in 14 men. Event‐related potentials (ERPs) and stimulus‐related electroencephalographic (EEG) activity were recorded while the subject performed an auditory oddball task. Captopril increased both the N1‐P2 component of the ERP (p < .05) and – following the first tone of the task – the EEG desynchronization in the lower alpha frequency band (p < .05). Although blood pressure remained unchanged, heart rate was lowered (p < .05) and plasma norepinephrine concentrations increased (p < .01) after captpril. The effects suggest that inhibition of angiotensin II synthesis enhances an attentional state typically present during sensory intake.
Processing of complex sounds in the human auditory cortex as revealed by magnetic brain responses
Authors: ALHO K. , TERVANIEMI M. , HUOTILAINEN M. , LAVIKAINEN J. , TIITINEN H. , ILMONIEMI R. J. , KNUUTILA J. , NÄÄTÄNEN R. 
Published: February 2007

AbstractProcessing of simple and complex sounds in the human brain was compared by recording extracranial magnetic mismatch responses (MMNm; the magnetic counterpart of the mismatch negativity, or MMN) to frequency changes in these sounds. Generator sources, modeled as equivalent current dipoles (ECDs), of MMNm responses to a change in one frequency element of complex sounds (a chord and a serial tone pattern) were located in supratemporal auditory cortex, on average, 10 mm medially to the source of an MMNm elicited by an identical frequency change in a simple tone. These results suggest that at least partially different supratemporal neuron populations are invovled in processing changes in simple and complex sounds and that sensory‐memory representations for these sounds may be located in different fields of the auditory cortex.
ERP modulations indicate the selective processing of visual stimuli as a result of transient and sustained spatial attention
Authors: Eimer Martin 
Published: February 2007

AbstractTwo experiments investigated selective processing as a result of transient and sustained visual‐spatial attention. In Experiment 1, attention was cued on a trial‐by‐trial basis and event‐related brain potentials were measured to stimuli preceded by valid, invalid, or neutral symbolic precues. Trial validity had only small effects on posterior PI and N1 components. At midline electrodes, an enhanced negativity for valid as compared with invalid trials was present, which appeared to reflect initial processing costs for invalid trials followed by an additional processing benefit for valid trials. Experiment 2 investigated whether these effects are specific for transient spatial attention by comparing transient and sustained attention conditions. No indication of early processing costs was found in the latter case.
Effects of task variables on measures of the mean onset latency of LRP depend on the scoring method
Authors: Smulders Fren T. Y. , Kenemans J. Leon , Kok Albert 
Published: February 2007

AbstractThe lateralized readiness potential (LRP) can be used to index the start of response activation, The onset of the average LRP can be computed as the latency at which the component starts to deviate significantly from zero or as the latency at which a certain proportion of its maximum amplitude is attained. The properties of both measures as estimates of the mean onset latency of the LRP were examined. Experiment I was a simulation study in which the mean onset latencies were known, Results indicated different types of bias for the two measures and greater reliability for a proportional measure. In Experiment 2, the sensitivity to bias, consistency, and linearity of both measures were evaluated in a set of empirical data. By all three criteria, a proportional onset measure was superior. It is recommended that the choice of the measure should depend on the hypothesis to he tested, so that conclusions are based on the more conservative test.
Human multiunit activity related to attention and preparatory set
Authors: KROPOTOV J. D. , ETLINGER S. C. , PONOMAREV V. A. 
Published: February 2007

AbstractThe impulse activity of 183 multiunits was recorded from the premotor cortex, the caudate nucleus, the globus pallidus, and the thalamus in 15 Parkinson's disease patients bearing inert gold electrodes implanted for diagnosis and therapy. The patients performed a task in which stimulus triplets (each consisting of two informational and one trigger stimulus) were presented. The patients initiated or inhibited actions (naming or counting) depending on the particular informational stimuli, thus allowing discrimination between different components of multiunit responses associated with attention and preparatory set and with disengagement from these states. The data indicate the existence of two overlapping circuits: one responsible for preparation for and assessment of the behavioral meaning of the stimulus and the other responsible for preparation for and performance of verbal action.
Inferential and descriptive influences on measures of respiratory sinus arrhythmia: Sampling rate, R‐wave trigger accuracy, and variance estimates
Authors: RINIOLO TODD , PORGES STEPHEN W. 
Published: February 2007

AbstractThe use of respiratory sinus arrhythmia (RSA) is dependent on several quantification factors. The statistical consequences of sampling rate, R‐wave trigger accuracy, and the data structure of RSA estimates were evaluated via simulations and simulated modifications. Simulations demonstrated that sampling rate determined the amplitude of the smallest oscillation that could be accurately described. When the amplitude of the oscillation was smaller in milliseconds than the sampling interval, all smaller oscillations, regardless of amplitude, were indiscriminately assigned a default value defined as 50% of the sampling interval. Also, reduced R‐wave peak detection accuracy was demonstrated to influence statistical analyses. The distributional characteristics of several common methods of structuring RSA estimates were investigated, and results indicated that several methods result in asymmetrical distributions. We recommend using rapid sampling rates (i.e., 1 kHz), accurate R‐wave peak detectors, and avoiding statistical trouble.
Storage of feature conjunction in transient auditor memory
Authors: GOMES HILARY , BERNSTEIN RICHARD , RITTER WALTER , JR. VAUGHANM HERBERT G. , MILLER JEFF 
Published: February 2007

AbstractThe purpose of this study was to determine whether feature conjunction are stored in transient auditory memory. The mismatch negativity (MMN), an event‐related potential that is elicited by stimuli that differ from a series of preceding stimuli was used in this endeavour. A tone that differed from the preceding series of stimuli in the conjunction of tow of its features, both present in preceding stimuli but in different combination, was found to elicit the MMN, the data are interpreted to indicate that information about the conjunction of feature is stored in the memory.
Event‐related potential correlates of interference between cognitive performance and tonic experimental pain
Authors: LORENZ JÜRGEN , BROMM BURKHART 
Published: February 2007

AbstractIn this study, we examined cognitive function during experimental pain induced by an ischemic upper‐arm tourniquet. During pain and control conditions, individuals performed a memory search task and an oddball task. Reaction time, errors, and event‐related potentials in response to task stimuli were evaluated. Pain reduced accuracy and changed the response‐type dependency of errors and the reaction time within the memory search task: false rejections but not false acceptances increased, and rejections were faster than acceptances during pain, whereas the opposite occurred during control conditions. The memory probes elicited an N275 that increased and a P300 that decreased in amplitude during pain. Pain also reduced amplitudes of P200 and P300 from the oddball task. N275 enhancement was greater in nonaffected than affected individuals, suggesting its association with focused attention that inhibited disruption by pain. P300 attenuation is interpreted as an indication that cognitive involvement in pain diminishes the attention resources allocated to a concurrent cognitive task.
The concurrent recording of electroencephalography and impedance cardiography: Effects on EEG
Authors: DALTON KIM M. , DAVIDSON RICHARD J. 
Published: February 2007

AbstractThree experiments were performed testing the effects of a variety of impedance cardiograph electrode types and recording arrangements on recorded electroencephalography (EEG) using either a monopolar single‐ear reference or a physically linked ears reference. EEG was recorded either alone or concurrently with an impedance cardiograph. When the cardiograph was recorded using a spot electrode for the top current‐inducing electrode, there was an overall decrease in power density of the EEG, and this effect was dependent on the location of the recording electrode. This effect was diminished when the top cardiograph spot electrode was replaced by a mylar‐coated neck band electrode and EEG was recorded using a monopolar, single‐ear reference. However, there tended to be an overall increase in log power density of the EEG in each frequency band below 60 Hz when less technologically advanced EEG amplifiers were used. This effect was diminished if the EEG was recorded using a physically linked ears reference. Recommendations for the concurrent recording of EEG and impedance cardiography are discussed.
Probe P3 and blinks: Two measures of affective startle modulation
Authors: SCHUPP HARALD T. , CUTHBERT BRUCE N. , BRADLEY MARGARET M. , BIRBAUMER NIELS , LANG PETER J. 
Published: February 2007

AbstractTwo concurrent measures of the evoked startlé response, the elicited blink reflex and the event‐related potential, were measured while individuals viewed pictures that varied in pleasure and arousal. Replicating previous findings, the blink response was modulated by picture pleasantness, with larger reflexes elicited in the context of viewing unpleasant versus pleasant pictures. However, the probe P3 was primarily modulated by picture arousal, with smaller P3 responses elicited when viewing affective (pleasant or unpleasant) than when viewing neutral pictures. Both modulatory effects were sustained for probes presented in a subsequent picture imagery period. These data suggest that two measurable responses to the same startle probe are differentially modified by emotional context, with blink magnitude varying with pleasure and probe P3 varying with stimulus arousal.
Localization of word and face recognition memory using topographical EEG
Authors: BURGESS A. P. , GRUZELIER J. H. 
Published: February 2007

AbstractThe aim of this study was to explore the ability of epoch‐averaged electroencephalogram (EEG) to localize cognitive functions. The EEG was recorded in healthy individuals performing a task where, on the basis of evidence from other functional brain imaging techniques, there was a high expectation of where functional changes would be expected. Topographical EEG was recorded while individuals performed recognition memory tasks for words and faces. Comparison of the acquisition and recognition phases of the experiment showed significant attenuation of alpha, betal, and beta2 in the right temporoparietal region for the faces but no significant changes for words. Left temporoparietal changes for the word task were only seen among the women. The results confirmed the validity of EEG for use in the localization of cognitive function for faces for men and women but in the case of words for the women only.
Nitrate leaching from a felled Sitka spruce plantation in Beddgelert Forest, North Wales
Authors: Stevens P.A. , Hornung M. 
Published: February 2007

Abstract. Soil water samples from five horizons in a stagnopodzol were collected regularly over a five‐year period in a Sitka spruce plantation at Beddgelert Forest, North Wales. Samples were analysed for nitrate‐N and ammonium‐N. After felling, inorganic‐N concentrations increased markedly in the C horizon, generally decreased in the surface horizons and showed little change in the E and Bs horizons. Fluxes through the C horizon increased after felling from 10 to 70 kg N ha‐1 a‐1, the latter being equivalent to leaching losses in intensive lowland agricultural systems. Trends in concentration and flux were attributed to seasonal temperature and rainfall variations.Nitrate‐N dominated the dissolved inorganic‐N, especially in the lower horizons. Nitrification was obviously active, despite the acid soil. Nitrate leaching losses occurred, even beneath the standing crop. On felling, cessation of nitrogen uptake allowed substantially more nitrate to be leached as no alternative sink was immediately available.
Autotrophic and heterotrophic mechanisms for ammonia oxidation
Authors: Wood P.M. 
Published: February 2007

Abstract. Autotrophic nitrifiers such as Nitrosomonas use ammonia mono‐oxygenase for the initial stage of ammonia oxidation. Nitrification inhibitors have this enzyme as their site of action. Their mechanisms include alternative substrates, suicide substrates and cuprous copper chelators.In heterotrophs, organic nitrogen is normally in the fully reduced state, but a few cell metabolites contain N‐O bonds. The synthesis and breakdown of such compounds provides a mechanism for heterotrophic nitrification. A non‐enzymic mechanism for nitrogen‐oxidation involves hydroxyl radicals produced by the Fenton reaction. Heterotrophic nitrification is particularly important in woodland soils, where wood‐rotting fungi use free radicals to break down lignin. Tests for a radical mechanism are described.
Asymmetric information in cattle auctions: the problem of revaccinations
Authors: Chymis Athanasios G. , James Harvey S. , Konduru Srinivasa , Pierce Vern L. , Larson Robert L. 
Published: February 2007

AbstractWe analyze the problem of asymmetric information between buyers and sellers in cattle auctions, using the problem of revaccinations as the point of departure. We present a simple model to show that if buyers do not know and cannot verify whether sellers have vaccinated their animals, then they may consider revaccination. Revaccination is only a part of the broader problem of information asymmetry that includes other quality issues and costs that can be saved, thereby affecting the welfare of both buyers and sellers. We consider structural characteristics of ranching, traditions, and consumers' preferences as well as proposals regarding third‐party certification to argue that the problem of asymmetric information in cattle auctions is a persistent one. We also argue for a comprehensive empirical study of the incidence and impacts of buyer revaccination.
Effect of Melatonin on the Human Electrocardiogram and Simple Reaction Time Responses
Authors: Wynn Vernon Thomas , Arendt Josephine 
Published: February 2007

It has been suggested that melatonin may have therapeutic potential for alleviating jet lag. In an attempt to define further the effects of low pharmacological doses of melatonin on the human body, 5 mg of melatonin was given orally to one subject in a blind experiment. The electrocardiogram (ECG) was recorded together with simple reaction time (SRT) responses over a 5‐h period after taking melatonin. The main part of the project was carried out under artificial domestic lighting conditions and involved ten evening sessions.Microprocessor analysis of the ECG of one subject clearly showed that melatonin had the effect of lengthening the RR interval, that between the peak of the P wave and the onset of the R wave, and the interval between the onset of the R wave and the peak of the T wave. A model to explain the cubic curve, which was fitted by regression analysis to the data, implies that the natural evening increase in melatonin may also increase these intervals. The results suggest that melatonin may affect both the phase and the amplitude of the observed ECG phenomenon.Analysis of more than 40,000 SRT responses to both visual and auditory stimuli implied that these responses might also be lengthened by melatonin. Frequency histograms of the responses and observations on premature and missed responses were not able to reproduce the results of other workers who found that higher doses (240 mg) of melatonin decreased the number of incorrect responses to simple reaction time tasks.
GABA‐immunoreactive intrinsic and ‐immunonegative secondary neurons in the cat pineal organ
Authors: Vigh‐Teichmann I. , Petter H. , Vigh B. 
Published: February 2007

Vigh‐Teichmann I, Petter H, Vigh B. GABA‐immunoreactive intrinsic and 4mmunonegative secondary neurons in the cat pineal organ. J Pineal Res 199 1 : 10: 18‐29.Abstract:The pineal organ of the cat was studied by postembedding gamma‐aminobutyric acid (GABA) immunocytochemistry. Two polyclonal rabbit GABA antisera were used with light microscopic peroxidase and electron microscopic immunogold techniques. A considerable number of intrinsic neurons are scattered in the proximal portion of the pineal organ. Some of the nerve cells were GABA‐immunoreactive; other neurons as well as pinealocytes and glial/ependymal cells were immunonegative. A few GABA‐immunoreactive neurons behaved like CSF‐contacting neurons by penetrating the ependymal lining of the pineal recess. GABA‐immunoreactive neurons were more frequently found in the subependymal region. Small bundles of thin immunoreactive unmyelinated and thick immunoreactive myelinated nerve fibers occurred in the proximal pineal, especially near the habenular commissure. There were synapses of various types between GABA‐immunoreactive and ‐immunonegative fibers. Myelinated immunoreactive axons seemed to loose their sheaths after entering the organ. Axon‐like processes of pinealocytes terminated on dendrites of immunonegative neurons present near the posterior and habenular commissures. The axons of these neurons were found to join the commissural fibers and may represent a pinealofugal pathway conducting information originating from pinealocytes. The pinealocytic axons forming ribbon‐containing synapses on dendrites of secondary neurons speak in favor of the sensory‐cell nature of the pinealocytes. The pinealopetal myelinated GABA‐immunoreactive axons and the intrinsic “GABA‐ergic” neurons are proposed to inhibit the action of intrapineal neurons on which the pinealocytic axons terminate.
Minireview Current methodologies for the study of pineal morphophysiology
Authors: Welsh Marcia G. 
Published: February 2007

Welsh MG. Current methodologies for the study of pineal morphophysiology. J Pineal Res 1994; 16: 113–120.AbstractLight and electron microscopes, with or without the use of immunohistochemical techniques, have been the instruments of choice for study of the pineal complex even up to recent times. Other morphological technologies have become available during the past decade that, if applied to current questions concerning pineal morphophysiology, could add considerably to our understanding of this complex system. Those technologies discussed include confocal scanning laser microscopy (in conjunction with other techniques including immunohistochemistry and three‐dimensional reconstruction), tissue culture methodologies, carbocyanine dyes (i. e., DiI), in situ hybridization, and application of microinjection methodologies. It is suggested that these technologies will be necessary for morphophysiolo‐gists to not only collaborate with molecular biologists and biochemists who study the pineal complex, but to corroborate the molecular and biochemical results of our colleagues.