bluuebunny/crossref_metadata_2025_split huggingface dataset:
Somatosensory responses during selective spatial attention: The N120‐to‐N140 trasition
Authors: GARCÍA‐LARREA LUIS , LUKASZEWICZ ANNE‐CLAIRE , MAUGUIÈRE FRANÇOIS 
Published: February 2007

AbstractThe somatosensory evoked potential negative components in the 100–150‐ms range were studied under conditions where attention was directed either toward or away from the probe stimulus. An N120 component, not sensitive to spatial attention, appeared in all conditions, including the no‐task condition. Its distribution was consistent with an origin in the second somatic area. A later N140 response, not recorded in neutral conditions, was highly sensitive to spatial attention and reached its maximum to stimulation of the attended hand; its behavior was consistent with that of a processing negativity. The N140 was bilaterally distributed, but the hemisphere contralateral to stimulation appeared to be involved earlier than the ipsilateral one. Although the exogenous N120 may be influenced by somatosensory awareness and perhaps tactile recognition, the N140 appears linked to the spatial components of attention and results from the activation of several areas in both hemispheres.
Time course and mechanisms of decreased plasma volume during acute psychological stress and postural change in humans
Authors: PATTERSON STEPHEN M. , KRANTZ DAVID S. , JOCHUM SANDRA 
Published: February 2007

AbstractIn this study, we examined the effects of psychological stress on calculated plasma volume, the relationship of these changes to changes in hematologic factors, and the time course of plasma volume changes. Plasma volume changes were assessed using mass densitometry techniques, which measured changes in blood and plasma density. Hematologic and hemodynamic variables were assessed in 40 healthy men and women during a mental arithmetic (math) or benign reading task and during postural change (standing). Results indicated that math and posture change produced a significant decrease in plasma volume (ps < .001) and increases in blood pressure (ps < .001), blood and plasma density (ps < .001), and total plasma protein (p < .001). Correlations were observed between plasma volume changes and changes in systolic (r= .55, p < .0001), diastolic (r= .61, p < .0001), and mean (r= .65, p < .0001) arterial pressure during math; plasma volume and blood pressure returned to baseline within 12 min following the math task. These results suggest that an important mechanism for stress‐induced decreases in plasma volume is increased blood pressure leading to increased fluid shifts from the vasculature into the interstitial spaces.
Effects of sound intensity on a midlatency evoked response to repeated auditory stimuli in schizophrenic and normal subjects
Authors: GRIFFITH JAY , HOFFER LEE D. , ADLER LAWRENCE E. , ZERBE GARY O. , FREEDMAN ROBERT 
Published: February 2007

AbstractInhibitory gating of response to repeated stimuli is demonstrated by several event‐related potentials, including the auditory P50 wave. The present study examined the effects of variation in sound intensity on this phenomenon in schizophrenics and normal subjects. Paired clicks, 500 ms apart, were presented 50 dB above threshold to 10 normal subjects and 10 schizophrenics. The normal subjects demonstrated significantly more decrement of response to the second stimulus than did the schizophrenics. When the sounds were noticeably louder(70 dB above threshold), no such difference was observed. Rather, both groups had similarly diminished gating of response. A significant difference between schizophrenics and normal subjects was also observed when the sounds were 30 dB above threshold, but the difference was smaller than that at 50 dB. At any stimulus intensity, concomitant eye movements led to loss of gating of P50 in the normal subjects.
Preparation for action: An ERP study about two tasks provoking variability in response speed
Authors: WASCHER EDMUND , VERLEGER ROLF , JASKOWSKI PIOTR , WAUSCHKUHN BERND 
Published: February 2007

AbstractThis study focused on the covariation of response speed and event‐related potentials during response preparation and on whether these variations can be brought under experimental control. Two S1‐S2 choice response tasks with temporal uncertainty were conducted. In Experiment I, S1 was 100% informative. Fast subjects showed larger P3s with S1 than slow subjects. The terminal CNV (tCNV) increased intraindividually with response speed. In Experiment 2.50% of S1s were uninformative and the visual display was designed to attract more attention. Effects of information were found on P3 amplitude, on the topography of tCNV, and on the temporal distribution of response times. Interindividual differences disappeared in Experiment 2. The results suggest that group differences in Experiment 1 were due to different strategies of allocating visual attention. Interindividual variations of strategy showed a pattern of effects different from intraindividual variations of efficiency.
N200 in the flanker task as a neurobehavioral tool for investigating executive control
Authors: KOPP BRUNO , RIST FRED , MATTLER UWE 
Published: February 2007

AbstractEvent‐related potentials were recorded in a flanker task using arrowheads pointing to the left or to the right as targets and as congruent or incongruent flanker stimuli using squares as neutral flanker stimuli. The onset of the flanker stimuli preceded that of the target stimuli byt 100 ms. Lateralized readiness potentials showed response activation below execution threshold in correspondence to the information conveyed by the flanker stimuli. Exclusively, the incongruent flanker condition provoked a N2c, which evolved closely synchronized to the erroneous response. Graded response analyses separating incongruent trials with weak, medium, and strong incorrect response activation revealed that the N2c amplitude covaried with the magnitude of the erroneous response. The N2c in the incongruent compatibility condition of the flanker task thus corresponds to the avoidance of inappropriate responses, possibly reflecting the inhibition of automatically but erroneously primed responses. The results are compatible with studies of error correction, suggesting that efference monitoring is a constituent of executive control.
Stimulus novelty and significance in electrodermal orienting responses: The effects of adding versus deleting stimulus components
Authors: GATI ITAMAR , BEN‐SHAKHAR GERSHON , AVNI‐LIBERTY SHARON 
Published: February 2007

AbstractSeveral aspects of a feature‐matching theory formulated to account for the roles of stimulus novelty and significance in determining orienting responses (ORs) were examined. Stimulus significance and stimulus novelty were independently manipulated, and the electrodermal component of the OR was measured while sequences of compound pictorial or verbal stimuli were presented. Each sequence included a test stimulus, which was either significant or neutral, and was preceded by several standard control stimuli. Novelty was manipulated by either adding or deleting components from the standard stimuli, and significance was defined within the framework of the guilty knowledge paradigm. A change in the number of components of both verbal and pictorial test stimuli affected OR magnitude for significant but not for neutral test stimuli. Similar ORs were obtained regardless of the direction of stimulus change.
Saccades to moving targets in schizophrenia: Evidence for normal posterior cortex functioning
Authors: CLEMENTZ BRETT A. 
Published: February 2007

AbstractPeople diagnosed with schizophrenia have abnormalities of smooth pursuit eye movement initiation that could be attributable to dysfunction of posterior cortical areas and/or the smooth pursuit regions of frontal cortex. To evaluate whether schizophrenia patients' pursuit initiation performance is most consistent with pre‐ or postrolandic neuropathology, 25 schizophrenia patients and 25 nonpsychiatric individuals were presented step‐ramp stimuli moving either away from or toward the fovea. Schizophrenia and nonpsychiatric individuals did not differ on position error of saccades to moving targets, suggesting that the schizophrenia patients did not have general difficulty with motion perception. During the initial 100 ms of smooth pursuit, however, schizophrenia patients had significantly slower eye velocities than did nonpsychiatric individuals. These results suggest that schizophrenia patients'smooth pursuit abnormalities are not associated with neuropathology of posterior cortical areas.
Phase‐sensitive interaction of cardiac and respiratory timing in humans
Authors: JENNINGS J. RICHARD , MCKNIGHT J. DANIEL , VAN DER MOLEN MAURITS 
Published: February 2007

AbstractWe asked whether the heart rate response to respiratory change varied as a function of timing within the cardiac cycle. Respiratory and electrocardiographic data were collected from seven men and seven women during three weekly sessions under conditions of normal and visually paced breathing. Results revealed that, when inspiration began sooner than 500 ms before the subsequent heart beat, inspiration had little effect on the subsequent interbeat interval. However, the timing of the subsequent beat was accelerated when inspiration began later than 450 ms before this heart beat. Similar relationships were observed for expiratory onset. Results were not attributable to volitional control or rate of breathing. The modulation of respiratory sinus arrhythmia by the timing of respiratory events in the cardiac cycle has implications for the role of vagal control in the synchronization of heart rate with respiratory and behavioral actions.
Neurophysiological correlates of mental arithmetic
Authors: PAULI PAUL , LUTZENBERGER WERNER , BIRBAUMER NIELS , RICKARD TIMOTHY C. , BOURNE LYLE E. 
Published: February 2007

AbstractThirteen subjects were extensively trained on nine multiplication problems varying in difficulty. Practice was associated with a reaction time speed up and an attenuation of the problem size effect. The introduction of previously unpracticed problems led to a performance rebound to pretraining levels, indicating practice specificity. The event‐related potentials were characterized by a late positive complex, followed by a positive slow wave. Offset latency of positive slow wave and preresponse amplitude at parietal electrodes showed practice specificity effects that systematically changed with practice and problem size, indicating an association with the load imposed on working memory. The peak of the late positive complex probably reflects task learning or adaptation effects because it was attenuated by practice predominantly at frontal electrodes, showed no practice specificity, and was not affected by problem size.
Bradycardia during baroreflex stimulation and active or passive stressor tasks: Cardiorespiratory fitness and hostility
Authors: GRAHAM RALPH E. , ZEICHNER AMOS , PEACOCK LELON J. , DISHMAN ROD K. 
Published: February 2007

AbstractWe examined whether the resting bradycardia associated with cardiorespiratory fitness extends to lowered heart rate (HR) and mean arterial pressure during novel passive or active laboratory stressors and to a longer heart period during stimulation of the carotid‐cardiac vagal baroreflex, independently of the Type A behavior pattern (TABP) and hostility. Forty‐four normotensive Caucasian men (18–35 years of age) completed the Structured Interview for TABP, the Cook‐Medley Hostility Scale, and a peak oxygen uptake (Vo2peak) test. Vo2peakwas inversely related to HR prior to, during, and after each stressor and was positively related to heart period during baroreflex testing. Hostility was inversely related to heart period during baroreflex testing. TABP had no effects. Our findings indicate that cardiorespiratory fitness and low hostility are independently associated with a bradycardia during stimulation of the carotid‐cardiac baroreflex, consistent with a possible enhancement of cardiac vagal tone.
Prepulse effects on the photic eyeblink reflex: Evidence for startle‐dazzle theory
Authors: BURKE JASON , HACKLEY STEVEN A. 
Published: February 2007

AbstractWeak visual prestimulation effects on the early (R50, 50–80 ms) and late (R80, 80–200 ms) components of the eyeblink response to bright light flashes were studied in 16 normal individuals. At a lead time of 120 ms, R50 was inhibited relative to no‐prepulse control trials, whereas R80 was facilitated. According to the proposed startle‐dazzle theory, luminance onset transients trigger an initial response, R50, that is functionally related to startle. Sustained stimulation then activates prolonged eyelid (R80) and pupil responses, which serve to minimize retinal bleaching. Although the sensitivity of the photic blink reflex to attention is controversial, R50 latency showed a pattern suggestive of inhibition of return (Posner & Cohen, 1984, Attention and performance, Vol. X, pp. 531–556, Hillsdale, NJ: Erlbaum). Analyses in a patient with unilateral occipital lobe damage supported previous evidence that inhibition by a visual prepulse requires neocortex, but facilitation does not.
Temporal prominence of auditory evoked potentials (N1 wave) in 4‐8‐year‐old children
Authors: BRUNEAU N. , ROUX S. , GUÉRIN P. , BARTHÉLÉMY C. , LELORD G. 
Published: February 2007

AbstractCortical auditory evoked potentials (N1 wave) were studied in 24 adults (12 men, 12 women) and 20 children (12 boys, 8 girls; age: 4‐8 years). In adults, this wave was recorded with maximal amplitude at frontocentral sites, peaking at about 100 ms poststimulation, whereas in children the auditory response displayed maximal amplitude at the midtemporal sites, with a positive wave at about 100 ms and a large negative wave at approximately 170 ms. Moreover, the modulatory effects of intensity on N1 amplitude were prominent at frontocentral sites in adults and at temporal sites in children. Frontocentral negative response was also recorded in children but was smaller in amplitude and longer in peak latency (around 140 ms) than in adults; responses were of greater amplitude at the frontal site than at the vertex before 6 years of age, whereas the reverse was more often found after this age. These data suggest great differences with age in the neural generators contributing to auditory evoked potentials recorded in the N1 latency range.
An assessment of the discomfort associated with the use of rose bengal 1% eyedrops on the normal human eye: a comparison with saline 0.9% and a topical ocular anaesthetic
Authors: Doughty Michael J. , Lee Carole‐Ann , Ritchie Seana , Naase Taher 
Published: February 2007

AbstractPurpose:  To assess the time‐dependent changes in ocular comfort following unilateral instillation of preservative‐free rose bengal 1% eyedrops when compared with saline 0.9% or proxymetacaine 0.5%.Methods:  A total of 61 subjects, aged between 19 and 77 years, were asked to complete an ocular symptoms questionnaire, and then to indicate the comfort level for each eye on a 100‐point visual analogue scale (VAS). A single drop of rose bengal was instilled in one eye (left or right) and a drop of saline or anaesthetic instilled in the other eye. The VAS assessments were repeated at an average of 4 and 7 min later.Results:  The instillation of rose bengal eyedrops produced an initial average reduction in comfort of 39.8 points, as compared with a reduction of 11.5 points following the anaesthetic and a reduction of 3.4 points for saline. However, the responses to rose bengal were highly variable, ranging from reductions of 1.5 to 84.6 points. In most subjects, some recovery had occurred within 6–8 min, but the comfort scores averaged 27.8 points below baseline levels prior to rose bengal. Slightly greater discomfort was noted by older subjects and those with darker irides.Conclusions:  This study confirms that the use of rose bengal eyedrops can elicit a sensation of discomfort, but that this adverse reaction does not last very long. Based on the initial kinetics of recovery from discomfort, it is estimated that this should last no longer than 10–15 min (at least for those without significant ocular surface disease).
Yield and uptake of fertilizer nitrogen by direct‐drilled winter barley growing on a chalk soil
Authors: Christian D.G. , Crees R. , Dowdell R.J. 
Published: February 2007

Abstract. This paper reports the growth and yield of grain and the utilization of fertilizer nitrogen applied on either one or two occasions in spring to a crop of winter barley established by direct drilling on a chalk soil in southern England. Nitrogen, as ammonium nitrate, was applied at rates of 0 to 140 kg N ha−1 in a range of proportions on two occasions (March and April 1981); nitrogen‐15 was used to facilitate study of the nitrogen utilization by the crop.When sampled before the second top‐dressing in April, the greatest number of tillers were found on plants treated with 70 and 100 kg N ha−1 in March. The total above ground dry matter production at harvest was greatest when the split nitrogen dressing totalled more than 100 kg N ha−1, although the apparent efficiency of nitrogen usage (kg DM per kg N applied) was greatest when 60 kg N ha−1 was divided equally between the two application dates. Grain yield was heaviest (6.471 ha−1) at the largest rate of nitrogen applied (140 kg N ha−1); the lightest yield from the nitrogen treated crops was recorded from 100 kg N ha−1 applied as a single dressing in April that stimulated shoot production and decreased individual grain weight. The recovery in grain and straw of labelled fertilizer nitrogen applied only in March averaged 42.2% and was 49.8% when the nitrogen was applied only in April. The recovery of nitrogen applied in both March and April at the total rate of 100 kg N ha−1 but split 30/70 or 70/30 was 44.5% and 42.5% respectively. Non‐fertilizer sources of nitrogen contributed 60.7–71.7% of the total nitrogen uptake by the crop at harvest.
Nitrogen losses from the field: denitrification and leaching in intensive winter cereal production in relation to tillage method of a clay soil
Authors: Colbourn P. 
Published: February 2007

Abstract. Losses of soil and fertilizer nitrogen by leaching and denitritication from a clay soil in southern England have been measured over four years. Nitrate losses in drainage water from direct‐drilled land averaged 20–30 kg N ha ‘a’ with wide seasonal variation. Ploughing and conventional cultivations increased this loss. Denitritication from direct‐drilled land averaged 5–10 kg N ha ‘a’ with wide seasonal variation. Ploughing and drainage both diminished denitritication losses but cultivation had the greater effect. These nitrogen losses occurred mainly in autumn and spring.Nitrogen losses, in drainage water or by denitritication after spring fertilizer applications, were related to the rainfall in the 28 days following top dressing. Approximately 40 mm rain was needed to cause a loss of 10% of the nitrogen applied but in practice losses were quite variable.
Soil degradation and management under intensive sugarcane cultivation in North Queensland
Authors: Wood A.W. 
Published: February 2007

Abstract. Sugarcane yields in the Herbert Valley in North Queensland have been declining over the past 15 years. Better yields are obtained where crops are grown on previously unused land. Soils under cane are more compacted, more acid, contain less organic matter and are lower in cation exchange capacity and exchangeable cations. These differences reflect soil degradation caused by intensive cultivation.Contributing factors to the degradation of soils include soil compaction and structural breakdown occurring during harvest and cultivation operations, losses of organic matter due to burning of crop residues and acidification of soils due to large applications of nitrogen fertilizers.Soil management practices should aim to increase soil organic matter levels, provide a more favourable biological environment, reduce physical damage to soils during harvesting and cultivation, reduce soil acidity and improve the effectiveness of fertilizing practices.
Principles of land appraisal and land use planning within the European Community
Authors: Verheye W.H. 
Published: February 2007

Abstract. In the European Community (EC) a change towards more market‐oriented land use planning is required because of surplus stocks of cereals and dairy products, while at the same time other agricultural goods have to be imported. The implementation of such a policy has to be based on a scientifically sound and objective inventory of the physical potential of the EC as a whole.Principles of such a physical land assessment are explained, using the concepts of the FAO‐Framework for Land Evaluation and the Agro‐ecological Zone Approach, but adapted to European conditions. The conclusions arrived at through this procedure lead to different alternatives and scenarios, and hence provide valuable background information for future land use planning.
Subsoil strength and yield of vegetable crops
Authors: Stone D.A. 
Published: February 2007

Abstract. In a field experiment over two years, broad beans (Vicia faba), cabbage (Brassica oleracea var. capitata), leeks (Allium porrum) and red beet (Beta vulgaris var. esculenta) were grown on a sandy clay loam soil in which a range of bulk densities and penetration resistances had been established by (1) thorough loosening to 0.9 m by trenching, (2) artificially compacting with tractor wheelings or (3) leaving unloosened.Loosening the soil substantially increased, and compacting it decreased, yields of all four crops. The mean penetration resistance of the subsoil at field capacity correlated negatively with dry matter production. The relationship was broadly similar for all crops and years, showing a decrease in dry matter production of about 1 t ha‐1 per 0.5 MPa increase in resistance over the range examined.
Estimating losses in the yield of winter wheat as a result of drought, in England and Wales
Authors: Weir A.H. 
Published: February 2007

Abstract. A simple model for droughtiness, when linked to the distribution of soil types in England and Wales, is potentially valuable for estimating drought‐induced losses of yield in winter wheat at either particular places or in larger areas of the country. The model defines droughtiness, D, in terms of the soil water extractable by the crop, AP, and the adjusted potential moisture deficit, MD: D=AP−MD.The model should represent well the growth of actual crops of winter wheat if AP, which is based on laboratory measurements, accurately simulates the extraction of soil water by roots, if MD represents the cumulative transpiration of water by wheat crops by mid‐July, and if the latter is an appropriate date for testing the effect of drought on grain growth. These three assumptions have been investigated using measurements of artificially draughted crops of winter wheat.The results indicate that mid‐July is a good choice for a single date and MD a good representation of the water requirement of a wheat crop that has been draughted to the point where yield is beginning to be affected. For the deep‐rooting crops studied, AP underestimates the soil water extracted by the crop, and therefore overestimates the susceptibility of the soil to droughtIf average MD values are replaced by means and a standard deviation the resulting normal distribution of D‐values can be used to assess the probability that drought will limit yields. When applied to a droughtiness map of England and Wales with AP‐values used for the soils the model predicts that the soils growing wheat will be susceptible to drought in 16–84 years out of every 100. Our results suggest, however, that this probably applies to shallow rooting or diseased crops and that for deep‐rooting, healthy crops the drought risk is much less serious.