bluuebunny/crossref_metadata_2025_split huggingface dataset:
Haemodynamic Adjustments to Mental Stress in Normotensives and Subjects with Mildly Elevated Blood Pressure
Authors: Carroll Douglas , Harris Michael G. , Cross Gwen 
Published: February 2007

ABSTRACTCardiac output, heart rate, stroke volume, pre‐ejection period, total peripheral resistance, systolic and diastolic blood pressure, and oxygen consumption were monitored or derived in young men with mildly elevated casual blood pressures and unambiguously normotensive control subjects before, during, and after exposure to a mental arithmetic stress. Measurements were also taken while subjects underwent graded dynamic exercise. This permitted cardiac output—oxygen consumption regression equations to be calculated and, as a consequence, cardiac output during mental stress to be represented as additional cardiac output. Systolic and diastolic blood pressure were higher during all phases of the study in the mildly elevated blood pressure group. An overall groups effect during the mental stress phase of the experiment was observed for cardiac output and pre‐ejection period, and the effect for stroke volume was close to significance. Significant Groups X Periods interactions were found for cardiac output and additional cardiac output, and the heart rate effect was nearly significant. Post‐hoc comparisons here indicated that, in the main, group differences in these cardiac variables were more evident during the mental arithmetic stress than during the pre‐ and post‐task baseline periods. Total peripheral resistance did not differ reliably between groups and the cardiac effects were specific to the mental stress phase of the study.
Electrodermal Lability and Myocardial Reactivity to Stress
Authors: Kelsey Robert M. 
Published: February 2007

ABSTRACTThe relationship between electrodermal lability and myocardial reactivity to stress was examined in male undergraduates, who were classified as electrodermally labile (n=19) or stabile (n=19) based on the frequency of nonspecific skin conductance responses at rest. Heart rate, pre‐ejection period, cardiac output, and skin conductance responses were recorded at rest, during task instructions, and during two mental arithmetic tasks that varied in level of difficulty. As predicted, labiles exhibited greater myocardial reactivity to the task instructions and the tasks than did stabiles, with more persistent group differences emerging for pre‐ejection period and cardiac output than for heart rate. The group differences did not vary as a function of task difficulty, but did decline over time. These results support a positive relationship between electrodermal lability and beta‐adrenergic myocardial reactivity to stress, particularly under conditions of task novelty or uncertainty, and suggest that electrodermal lability is related fundamentally to arousal and reactivity processes.
Selective Effects of Alcohol on Electrodermal Indices of Orienting Reflexes to Signal and Nonsignal Stimuli
Authors: Lyvers Michael , Maltzman Irving 
Published: February 2007

ABSTRACTEffects of a moderate dose of alcohol on the electrodermal orienting reflexes evoked by novel signal, novel nonsignal, and common nonsignal stimuli were assessed. Social drinkers were randomly assigned to the four cells of a balanced placebo design, with 10 males and 10 females per group. They drank a beverage consisting of either tonic water only, or tonic water plus enough vodka to raise blood alcohol levels to approximately .05%. Following drinking and absorption periods, spontaneous and evoked skin conductance responses (SCRs) were recorded. Subjects pressed a footpedal whenever they heard an odd stimulus tone in a series. Alcohol increased the frequency of spontaneous SCRs, increased the number of incorrect pedal‐press responses, and selectively enhanced SCRs evoked by the signal tone, p<.05. Results are interpreted in terms of a hypothesized selective effect of alcohol on frontal cortical inhibitory functions.
Graphical and Statistical Techniques for Cardiac Cycle Time (Phase) Dependent Changes in Interbeat Interval
Authors: Jennings J. Richard , van der Molen Maurits W. , Somsen Riek J.M. , Ridderinkhof K. Richard 
Published: February 2007

ABSTRACTCardiac cycle time effects refer to the relative lengthening or shortening of a single cardiac cycle as a function of when in the cycle brief sensorimotor events occur. These effects may provide short‐latency measures of cardiac sensitivity to psychological events. Conventional representations have, however, failed to clearly separate changes in interbeat interval due to cycle time—i.e., phase dependent changes—from other types of change. This paper advocates a particular technique of plotting to solve these representation problems. Heartbeat timing is represented in real time and in the context of beats both preceding and following the event of interest. The plot, a phase‐sensitive plot, conceptualizes phase‐sensitive (cardiac cycle time) effects as a change in linear or higher order trend. Thus, an adaptation of trend analysis is proposed as an efficient statistical analysis that follows directly from the proposed representational technique.
The Startle Eyeblink Response to Low Intensity Acoustic Stimuli
Authors: Blumenthal Terry D. , Goode Christopher T. 
Published: February 2007

ABSTRACTFour experiments were conducted to investigate the acoustic startle response to stimuli of low intensities. Eyeblink responses (integrated EMG from orbicularis oculi) were measured from male and female college students. Experiment 1 compared tone and noise stimuli varying in intensity (50 and 60 dB(A) SPL), with noise stimuli producing greater response amplitude and probability than tone stimuli. Experiment 2 was designed to investigate temporal summation of low intensity stimuli using single and paired 70dB(A) SPL broadband noises, and an onset‐to‐onset interval between the brief stimuli in a pair equal to the duration of the single stimuli. Increasing the duration of single stimuli resulted in larger responses, illustrating temporal summation. Experiment 3 used 60 and 70 dB(A) SPL broadband noise varying in rise/fall time, with faster‐rising stimuli producing larger responses, and more intense stimuli producing larger and more probable responding. Experiment 4 employed the startle modification paradigm using 60 and 70 dB(A) SPL broadband noises as startle stimuli and a 50dB(A) SPL tone as a prepulse. Response amplitude and probability to both 60 and 70 dB(A) SPL stimuli were significantly inhibited by the 50dB(A) SPL prepulse. These studies show that the acoustic startle response is more sensitive than previously thought, and the elicitation of startle by low intensity stimuli argues against the limitation of the startle reflex as a high intensity phenomenon. These findings can increase the application of this response system by showing that startle stimuli need not be of high intensity, because reliable and differential startle can be elicited and modified at relatively low stimulus intensities.
Effects of Inter‐Item Lag on Word Repetition: An Event‐Related Potential Study
Authors: Karayanidis Frini , Andrews Sally , Ward Philip B. , McConaghy Neil 
Published: February 2007

ABSTRACTPrior exposure to a word can greatly facilitate performance to subsequent presentations of that word. ERP studies have shown that this facilitation is associated with an attenuation of a negative peak normally occurring around 400 ms poststimulus. Recent studies have interpreted this repetition effect as reflecting either lexical access or episodic memory mechanisms. However, there is now increasing evidence that neither of the above mechanisms alone can fully account for repetition effects. The present experiment recorded ERPs to immediate and delayed word repetition during a lexical decision task in order to investigate the time‐course of ERP repetition effects. Immediate repetition was found to produce greater response facilitation than delayed repetition. The ERP waveforms of both immediate and delayed word repetition diverged from that of initial word presentation at approximately 300 ms poststimulus. The waveforms for repeated words separated around 400 ms poststimulus with immediate repetition showing a more rapid resolution of negativity and earlier late positivity than delayed repetition. It is suggested that the negativity may reflect processes involved in the overall activation contributing to word recognition, whereas the late positivity may be related to the repetition of stimulus categorization and decision processes.
An ERP‐Based, Control‐Question Lie Detector Analog: Algorithms for Discriminating Effects Within Individuals' Average Waveforms
Authors: Rosenfeld J. Peter , Angell Andrea , Johnson Mary , Qian Jia‐HE 
Published: February 2007

ABSTRACTTwo experimental, P3‐based analog control question tests were run. In both, guilty subjects were presented with a set of seven phrases describing antisocial acts of which they were innocent, plus one phrase describing a guilty act (the analog relevant question), and one act to which a “yes” response (yes‐target stimulus) was required to assure attention. Innocent subjects (run only in Experiment 1) saw all innocent acts plus the yes‐target act. Thus nine acts were seen by guilty and innocent subjects. In both experiments, all subjects had to selectively review their guilty acts privately. Also in both experiments, all subjects were especially questioned about four acts of which guilty subjects were known to be innocent of all but one, and of which innocent subjects were known to be innocent of all. (These falsely accused acts were regarded as control question analogs.) In Experiment 1, the private review and rehearsal took place on the same day as the main test. In Experiment 2, one subgroup (delay‐only) of guilty subjects was run as in Experiment 1, except that the private review‐rehearsal was separated from the main run by 7–14 days. Another subgroup (delay‐rehearsal) of guilty subjects was run just as was the subgroup delay‐only, except that the delay‐rehearsal subgroup additionally received a non‐selective additional interrogation/rehearsal on the delayed main run day. Parietally maximal P3 responses were obtained to yes‐target items in all groups. In Experiment 1, only in the guilty group was the relevant‐minus‐control P3 amplitude difference significant. In Experiment 2, the difference was significant only in the delay‐rehearsal subgroup. A four‐step algorithm (involving relevant‐control amplitude differences and relevant target vs. control‐target cross‐correlations) was used to assess effects within individuals. In Experiment 1, 12 of 13 guilty subjects and 13 of 15 innocent subjects were correctly diagnosed. In Experiment 2, 3 of 8 delay‐only subjects and 7 of 8 delay‐rehearsal subjects were correctly diagnosed. In Experiment 2, the relevant‐minus‐control group P3 amplitude difference was significant in the delay‐rehearsal but not in the delay‐only subgroup. The results suggest that temporally proximal, non‐selective rehearsal procedures are sufficient to activate personal knowledge of a salient (oddball). P3‐generating stimulus phrase, and that even selective rehearsal of guilty acts is not sufficient without temporal proximity.
Weak Sensory Stimuli Induce a Phase Sensitive Bradycardia
Authors: Jennings J. Richard , Molenvan der Maurits W. , Somsen Rlek J.M. , Brock Kay 
Published: February 2007

ABSTRACTWe attempted to demonstrate that significant perceptual stimuli would induce different degrees of heart rate deceleration depending on when (phase) in the cardiac cycle they occurred. Relative to previous work, we concurrently examined a number of factors that might alter the amplitude of such a cardiac cycle time effect. Stimulus intensity and presence or absence of a speeded response were manipulated. Liminal stimuli and a perceptual rather than motor set were expected to maximize any cardiac cycle time effect. Respiratory phase, length of average interbeat interval, and number of trials were also investigated. Twenty‐four college aged, male volunteers were randomly separated into equal groups receiving instructions either to judge which of two weak visual stimuli occurred or to execute a speeded, discriminative response to the stimuli. Discriminative stimuli were presented at either 0, 150, 250, 350, or 500 ms after the R‐wave of the electrocardiogram. Stimuli were presented with an intensity that had yielded either 63% or 90% correct detections in a prior psychophysical assessment. A phase dependent deceleration occurred after both intensities of stimuli. Poststimulus deceleration was greater for stimuli in early to mid cycle as suggested by earlier work. As expected, this result was clear when the stimuli were presented during the expiratory phase of respiration. Neither perceptual/motor set nor stimulus intensity altered the phase sensitive deceleration. Thus, phase sensitive deceleration was confirmed using demanding sensory stimuli and an improved representational technique.Integrative SummaryBy controlling response speed and graphically separating anticipatory and stimulus induced effects, we have demonstrated primary bradycardia. Poststimulus deceleration was a decreasing function of time of stimulus presentation within the cardiac cycle. As expected, primary bradycardia was present during the expiratory phase, but not the inspiratory phase of respiration. Manipulations designed to enhance perceptual analysis altered performance but failed to significantly alter the cardiac response. Thus, we were able to produce a robust primary bradycardia, but were unable to alter the strength of primary bradycardia by manipulation of perceptual variables.
Cortical Activity Elicited by Changes in Auditory Stimuli: Different Sources for the Magnetic N1OOm and Mismatch Responses
Authors: Sams Mikko , Kaukoranta Elina , Hämäläinen Matti , Näätanen Risto 
Published: February 2007

ABSTRACTMagnetic responses to frequent and infrequent auditory stimuli, all presented in the same stimulus block in randomized order, were recorded. The standard stimuli, comprising 90% of all the stimuli, were 100‐ms, 1000 Hz, 90dB sinusoidal tone bursts. There were three deviant tones, each presented at a probability of 3.3%, which differed from the standard tone on one dimension only: frequency deviant (1500 Hz), intensity deviant (67dB SPL), or duration deviant (50 ms). All mismatch fields, i.e., responses elicited by different deviants, as well as N100m to the standards and deviants, could be explained by neural activity in the supratemporal auditory cortex. The source of N100m to standards and deviants was significantly posterior to the sources for the three different mismatch fields. The mean locations of the equivalent dipoles for the different mismatch fields did not differ significantly from each other, but some differences were found for individual subjects.
A Major Effect of Recording Site on Measurement of Electrodermal Activity
Authors: Scerbo Angela Scarpa , Freedman Lauren Weinstock , Raine Adrian , Dawson Michael E. , Venables Peter H. 
Published: February 2007

ABSTRACTAlthough the medial phalanx has been recommended as the preferred site for recording skin conductance activity, a review of articles published in Psychophysiology indicates that a large minority (34%) of studies employ the distal phalanx. Informal observations also suggest that the distal site may be more reactive than the medial site. This study formally tests this observation by recording skin conductance from both medial and distal phalanges. Twenty‐four right‐handed subjects (12 male, 12 female) were exposed to a series of 10 orienting and defensive stimuli. Electrodes were placed on the fore and middle fingers of each hand, with distal sites used on one hand and medial sites on the other for each subject. Skin conductance amplitudes were 3.5 times larger at distal than medial sites (p<.002), while skin conductance levels were 2.08 times larger at distal sites (p<.0005). A significant Site × Stimulus interaction (p<.025) indicated that the distal site was more sensitive to habituation over trials and to increases in skin conductance amplitudes with increasing stimulus intensity than the medial site. On the basis of these findings it is recommended that distal sites be used in preference to medial sites in the recording of skin conductance activity.
Cardiovascular Reactivity in Type A and B Males to Mental Arithmetic and Aerobic Exercise at an Equivalent Oxygen Uptake
Authors: Delistraty Damon A. , Greene William A. , Carlberg Karen A. , Raver Karen K. 
Published: February 2007

ABSTRACTCardiovascular hyperreactivity (i.e., response in excess of metabolic requirements) to psychologyical stress has been implicated in the development of coronary heart disease. The purpose of this study was to evaluate cardiovascular hyperreactivity to psychological stress in Type A and B subjects. Fifteen Type A and 15 Type B young men performed mental arithmetic and cycle ergometry tasks. Linear regressions were calculated for each dependent variable during exercise with oxygen uptake serving as the independent variable. All cardiovascular variables were significantly correlated (p<0001) with oxygen uptake during exercise. The regression equations obtained during exercise were then used to predict the value of each cardiovascular variable at the oxygen uptake level obtained during mental arithmetic for each person. Repeated measures ANOVA compared responses observed during arithmetic with responses predicted from exercise at an equivalent oxygen uptake in Type A and B subjects. Heart rate, total peripheral resistance, and mean arterial pressure were significantly greater (p<0001) and stroke volume was significantly lower (p<.0002) during arithmetic than during exercise, while Heather index, cardiac output, and arteriovenous oxygen difference did not differ significantly. No significant differences were found between Type A and B males. Results demonstrated that cardiovascular hyperreactivity was equally robust across Type A and B subjects.
Can Echoic Memory Store Two Traces Simultaneously? A Study of Event‐Related Brain Potentials
Authors: Winkler István , Paavilainen Petri , Näätänen Risto 
Published: February 2007

ABSTRACTThe mismatch negativity, a component of the event‐related brain potential elicited by infrequent deviants in sequences of auditory stimuli, is presumably generated by an automatic mismatch process in a mechanism that compares the current stimulus to the trace of the previous one. The present study addressed the possible simultaneous existence of two such traces. Two equiprobable (45% each) frequent stimuli (“standards”), one of 600 Hz and the other of 700 Hz, were presented together with an infrequent (10%), “deviant” stimulus which was of differnet frequency in different blocks. These deviants elicited a mismatch negativity, though a smaller one than that obtained in corresponding blocks with only one standard stimulus. Two aspects of the present results from the blocks with two standard stimuli implicate two parallel stimulus traces in these blocks: 1) deviants elicited a mismatch negativity (MMN) of approximately the same amplitude when preceded by sequences of four identical standards as when preceded by sequences of four stimuli containing both standards; 2) in contrast to the one‐standard condition, the magnitude of stimulus deviance did not affect the MMN component elicited by the different deviants.
Symptom‐Specific Psychophysiological Responses in Chronic Pain Patients.
Authors: Flor Herta , Birbaumer Niels , Schugens Markus M. , Lutzenberger Werner 
Published: February 2007

ABSTRACTSymptom‐specific psychophysiologiocal responding was assessed in 20 chronic back pain patients, 20 patients suffering from temporomandibular pain and dysfunction, and 20 matched healthy controls. Surface EMG from the lower and upper back, the masseter, and the biceps muscles, and heart rate and skin conductance level were continuously recorded during adaptation, resting baseline, and stressful and neutral imagery phases. Univariate and multivariate analyses of variance were performed on raw data as well as data corrected for autocorrelation. The results showed significantly higher EMG reactivity which was lateralized to the left side at the patients site of pain but not distal sites. This hyperreactivity was observed only during stressful imagery. The healthy controls displayed a significantly higher response in heart rate, but skin conductance level was not significantly different. The results are interpreted as indicative of idiosyncratic muscular response patterns to personally relevant situations at the site of pain in patients suffering from chronic muscular pain.
Temporal stability of task‐induced cardiovascular, adrenergic, and psychological responses: The effects of race and hypertension
Authors: MILLS PAUL J. , BERRY CHARLES C. , DIMSDALE JOEL E. , NELESEN RICHARD A. , ZIEGLER MICHAEL G. 
Published: February 2007

AbstractThis study examined the test‐retest reliability of task‐induced responses of blood pressure, heart rate, norepinephrine, epinephrine, anger, and anxiety in 98 black and white normotensive and hypertensive individuals. Subjects completed three laboratory tasks (standing, mental arithmetic, and cold pressor) on two occasions 10 days apart. For all subjects, all baseline and test‐retest correlation coefficients were significant (rs = .23–.71; median = .58). Baseline‐adjusted (residual scores) reactivity test‐retest correlation coefficients were consistently smaller (rs = .02–.55; median = .36). In contrast to the white hypertensives, white normotensives, and black normotensives, the black hypertensives showed no significant baseline‐adjusted test‐retest correlation coefficients (rs =−.21–.40; median = .12). Epinephrine responses revealed a significant session by race interaction; blacks had 20% higher mean values and whites had 10% lower mean values upon retesting. The data suggest that race and hypertension may interact to affect the temporal stability of task‐induced responses to stressors.
Age‐related changes in scalp topography to novel and target stimuli
Authors: FRIEDMAN DAVID , SIMPSON GREGORY , HAMBERGER MARLA 
Published: February 2007

AbstractEvent‐related brain potentials (ERPs) were recorded from young, middle‐aged, and older adults to infrequent target and novel stimuli during a version of the oddball paradigm. Analyses of scalp distribution suggested that the shift to a more frontally oriented topography with increasing age was confined to the P3 component (as compared to N1 and P2) elicited by both target and novel stimuli. This first demonstration of an age‐related shift in the scalp distribution of the novelty P3 elicited by auditory stimuli was associated with an age‐related increase in the false‐alarm rate to novel stimuli. These age‐associated differences in scalp distribution and false‐alarm rate are consistent with a change in frontal lobe activity with increasing age.
An evaluation of the automaticity of sensory processing using event‐related potentials and brain‐stem reflexes
Authors: HACKLEY STEVEN A. 
Published: February 2007

AbstractSelective attention effects on reflexes and evoked potentials are reviewed with the aim of evaluating three theories regarding sensory automaticity. (a) Theperipheral‐gating theory, which assumes that ignored stimuli can be filtered out soon after transduction, was tentatively rejected because neither auditory‐nerve nor retinal potentials are reliably affected by attention. (b) At the other extreme, the assumption that sensory analyses are obligatory and cannot benefit from attentional resources (i.e.,strong‐automaticity theory) was also rejected, because longer latency componets were found to be modifiable by attention. (c) Anintermediate theoryprovides the best fit to present electrophysiological data. The earliest sensory analyses are assumed to be strongly automatic and then, at forebrain levels, there is a transition from strong to weak automaticity (i.e., analyses are obligatory but modifiable by attention). This transition can begin as early as about 15 ms for audition and about 80 ms for vision.