bluuebunny/crossref_metadata_2025_split huggingface dataset:
On Approaches to Explaining Cardiovascular Reactivity: Toward Explanations that Explain
Authors: Furedy John J. 
Published: February 2007

ABSTRACTThe control‐system mode of analysis proposed by Pavloski for cardiovascular reactivity phenomena is a purposive or teleological form of explanation, because the explicans has purpose as the central term. The problem with such explanations is that they are circular and empty, providing only a rhetorical feeling of understanding, and absence of strong‐inference research. The S‐O‐R approach, which Pavlovski opposes, provides at least the potential for non‐circular explanations, provided that the O‐related explanatory constructs are specified in normal cause‐effect terms so that, in another context, the explicans can also serve as an explicandum, and vice‐versa. Pavloski may be right in suggesting that the evidence requires a feedback, “control‐system’ construct to account for cardiovascular reactivity phenomena (although he is far from having proved this in his paper), but such a view would need to be supplemented by (non‐purposive) control‐system explanations that really explain in the logical rather than the merely rhetorical sense of that term.
A Psychometric Study of Surface Electrode Placements for Facial Electromyographic Recording: I. The Brow and Cheek Muscle Regions
Authors: Tassinary Louis G. , Cacioppo John T. , Geen Thomas R. 
Published: February 2007

ABSTRACTDespite the burgeoning literature using facial electromyography (EMG) to study cognitive and emotional processes, the psychometric properties of facial EMG measurement have received little attention. Two experiments were conducted to assess the reliability and validity of facial EMG as a measure of specific facial actions. In Experiment 1, two recording sites in the brow region were compared for their ability to differentiate facial actions hypothesized to be due to the activation of the corrugator supercilii from facial actions presumed to be due to the activation of proximate muscles (e.g. depressor supercilii, procerus, frontalis, levator labii superioris alaeque nasi, orbicularis oculi), and four sites in the infraorbital triangle were compared for their ability to differentiate facial actions hypothesized to be due to the activation of the zygomaticus major from facial actions presumed to be due the activation of proximate muscles (e.g. zygomaticus minor, risorius, buccinator, orbicularis oculi, orbicularis oris). Fifteen subjects were instructed to pose a series of facial actions while EMG activity was sampled simultaneously at all sites. In Experiment 2, 5 subjects returned to the laboratory for a more extensive investigation of surface EMG activity over the zygomaticus major muscle region. The results of this experiment confirmed the findings of Experiment 1. Overall, the results demonstrate that certain recording sites located over specific facial muscle regions are more sensitive and valid indices of particular facial actions than other nearby sites.
Assessment of Baroreceptor Reflex Function During Mental Stress and Relaxation
Authors: Steptoe Andrew , Sawada Yukihiro 
Published: February 2007

ABSTRACTThis paper describes a method of measuring baroreceptor cardiac reflex sensitivity noninvasively from spontaneous patterns of blood pressure and interbeat interval, and the application of this technique in psychophysiology. Baroreflex function was assessed in 24 female volunteers during relaxation and performance of the cold pressor test and a non‐verbal mental arithmetic task. Blood pressure and interbeat interval were monitored continuously from the finger using the vascular unloading technique. Sequences of three or more cardiac cycles were identified over which systolic blood pressure increased progressively in conjunction with lengthening interbeat interval, or systolic blood pressure decreased as interbeat interval was reduced. The regression between systolic blood pressure and interbeat interval was computed as an index of baroreflex sensitivity. Relaxation was associated with a small prolongation of interbeat interval, whereas baroreflex sensitivity increased from 17.1 to 19.8 ms/mmHg. Baroreflex sensitivity was reduced significantly during mental arithmetic (mean 14.2 ms/mmHg) but not during the cold pressor test (mean 17.4 ms/mmHg). The difference between mental arithmetic and the cold pressor test may be related to the relative intensity of cardiac and vascular responses in the two situations. The implications of these results for the understanding of behavioural influences on haemodynamic function are discussed and the advantages of noninvasive methods are considered.
Auditory and Visual P300s in Temporal Lobectomy Patients: Evidence for Modality‐Dependent Generators
Authors: Johnson Ray 
Published: February 2007

ABSTRACTThe P300 component of the event‐related brain potential (ERP) was studied in epileptic patients with unilateral resections of medial temporal lobe areas of the brain. The patients and controls were tested in an oddball paradigm in two conditions: counting and reaction time. Both auditory and visual stimuli were used to elicit ERP activity in different blocks. Despite the reported presence of locally‐generated auditory and visual P300‐like potentials in these areas, no evidence was found of any surgically‐related hemispheric asymmetries in the scalp distribution of the P300 or Slow Wave for stimuli in either modality. Moreover, compared to normal controls, there were no significant reductions in overall P300 amplitude in the patients. The patients did show a double dissociation in their frontal ERP activity: the left temporal lobectomy patients showed apparent decreased frontal auditory P300 amplitudes but normal visual P300 amplitudes, whereas the right temporal lobectomy patients showed the opposite pattern. These results appeared to be due to the presence of a longduration slow wave rather than to alterations in P300 amplitude. These data do not support the presence of a significant contribution by a hippocampal/amygdala generator to the activity of the scalp‐recorded P300 in the oddball paradigm.Topographic comparisons on normalized amplitudes revealed significantly different scalp distributions as a function of stimulus modality, event probability, and task for both the P300 and Slow Wave components. These data indicate that the amplitude variations associated with each experimental variable are due to the activity of a separate underlying neural source. The sources of task and probability effects on P300 and Slow Wave amplitude each appeared to be modality‐independent generators. The nature of the third, modality‐related generator is less clear. These results uphold the tenets of the model of P300 amplitude proposed by Johnson (1986) and argue against the idea that the P300 is a unitary phenomenon.
Developmental Evidence for Modality‐Dependent P300 Generators: A Normative Study
Authors: Johnson Ray 
Published: February 2007

ABSTRACTThe behavior of the early and late components of the event‐related brain potential (REP) elicited by auditory and visual stimuli was studied in 40 normal females between the ages of 7 and 20. The ERPs were collected using two different tasks (i.e., count and reaction time) in an oddball paradigm. Analysis of the early component (i.e., N1, P2, N2) latencies revealed small but significant decreases with age in the visual modality but no change in the auditory modality. Except for the visual N1, early component amplitudes did not change significantly over this age range. The results showed that auditory and visual P300 latencies, but not amplitudes, changed at significantly different rates over this age range. P300 latencies in the auditory modality showed a relatively abrupt change around age 12, after which P300 latencies changed little and were essentially at their adult levels. The latencies of visual P300s showed a much smaller and more steady decrease with age. Thus visual P300 latencies were shorter than auditory P300s in young children but longer than auditory P300s in older children.Significantly different scalp distributions were found for auditory and visual P300s. Although all P300 activity was maximal over parietal scalp, visual P300s were significantly larger than auditory P300s over central and frontal scalp. The developmental differences, combined with the presence of significantly different scalp topographies for auditory and visual P300s, provide convergent evidence that P300 activity is not independent of the modality of the eliciting stimulus.
The Contingent Negative Variation in Psychopaths
Authors: Forth Adelle E. , Hare Robert D. 
Published: February 2007

ABSTRACTThere have been persistent claims that the contingent negative variation (CNV) is absent or greatly attenuated in psychopaths. However, these claims are based on a few studies with serious methodological and diagnostic problems. The present study attempted to avoid these problems. The subjects were male prison inmates divided into psychopaths and nonpsychopaths on the basis of scores on the Psychopathy Checklist. CNV was recorded while the subject performed a forewarned reaction time task with a relatively long interval (6 s) between the warning stimulus and the imperative stimulus. Motivation to perform well was ensured by having reaction times to the imperative stimulus determine how much money would be won or lost on a given trial. The early CNV of psychopaths was significantly larger than was that of the nonpsychopaths. There were no group differences in the late CNV or in reaction time. To the extent that the early CNV reflects processing of the warning stimulus and attention to task demands, the results are consistent with the hypothesis that psychopaths are proficient at focusing attention on events that interest them.
Maturation of Startle Facilitation by Sustained Prestimulation
Authors: Ornitz Edward M. , Guthrie Donald , Lane Shelly J. , Sugiyama Toshiro 
Published: February 2007

ABSTRACTThe startle response to a 104dB (SPL) 50‐ms burst of white noise was facilitated by prestimulation with a nonstartling tone sustained for 2 s prior to the startling stimulus in 3, 4, 5, and 8 year old children and young adults. Both startle amplitude and onset latency showed significantly greater facilitation in the preschool children than in the 8‐year‐olds and adults. The results of this experiment, which used a fixed prestimulation interval were compared to those of an earlier study in which the prestimulation interval was varied. The maturational changes in startle facilitation in response to the 2‐s prestimulation interval were similar in the two experiments. Hence the maturational effect on startle facilitation was independent of the uncertainty (as to when the startling stimulus would be given), which might be associated with variable prestimulation intervals. These findings suggest that the neuronal mechanisms that mediate startle facilitation undergo development during early childhood and mature about 8 years of age, and that this maturational sequence is relatively independent of attentional effects.
Posture, Place, and Mood Effects on Ambulatory Blood Pressure
Authors: Gellman Marc , Spitzer Susan , Ironson Gail , Llabre Maria , Saab Patrice , Pasin Rosemary DeCarlo , Weidler Donald J. , Schneiderman Neil 
Published: February 2007

ABSTRACTAmbulatory blood pressure was studied as a function of posture, place, and mood in 131 subjects classified according to race, gender, and hypertensive status. The effect of posture was significant and explained a substantial proportion of within‐subject variability. After controlling for posture, significant place and mood effects were observed when subjects were sitting but not when they were standing. Home vs. work differences in both systolic and diastolic blood pressure were significantly greater in Whites than in Blacks. Similar differences in systolic blood pressure were greater in mild hypertensive than in normotensive subjects. The results of this study underscore the need to control for effects of posture when interpreting ambulatory blood pressure readings.
An Evaluation of the Ensemble Averaged Impedance Cardiogram
Authors: Kelsey Robert M. , Guethlein William 
Published: February 2007

ABSTRACTThe ensemble averaged impedance cardiogram was evaluated during rest and during vocal mental arithmetic stress in samples of female (n=17) and male (n=40) undergraduates. Measures of myocardial performance determined from ensemble averaged signals were compared to those determined by simple beat‐to‐beat averaging over 60‐s and 20‐s sampling intervals. In addition, the influence of cardiac interval variability on dZ/dt amplitude measures was assessed. As expected, measures derived by the two averaging techniques corresponded closely, with correlations ranging from r=0.882 to r=1.000 for the 60‐s sampling intervals, and from r=0.726 to r=1.000 for the 20‐s sampling intervals. Inverse relationships of comparable magnitude were found between cardiac interval variability and dZ/dt amplitude measures determined by both averaging techniques, suggesting that these relationships did not result simply from artifacts introduced by the ensemble averaging technique. The results support the validity of ensemble averaging as a method for deriving impedance cardiographic measures of myocardial performance.
The Relationship Between Cardiovascular Responses in the Laboratory and in the Field
Authors: Johnston Derek W. , Anastasiades Pavlos , Wood Clive 
Published: February 2007

ABSTRACTThe psychophysiological responses to laboratory stressors are often examined because it is believed that such responses relate to responsiveness in real life situations. This belief has seldom been tested. The changes in heart rate, pulse transit time, and respiration rate produced by a variety of laboratory tasks (active and passive coping and physical exercise) were related to ambulatory measures of heart rate in 32 young men. The field measures were the difference in heart rate between the waking day and when asleep, and estimates of the variability of heart rate during the day, derived from time series analyses. Average changes in heart rate and pulse transit time during specific tasks did not relate consistently to heart rate in the field. However, an active coping index, derived from the ratio of the peak heart rate during an active coping task to the peak during physical exercise related to all the field measures of heart rate responsiveness. This index, which may relate to measures of additional heart rate and heightened sympathetic response to stress, also correlated positively with Trait Anxiety and elevated basal sympathetic arousal, as measured by skin conductance level. Measures of the cardiovascular response to a passive coping task, the cold pressor, and exercise did not relate to heart rate responses in the field. The findings suggest that heightened cardiac responsiveness in real life is exhibited by subjects who show elevated peak responses to active coping stressors specifically.
A Simple Activity Measure for Use with Ambulatory Subjects
Authors: Anastasiades Pavlos , Johnston Derek W. 
Published: February 2007

ABSTRACTA simple activity measure based on the EMG recorded from the thigh was developed to monitor the physical activity of ambulatory subjects. The performance of this activity measure was assessed during four major physical activities: running, walking, standing, and sitting. Heart rate was also monitored. The results were analysed within individuals using time series analysis. The heart rate and activity series (of consecutive 30‐s means) required similar models within individuals, and both measures differentiated among running, walking, and non‐movement. The activity measure did not discriminate between postures. This measure covaried closely with heart rate and emerged as a necessary and relatively more significant predictor of heart rate variance than knowledge of the type of physical activity the subjects were undertaking. Posture, however, did add a significant and independent contribution to heart rate variance. This activity measure appears to be a simple, reliable, and valuable method of measurement of physical activity variations in ambulatory subjects.
P300, Probability, and Interstimulus Interval
Authors: Polich John 
Published: February 2007

ABSTRACTThe relationship between target stimulus probability and interstimulus interval on the P300 (P3) component of the event‐related potential was assessed in three experiments. In each study an auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1000 Hz tones. Target stimuli were presented with a probability of either .20 or .80 in different conditions which were combined factorially with different interstimulus intervals. Experiment I presented stimuli at 2.0, 2.5, or 3.0 second intervals; Experiment 2 presented stimuli at 2.0, 3.0, or 4.0 second intervals; Experiment 3 presented stimuli at 4.0, 6.0, or 10.0 second intervals. P3 amplitude was larger for the .20 relative to the .80 target probability conditions for the shorter interstimulus intervals but not for the longer intervals. P3 latency was consistently longer for the .20 relative to the .80 target probability conditions, with generally little effect observed for interstimulus interval changes. The results suggest that interstimulus interval affects component amplitude by determining the amount of processing resources available when the P3 is produced.
Topographic Quantitative EEG in Elderly Subjects with Major Depression
Authors: Pollock V. E. , Schneider L. S. 
Published: February 2007

ABSTRACTSome previous quantitative EEG research indicates that depressed subjects show increased alpha and beta compared to controls. In this report, absolute and relative amplitude measures of topographic EEG were used to compare elderly subjects with major depression to sex and age matched control subjects. Elderly depressed subjects showed significantly higher absolute alpha amplitude than controls, but regional differences did not specifically distinguish them. Relative alpha amplitudes, and absolute and relative measures of beta, delta, and theta did not reliably distinguish depressed and control subjects. The results are discussed in the context of previous EEG research in depression and the elderly. Methodological features and the implications of these findings for state and trait dependent conceptualizations of depression are considered.
Detection of Colon Distension in Colonostomy Patients
Authors: ÁDám György , Balázs Lászlo , Vidos Tibor , Keszler Pál 
Published: February 2007

ABSTRACTInborn and learned ability to detect mild, nonpainful distension of the sygmoid colon was examined in 22 patients who underwent colonostomy one year or more before the investigation. The colon was distended by a balloon inserted 10 cm below the orifice of the artificial anus. Each subject participated in three sessions on three consecutive weeks with several experimental tasks in each session. During each task, the patient received the colon stimulus (the “signal”) 25 times randomly paired with masking auditory or annular skin stimuli (around the stoma or 15 cm medially to it). The masking (warning) stimuli were administered in series of 50, representing the “noise,” according to signal‐detection paradigms. The subjects had to indicate after each administration of the warning noise stimulus whether or not they thought the colon stimu had been presented. In all three sessions, learning tasks were included using reinforcement of successful detection trials. Seven subjects out of 22 were considered good perceivers, 9 persons were considered medium perceivers, and the remaining 6 subjects were considered poor perceivers. According to the data of the first two groups, it can be hypothesized that most patients have some inherent sensitivity of colon distension, and that learning improves this initial ability. However, the role of skin, periotneal, or interstitial receptors in colon distension detection cannot be excluded.
Individual Differences in Behaviorally Evoked Cardiovascular Response: Temporal Stability and Hemodynamic Patterning
Authors: Kasprowicz Alfred L. , Manuck Stephen B. , Malkoff Susan B. , Krantz David S. 
Published: February 2007

ABSTRACTThis study evaluates the reproducibility of individual differences in behaviorally evoked cardiovascular reactivity among 39 young adult males. Presented also are initial data describing idiosyncratic patterns of hemodynamic adjustment that may underlie pressor responses to laboratory stressors. Subjects were administered three experimental stressors (mental arithmetic, mirror tracing, and bicycle exercise) on two occasions, four weeks apart. Heart rate, blood pressure, and impedance‐derived measurements of cardiac pre‐ejection period, stroke index, cardiac index, and total peripheral resistance were obtained during baseline and task periods at each session. To index task‐induced “reactivity,” residualized (baseline‐adjusted) change scores were calculated for all variables; percentage change from baseline was also calculated for impedance‐derived hemodynamic measurements. Test‐retest (inter‐session) correlations were significant for nearly all baseline, task, and change‐score measurements. The few exceptions included diastolic blood pressure changes during mirror tracing and bicycle exercise and changes in stroke index and peripheral resistance during mental arithmetic. Although virtually all baseline and task correlations exceeded .60, reactivity indices yielded consistently lower retest correlations (significantr's = .35‐.78; medianr= .49). In subsequent analyses, subsets of individuals were identified whose reactions to mental arithmetic at the first laboratory session reflected changes in either cardiac output (CI reactors, n = 9) or total peripheral resistance (TPR reactors, n = 6), or a combination of cardiac and vascular influences (Mixed reactors, n = 8). This typology of hemodynamic response: (a) was corroborated by corresponding group differences in heart rate, pre‐ejection period, and stroke index; (b) was reproducible on retesting; and (c) showed some generalization to the mirror tracing task, though not to bicycle exercise.
Diurnal Variations of ECG Parameters During 23‐Hour Monitoring in Cardiac Patients With Ventricular Arrhythmias or Ischemic Episodes
Authors: Mytrik Michael , Brügner Georg , Fichtler Achmed 
Published: February 2007

ABSTRACTECG and physical activity (recorded with motion detectors) were continuously monitored during 23 hours in 31 male cardiac patients (81% with myocardial infarction). According to the occurrence of ventricular arrhythmias (VA) or ischemic episodes (IE), each patient was grouped in one of three diagnostic categories: neither VA nor IE, VA with or without IE, and IE only. Analysis of the ECG parameters was done beat‐by‐beat and averaged on a 1‐min basis. Results were derived from the 2‐hour means between 2 p.m. and 12 p.m.MANOVA revealed significant group differences for heart rate variability (greater for the group with VA), R‐wave amplitude (higher for the group with IE), and P‐wave amplitude (higher for the group with VA). Significant time effects were observed for all variables except QRS‐ and P‐wave durations. As may be expected, physical activity and heart rate were lower at night. Heart rate variability, PQ‐interval, PR‐segment, QT‐interval, ST‐segment, and T‐wave duration increased during the night. R‐wave amplitude also increased but the relative P‐ and T‐wave amplitudes decreased. The corrected QT‐interval, QTc, was shorter at night and the ST‐segment, J + 60‐point, S‐wave, and J‐point amplitudes were less negative. Group × Time interactions were observed for T‐wave amplitude. For this amplitude, the decrease during the night was prominent only for the VA group. The results of this study suggest that the three diagnostic groups can be differentiated by diverse ECG parameters.