bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiovascular and Metabolic Activity at Rest and During Psychological and Physical Challenge in Normotensives and Subjects With Mildly Elevated Blood Pressure
Authors: Sims Jane , Carroll Douglas 
Published: February 2007

ABSTRACTHeart rate, systolic and diastolic blood pressure, and respiratory and metabolic activity were recorded prior to and during mental arithmetic and a video game task in 20 young men with mildly elevated casual systolic blood pressures. Twenty‐five unambiguously normotensive young men were tested under the same protocol. For pretask baseline physiological activity, group differences emerged for all cardiovascular and metabolic variables; thus the elevated blood pressure group displayed not only higher resting cardiovascular levels than normotensive subjects, but higher levels of metabolic activity too. With regard to change in physiological activity from rest to task, the group with mildly elevated blood pressure showed reliably larger increases in heart rate to the mental arithmetic task than the normotensive subjects. These effects, however, were not paralleled by group differences in metabolic activity increase. Physiological measures were also taken prior to and during graded dynamic exercise. The subsequent calculation of individual heart rate‐oxygen consumption exercise regression lines allowed the comparison of actual and predicted heart rates during psychological challenge. The subjects with mildly elevated blood pressure displayed significantly greater discrepancies between actual and predicted heart rate values than normotensives during the psychological tasks in general and menta1 arithmetic in particular. Group differences in physiological activity during exercise largely reflected the pattern seen at rest. A possible exception here was systolic blood pressure. Not only were systolic blood pressure levels higher throughout the exercise phase for mildly elevated blood pressure subjects, but this group evidenced more of an increase from rest to exercise than the normotensives.
Psychophysiological Reactivity in Cardiac Transplant Recipients
Authors: Sloan Richard P. , Shapiro Peter A. , Gorman Jack M. 
Published: February 2007

ABSTRACTTo assess the contribution of the heart's autonomic innervation to reactivity to psychological stressors, hemodynamic responsiveness of the denervated human heart was examined in two studies. In Study 1, cardiac output measured by thermodilution. heart rate, and systolic and diastolic blood pressure responses to a 4‐min mental arithmetic task were studied in 7 cardiac transplant patients during routine post‐transplant cardiac catheterization. In Study II, 6 cardiac transplant patients, 5 normal controls, and 5 renal transplant patients participated in a 78‐min psychophysiological stress protocol during which heart rate, systolic and diastolic pressure, and cardiac output (measured noninvasively by impedance cardiography) as well as serum epinephrine and norepinephrine were measured at baseline and while subjects performed mental arithmetic and reaction time tasks.In Study I, transplant patients showed significant increases, relative to baseline, in heart rate, systolic blood pressure, and cardiac output in response to mental arithmetic. The diastolic blood pressure response was marginally significant. In Study II, mental arithmetic produced significant reactivity in systolic blood pressure and marginally significant increases in heart rate and diastolic blood pressure in cardiac transplant patients. Reaction time produced only marginally significant diastolic blood pressure reactivity. Hemodynamic reactivity of the cardiac transplant group generally was lower than that of the two innervated groups, which generally were similar to each other.Although the small number of subjects makes conclusions tentative, these data suggest that: 1) Cardiac transplant patients are capable of significant reactivity to psychological stressors despite the absence of innervation of the heart, and 2) reactivity to these stressors is diminished relative to innervated control subjects. In the absence of cardiac innervation, reactivity is due to the vascular system and cardiac effects mediated by humoral factors.
Cross‐Modal Selective Attention Effects on Retinal, Myogenic, Brainstem, and Cerebral Evoked Potentials
Authors: Hackley Steven A. , Woldorff Marty , Hillyard Steven A. 
Published: February 2007

ABSTRACTShort latency evoked potentials were recorded during a cross‐modal selective attention task to evaluate recent proposals that sensory transmission in the peripheral auditory and visual pathways can be modified selectively by centrifugal mechanisms in humans. Twenty young adult subjects attended in turn to either left‐ear tones or right‐field flashes presented in a randomized sequence, in order to detect infrequent, lower‐intensity targets. Attention‐related enhancement of longer‐latency components, including the visual P105 and the auditory N1/Nd waves and T‐complex, showed that subjects were able to adopt a selective sensory set toward either modality. Neither the auditory evoked brainstem potentials nor the early visual components (electroretinogram, occipito‐temporal N40, P50, N70 waves) were significantly affected by attention. Measures of retinal B‐waves were significantly reduced in amplitude when attention was directed to the flashes, but concurrent recordings of eyelid electromyographic activity and the electro‐oculogram indicated that this effect may have resulted from contamination of the retinal recordings by blink microreflex activity. A trend toward greater positivity in the 15–50 ms latency range for auditory evoked potentials to attended tones was observed. These results provide further evidence that the earliest levels of sensory transmission are unaffected by cross‐modal selective attention, but that longer latency exogenous and endogenous potentials are enhanced to stimuli in the attended modality.
Event‐Related Potential Indices of Selective Attention and Cortical Lateralization in Schizophrenia
Authors: Michie Patricia T. , Fox Allison M. , Ward Philip B. , Catts Stanley V. , McConaghy Neil 
Published: February 2007

ABSTRACTAuditory event‐related potentials (ERPs) from a multidimensional selective attention task were recorded from 10 unmedicated schizophrenic patients and 10 age‐ and sex‐matched healthy controls. Tone pip stimuli varying on the dimensions of pitch (high or low) and location (left or right ear) formed four ‘channels’ of stimuli: left low, left high, right low, and right high. The pitch difference was considerably more difficult to discriminate than the location difference. Subjects were instructed to pay attention to a designated channel and press a button whenever they detected a long‐duration, rare target tone that occurred amongst frequent short‐duration standard tones. There were a number of differences between unmedicated schizophrenics and controls in processing negativity elicited by standard tones. There was no evidence of hierarchical processing of stimulus dimensions in the early processing negativity component, and the late frontal component was virtually absent in schizophrenics. Furthermore, there was evidence that in schizophrenics the processing of the location dimension was delayed for standard tones having the same pitch as the target. The P300 component to attended target tones was substantially reduced in schizophrenics over parietal sites but there was no difference between the two groups over frontal sites. The results are interpreted in terms of multiple attentional deficits in schizophrenics that are indicative of a failure in the planning and execution of selective listening strategies. Such a failure may result from a dysfunction in the prefrontal regions of the brain.
Effects of Stimulus Repetition, Duration, and Rise Time on Startle Blink and Automatically Elicited P300
Authors: Putnam L. E. , Roth W. T. 
Published: February 2007

ABSTRACTIntense auditory stimuli of sudden onset evoke not only startle blinks but also an event‐related potential component resembling classic P300, even when subjects have no assigned task. To more closely examine the relationship of this P300 to startle, event‐related potentials and eyeblink were recorded from 16 young adults in three paradigms designed to produce wide variation in startle amplitude: an Habituation series of 30‐ms, 105dBA white noise bursts, a Duration paradigm which presented 105dB noise bursts for 3, 10, 30, or 90 ms, and a Rise Time paradigm which varied the rise/fall times (3, 15, 30, and 45 ms) of 110dBA, 1000‐Hz tone bursts. Subjects received two runs of each paradigm. Only on the final Duration and Rise Time runs were stimuli explicitly task relevant: on those runs subjects rated verbally, midway in each 8.4‐s interstimulus interval, the disturbingness of the prior sound.Although even the briefest noise bursts evoked parietal P300 as well as startle blink, P300 did not behave like startle, P300 habituated more slowly than did blink amplitude, was more responsive to sustained noise than were blink, N110, and P190, and most importantly, did not show the sensitivity to stimulus rise time manifested by these measures. These findings suggest that the amplitude of automatically elicited P300 is not governed by the same mechanisms as startle amplitude, but behaves more like a defense response.
Voluntary Facial Action Generates Emotion‐Specific Autonomic Nervous System Activity
Authors: Levenson Robert W. , Ekman Paul , Friesen Wallace V. 
Published: February 2007

ABSTRACTFour experiments were conducted to determine whether voluntarily produced emotional facial configurations are associated with differentiated patterns of autonomic activity, and if so, how this might be mediated. Subjects received muscle‐by‐muscle instructions and coaching to produce facial configurations for anger, disgust, fear, happiness, sadness, and surprise while heart rate, skin conductance, finger temperature, and somatic activity were monitored. Results indicated that voluntary facial activity produced significant levels of subjective experience of the associated emotion, and that autonomic distinctions among emotions: (a) were found both between negative and positive emotions and among negative emotions, (b) were consistent between group and individual subjects' data, (c) were found in both male and female subjects, (d) were found in both specialized (actors, scientists) and nonspecialized populations, (e) were stronger when the voluntary facial configurations most closely resembled actual emotional expressions, and (f) were stronger when experience of the associated emotion was reported. The capacity of voluntary facial activity to generate emotion‐specific autonomic activity: (a) did not require subjects to see facial expressions (either in a mirror or on an experimenter's face), and (b) could not be explained by differences in the difficulty of making the expressions or by differences in concomitant somatic activity.
Assessing Attentional Control of Breathing by Reaction Time
Authors: Gallego Jorge , Perruchet Pierre , Camus Jean‐Françlois 
Published: February 2007

ABSTRACTThe reaction time (RT) to an auditory stimulus was measured in 27 subjects during spontaneous breathing and during controlled breathing, which consisted of maintaining a set inspiratory duration. During spontaneous breathing, reaction times were unrelated to the time the stimulus was delivered during the breathing cycle. During controlled breathing, reaction times were longer than during spontaneous breathing. Peak reaction times were observed at the transition from inspiration to expiration. After the end of controlled breathing, reaction times gradually became shorter until they reached their initial level. The findings are discussed in terms of varying allocation of attentional resources to breathing. It is argued that probe RT methodology provides a suitable means for investigating attentional control of breathing.
Significance Testing of Difference Potentials
Authors: Guthrie Donald , Buchwald Jennifer S. 
Published: February 2007

ABSTRACTThis note provides a statistical‐graphical method for the evaluation of the statistical significance of difference potentials from a group of subjects, and for the comparison of difference potentials between two groups. A table of the lengths of statistically significant intervals for various sampling interval lengths, numbers of subjects, and autocorrelation parameters is presented.
Behavioral Modulation Patterns Fit an Animal Model of Vagus‐Cardiac Pacemaker Interactions
Authors: Somsen Riek J.M. , Molenaar Peter C.M. , Van der Molen Maurits W. , Jennings J. Richard 
Published: February 2007

ABSTRACTThe present study used a computer model of the dynamic interaction between the vagus nerve and the sinoatrial pacemaker membrane potential in the heart of the rabbit to reconstruct heart rate changes under vagal excitation conditions. We asked whether a hypothetical pattern of vagal acetylcholine (ACh) release, which was based on human heart rate results in a reaction time task, could be fit to this model. The reconstructed heart rate results showed changes that were highly consistent with experimental human heart rate changes. The model reliably reproduced effects of parameters such as intrinsic heart rate level, ACh stimulus intensity, and ACh stimulus duration. In addition, the effects of anticipatory vagal ACh release, stimulus‐induced ACh, and subsequent blocking of ACh, which usually interact in human cardiac cycle time functions, could be untangled in the reconstructed heart rate results. We concluded that the mathematical model may be useful for formulating hypotheses and constructing experimental task designs for studies of human heart rate.
Active‐Passive Coping and Skin Conductance and Heart Rate Changes
Authors: Sosnowski Tytus , Nurzynska Monika , Polec Miroslaw 
Published: February 2007

ABSTRACTSixty subjects were administered 33 tasks, selected from the Raven Progressive Matrices, in conditions that differed by type of monetary reinforcement (reward, frustration, and control group). Subjects were tested in pairs. One subject, assigned as the active one, was asked to solve a problem while the other was only a passive observer. Heart rate level and the amplitude of evoked skin conductance responses were measured. Statistical analysis detected a higher heart rate level in active versus passive subjects at the beginning stage of the experiment, as well as a faster heart rate decrease in the former versus the latter group during subsequent blocks of four tasks. Changes in skin conductance response magnitude during the ensuing task phases exhibited a descending trend in passive subjects and an ascending trend in active subjects. The monetary reinforcement manipulation was not effective. The results support a concept put forward by Fowles (1988), who maintained that tonic heart rate and skin conductance response amplitude may serve as indices of the behavioral activation system and behavioral inhibition system, respectively, as postulated by Gray's model of arousal.
P300 in Patients with Unilateral Temporal Lobectomies: The Effects of Reduced Stimulus Quality
Authors: Scheffers Marten K. , Johnson Ray , Ruchkin Daniel S. 
Published: February 2007

ABSTRACTThe effects of stimulus quality on the amplitude, peak latency, onset latency, and duration of the P300 component of the event‐related brain potential were studied in patients with either a left or a right anterior temporal lobectomy and in normal controls. Stimulus quality was reduced by adding “noise” letters to words which signalled either a left or a right hand button press. Consistent with an interpretation that stimulus quality affects the subject's degree of equivocation, P300 peak latency, reaction time, and errors were all inversely related to stimulus quality, whereas P300 amplitude was directly related to stimulus quality. There were no significant differences between normal controls and either patient group for any of the ERP parameters or reaction time. Right temporal lobectomy patients made, however, significantly more errors, particularly on the catch trials, which suggests that they did not process the stimuli as thoroughly and accurately as the subjects in the other two groups. The absence of significant group differences in either the lateral symmetry or overall P300 amplitude extends the evidence against the idea that anterior temporal lobe structures make any substantial contribution to the scalp P300 in a visual discrimination paradigm. Because of observed delays in the onset of P300 in the low‐quality stimulus condition, procedures were developed to quantify both P300 onset latency and P300 duration. Reduced stimulus quality significantly increased P300 onset latency whereas P300 duration remained unaffected, indicating that stimulus categorization must occur prior to, and not during, P300.
Exaggerated Sympathetic Nervous System Response to Extended Psychological Stress in Offspring of Hypertensives
Authors: Miller Sydney B. , Ditto Blaine 
Published: February 2007

ABSTRACTThe cardiovascular responses of 24 healthy young adult males with a parental history of hypertension and 24 males without a parental history of hypertension to an extended active‐coping psychological stressor were compared under three drug conditions: placebo, the beta 1‐blocking agent metoprolol, and the alpha 1‐blocking agent prazosin. In the placebo condition, off spring of hypertensives exhibited significantly greater heart rate, blood volume pulse, and forearm blood flow responses to the task. They also exhibited a significantly greater initial decrease in forearm vascular resistance, which, in contrast to the offspring of normotensives, was no longer significantly different from baseline levels by the end of the session. No group differences in blood pressure response were observed. Metoprolol eliminated the differences in heart rate and forearm vascular resistance responses. Prazosin eliminated the difference in blood volume pulse response and elicited a sustained group difference in forearm vascular resistance. These results implicate the sympathetic nervous system in the exaggerated cardiovascular responsivity to psychological stress in individuals with a family history of essential hypertension. They also suggest that the pattern of increasing vascular resistance in response to this stressor observed in this and other studies in this laboratory reflects alpha‐adrenergic activity and not neurohumorally independent autoregulation.
Autonomic Correlates of Illness Imagery
Authors: Brownlee Susan , Leventhal Howard , Balaban Marie 
Published: February 2007

ABSTRACTPsychophysiological responses to imagery of self‐relevant illness threats were examined for high and low extreme groups of hypervigilants and health care utilizers. Heart rate, skin conductance, and respiration were the physiological measures recorded; self‐reports of perceived illness vulnerability, negative affect, image clarity, and image realness were the psychological measures obtained. Responses to neutral, exercise, and illness threat scenes were compared. Hypervigilants showed an increased heart rate response to imagery of illness scenes, whereas all other groups returned more quickly to baseline levels. The results are similar to those reported by Lang for snake phobics. They also lend some support to Horowitz's theory of intrusive imagery, in which self‐relevant, anxiety provoking events tend to continuously intrude upon one's thoughts, and this intrusive imagery was reflected cardiovascularly. There could be several possible underlying mechanisms for these findings.
Developmental Changes in the Duration of Attention to Unfamiliar Stimuli in the Rat
Authors: Hayne Harlene , Richardson Rick , Campbell Byron A. 
Published: February 2007

ABSTRACTThe purpose of the present study was to examine developmental changes in the duration of attention to novel auditory stimuli in rats from infancy to adulthood. In all experiments, the cardiac component of the orienting reponse was used as the index of attention. In the first experiment 16‐, 23‐, 30‐, and 75‐day‐old rats were exposed to a novel auditory stimulus for 60 s. Animals of all four ages exhibited a marked decrease in heart rate in response to this stimulus. Although there were no significant effects of age on the magnitude of the cardiac response, there were dramatic developmental differences in the persistence of the response. The 16‐day‐old maintained a decrease in heart rate for the entire stimulus period, whereas heart rate returned to baseline in the 75‐day‐olds after only 40 s. The duration of the cardiac response of the 23‐and 30‐day‐olds was between these extremes.In Experiments 2A and 2B the effect of stimulus complexity on duration of the cardiac response was examined. Increasing stimulus complexity prolonged the deceleratory response in the 30‐day‐olds (Experiment 2A), and decreasing stimulus complexity decreased the duration of the cardiac response in the 16‐day‐olds (Experiment 2B).The results of these experiments were discussed in the context of Cohen's and Porges's two‐phase theories of attention. The findings demonstrate that the initial attention‐getting or reactive phase decreased substantially during development.
Blushing as a Function of Audience Size
Authors: Shearn Don , Bergman Erik , Hill Katherine , Abel Andy , Hinds Lael 
Published: February 2007

ABSTRACTAlmost no experimental analysis of blushing has been done since Darwin's observations in 1872. Forty‐eight college women watched a videotape intended to elicit blushing, and a videotape not intended to elicit blushing, but elicit physiological responses. A subject was alone, or with one or four persons present. Blushing, which was measured directly with a photoplethysmograph probe on the cheek, was greater during the blushing than nonblushing stimulation. Blushing increased as audience size increased from one to four, but not from zero to one. Audience size and kind of stimulation interacted statistically. Similar results were obtained with ear coloration, cheek temperature, and skin conductance responses, although confidence levels were lower. Cheek coloration and temperature were significantly correlated during nonblushing stimulation, and the zero and one audience conditions, but not during the four audience condition, when blushing was greatest. These results may be placed within the context of emotional effects of audience size generally, including stuttering and speech disturbance, disruption of learning, and self‐reported tension.
Reflex Modification in Psychosis‐Prone Young Adults
Authors: Simons Robert F. , Giardina Barbara D. 
Published: February 2007

ABSTRACTThe present study examined modification of the startle reflex in psychosis‐prone and normal control subjects, using a continuous pure tone prestimulus (S1) and an intense white noise startle stimulus (S2). Reflex modification conditions consisted of stimulus pairs with onset asynchronies of 60, 120, and 2000 ms with a startle‐alone condition as control. Startle was indexed by the eyeblink, which was measured by vertical electro‐oculography. Subjects were identified as psychosis‐prone by their high scores on the Perceptual Aberration or the Physical Anhedonia scales.Group differences in blink magnitude inhibition were observed between perceptual aberration and control subjects during short stimulus onset asynchronies, with perceptual aberrators showing significantly less inhibition than controls at 120 ms. No differences were evident between anhedonic and control subjects at the two short onset asynchronies nor were there any significant between‐group differences when the interval between stimuli was long (2000 ms). These results suggest that subjects with perceptual aberrations may share with schizophrenics and other schizophrenia‐spectrum subjects an underdeveloped mechanism which in normal subjects is presumed to operate during preattentive processing and functions to protect sensory information from the interfering effects of subsequent stimuli.