bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Development of Sustained Visual Attention in Infants from 14 to 26 Weeks of Age
Authors: Richards John E. 
Published: February 2007

ABSTRACTThe development of sustained visual attention was examined in infants cross‐sectionally at 14, 20, and 26 weeks of age. Heart rate, heart rate variability, and respiratory sinus arrhythmia were measured in a 5‐min baseline period. Two methods for measuring visual attention were used. The “infant control” method consisted of checkerboard presentations which were terminated when the infant looked away from them. The “interrupted stimulus” method consisted of a blinking panel in addition to the checkerboard patterns in order to attempt to actively terminate the fixation. The visual and cardiac responses during the interrupted stimulus method were more highly correlated with baseline respiratory sinus arrhythmia than were the responses during the infant control trials. The long latency heart rate responses during the interrupted stimulus trials showed a developmental change toward more mature response patterns from 14 to 26 weeks of age. It may be concluded that: 1) sustained attention, measured with the interrupted stimulus method, increases from 14 to 26 weeks of age; and 2) baseline respiratory sinus arrhythmia is correlated with sustained attention responses and their development.
Scoring Criteria for Response Latency and Habituation in Electrodermal Research: A Critique
Authors: Levinson Douglas F. , Edelberg Robert 
Published: February 2007

ABSTRACTRecent evidence, particularly in research on the skin conductance orienting response (SCOR) in schizophrenia, suggests that differences in scoring criteria may be important sources of error and variability in studies of electrodermal responses to discrete stimuli and their habituation. Although a wide variety of response latency criteria have been used in published studies, empirical evidence suggests that responses occur in a narrow and early post‐stimulus time window. Data are presented demonstrating that the intra‐subject variability of response latency is low when responses are scored within a narrow time window, but that broader time windows include more variable‐latency responses that may represent spontaneous activity. The commonly‐used criterion of three no‐response trials as an habituation endpoint may also introduce contamination by spontaneous activity; available evidence favors a two‐trials criterion. Analyses such as the ones presented here permit testing of the specificity of scoring criteria for responses elicited by experimental stimuli.
The Residual After Correcting Event‐Related Potentials for Blink Artifacts
Authors: Berg Patrick 
Published: February 2007

ABSTRACTData from an event‐related potential (ERP) study using central scalp locations on 36 subjects with an oddball paradigm were analyzed to determine which of four linear regression methods was the most effective in correcting for eyeblink artifacts. The best method was then employed to determine how well the artifact was removed from independent EEG data from 10 subjects, and from the ERP data. The error remaining after correction, the residual, is a systematic time function related to the blink. Differences between corrected and artifact‐free ERPs are explicable in terms of the residual and are a function of blink latency in the corrected ERPs. The most marked difference was a positivity on Pz of up to approximately 3 μ V occurring after the mean blink latency. These results indicate that caution is necessary when correcting data for eyeblink artifacts if blink frequency and latency are systematically related to experimental condition. The residual is probably mostly a reflection of physiological events correlated with the eyeblink.
General Autonomic Components of Motion Sickness
Authors: Cowings Patricia S. , Suter Steve , Toscano William B. , Kamiya Joe , Naifeh Karen 
Published: February 2007

ABSTRACTThis report refers to a body of investigations directed toward the examination of autonomic nervous system responses to motion sickness. Heart rate, respiration rate, finger pulse volume, and basal skin resistance were measured on 127 men and women before, during, and after exposure to a nauseogenic rotating chair test. Significant changes in all autonomic responses were observed across the tests (p<.05). Significant differences in autonomic responses among groups divided according to motion sickness susceptibility were also observed (p<.05). Results suggest that the examination of autonomic responses as an objective indicator of motion sickness malaise is warranted and may contribute to the overall understanding of the syndrome.
Phasic Cardiac Reactivity to Psychological Stress as a Function of Aerobic Fitness Level
Authors: Shulhan Donna , Scher Hal , Furedy John J. 
Published: February 2007

ABSTRACTCardiovascular adjustments to physical exertion are known to be affected by aerobic fitness level. This raises the possibility that the cardiovascular responses associated with psychological stress may also be related to aerobic fitness. This study was undertaken to determine if phasic cardiac reactivity to stress would be affected by aerobic fitness level, and to make inferences regarding the autonomic mechanisms which might mediate such an effect.Twenty‐four males were given a standard physical fitness test and then divided into high and low aerobic fitness level groups. Within two weeks of this assessment, the heart rate and electrocardiographic T‐wave amplitude responses of these subjects were monitored during the performance of hard and easy versions of a mental arithmetic task. Analysis of the heart rate data revealed no aerobic fitness level effect. There was, however, greater T‐wave amplitude attenuation in the low as compared to the high aerobic fitness level group on hard trials. This pattern of results suggests that psychologically‐elicited sympathetic cardiac reactivity is reduced by enhanced aerobic fitness level.
The Effects of Psychological and Environmental Stressors on Peristaltic Esophageal Contractions in Healthy Volunteers
Authors: Young Larry D. , Richter Joel E. , Anderson Karen O. , Bradley Laurence A. , Katz Philip O. , McElveen Lisa , Obrecht W.F. , Dalton Chris , Snyders R. Miller 
Published: February 2007

ABSTRACTThe relationship between various stressful stimulus conditions, measures of anxiety, and altered esophageal motility was investigated in mo experiments employing normal adult volunteers. In Experiment 1, subjects were administered separately I00dB continuous white noise and a cold pressor task. In Experiment 2. subjects were administered in a counterbalanced order intermittent and unpredictable bursts of 100dB white noise and a cognitive task consisting of solvable and unsolvable discrimination problems. Results of both experiments showed that the amplitudes of peristaltic esophageal contractions and levels of state anxiety self‐reports were significantly higher during periods of stress than during preceding baseline periods. Furthermore, in Experiment 2, esophageal contraction velocities and anxiety‐related behaviors were significantly greater during stress periods than during baselines. Contrary' to previous studies, few abnormal tertiary esophageal contractions were elicited by stress. The present results identify increased amplitude of the peristaltic contractions as the primary esophageal response to stress. Technological and methodological differences between this study and previous Investigations of affective disturbance among patients with chronic esophageal chest pain also are examined.
Respiratory Sinus Arrhythmia as an Index of Parasympathetic Cardiac Control During Active Coping
Authors: Grossman Paul , Svebak Sven 
Published: February 2007

ABSTRACTPsychophysiological studies concerning tonic cardiac responses to stressor tasks have tended to emphasize beta‐adrenergic effects and to neglect parasympathetic influences and sympathetic‐parasympathetic interactions. Much recent evidence indicates that both within‐ and between‐individual variations in cardiac parasympathetic heart rate (HR) control can be easily and reliably assessed by measuring the magnitude of respiratory sinus arrhythmia (RSA). Therefore, we used RSA to index cardiac vagal responses to two active coping tasks. Both tasks consisted of the same video game, in one condition with threat of shock for inferior performance, and in the other without such threat. Twenty subjects underwent both tasks (counterbalanced over subjects), plus a preceding resting baseline period. HR and RSA were continuously measured. Results suggested that cardiac parasympathetic activity was diminished from rest to task, contributing to heart rate responses. Exaggerated HR responses were also associated with extreme parasympathetic withdrawal. Furthermore, task condition X sequence of presentation interaction effects showed that threat of shock was particularly effective in elevating HR and reducing RSA when the threat was presented during the first task condition. A repeated‐measures analysis of covariance of HR, attempting to remove the effects of parasympathetic influences upon HR, suggested that sympathetic influences upon HR exceeded any reciprocal vagal effects during the threat condition for those subjects exposed to the threat task first. The findings indicate the importance of considering stress‐related parasympathetic effects upon HR as well as sympathetic‐vagal interactions.
Modification of the Acoustic Startle Reflex by a Tactile Prepulse: The Effects of Stimulus Onset Asynchrony and Prepulse Intensity
Authors: Blumenthal Terry D. , Gescheider George A. 
Published: February 2007

ABSTRACTThe present experiments were designed to assess the effects of a tactile prepulse on the acoustic startle response in human adults. Acoustic startle stimuli were presented via loudspeaker, and tactile prepulse stimuli were presented by a vibrator contactor on the thenar eminence of the right band. In Experiment 1 stimulus intensity was 20dB above each individual subject's psychophysical tactile threshold and stimulus onset asynchrony (lead time) was 50, 100, 200. or 300 ms, with a control condition in which no prepulse was presented. In Experiment 2, the same stimuli were used, except that tactile prepulse intensity was varied (−4, 0, 4, 8, 12, and 20 dB above each subject's psychophysical threshold), and lead time was constant at 200 ms. Reflex eyeblink responses were assessed from integrated periorbital etectromyographic (EMG) activity. Compared to responding in the control condition (no prepulse), a prepulse at a 50‐ms lead time facilitated responding by increasing response amplitude and decreasing latency. At a lead time of 100 ms, the amplitude increase was no longer found, but the latency decrease was still apparent, as was a decrease in response probability. At lead times of 200 and 300 ms, responding was inhibited, as shown by‐decreased response amplitude and probability. At a lead time of 200 ms. tactile prepulses as low as 8dB above threshold caused a reduction in response amplitude, but no effects of prepulse intensity on response probability or latency were found. The prepulse intensity and lead time effects shown in the present study demonstrate that the presentation of a brief, near‐threshold tactile prepulse can either facilitate or inhibit an acoustically‐elicited startle response, depending upon the temporal relationship between the two stimuli. Also, the different measures of the startle response reflect this modification in different ways.
Proximal Effects of Two and Four Hour Naps Within Extended Performance Without Sleep
Authors: Webb Wilse B. 
Published: February 2007

ABSTRACTSubjects performed on a battery of tests for 3 days and nights with minimal or no sleep. Three nap schedules were investigated: 2 hrs from 0800‐1000 following Nights 1 and 2 (morning naps); 2 hrs from 2200–2400 prior to Nights 2 and 3 (evening naps): 4 hrs from 2000–2400 prior to Night 2. There was n no‐nap control group. Measures from a 30‐min addition task and subjective measures of sleepiness were analyzed. The measures used were from approximately 2 hrs before and 2 hrs after the experimental conditions. The data show an ameliorative proximal effect of naps through at least the second night.
Thirty‐Six Hour Correspondence Between Performance and Sleepiness Cycles
Authors: Lavie P. , Gophe D. , Wollman M. 
Published: February 2007

ABSTRACTThe present work investigates the correspondence between rhythmicity in performance efficiency and sleepiness. Eight subjects kept a repeating schedule of 7 Min in bed, 13 min awake out of bed, for two 36‐hr periods. Each 36‐hr period followed 28 hrs of sleep deprivation. Periods were separated by a one‐week interval. Time in bed was subject to two experimental conditions, either attempting or resisting sleep. During each 13‐min period outside the bedroom, subjects were tested on a choice reaction time task with three levels of movement difficult). In both the attempting sleep and resisting sleep conditions, reaction time and movement lime showed marked circadian modulation, generally matching the sleepiness cycle. There was no interaction between movement difficulty and (he effects of sleep loss. There were no significant differences in total sleep between the conditions of attempting and resisting sleep; however, subjects instructed to resist sleep had slower reaction times and less stable movement times. The significance of these findings is discussed in terms of differences between attentional mechanisms and multiple processing resources. Results support a theory that the performance and sleep wake cycles are not causally related but rather, may be regulated independently.
The Effects of Piracetam Upon Visual Event‐Related Potentials in Dyslexic Children
Authors: Conners C.K. , Reader M. , Reiss A. , Caldwell J. , Caldwell L. , Adesman A. , Maver L. , Berg M. , Clymer R. , Erwin R. 
Published: February 2007

ABSTRACTTwenty‐nine dyslexic children (mean age 10 yrs) were randomly assigned to piracetam (3.3 gr/d) or matching placebo in a 36‐week double‐Mind study. Event‐related potentials (ERPs) were obtained at the end of treatment from a vigilance paradigm which required a response to letter‐matches or form‐matches. The drug group showed a significant advantage in letter‐bits compared with placebo, and a reduced variance in reaction time. The drug increased the amplitude of three factors from a principal components analysis of ERPs, and was interpreted as increasing a processing negativity when stimuli were letters. Effects upon the prestimulus baseline for letter‐hits were interpreted as faster termination of a CNV under drug for letter‐pairs. Latency of early N100 components were faster under drug, suggesting improved feature analysis. It is concluded that piracetam enhances feature analysis and increases attentional resources among dyslexics when the stimuli are recognized as having linguistic significance.
Effects of Experimentally‐Induced Sleep Fragmentation on Sleep and Sleepiness
Authors: Magee Jon , Harsh John , Badia Pietro 
Published: February 2007

ABSTRACTThe effects of two levels of sleep fragmentation on sleep and daytime sleepiness were investigated in young adult males. Experimental subjects were informed while awake that tones would be presented periodically throughout the night and that their task was to terminate the tone by taking a deep breath. Eight subjects received tones after each minute of sleep and 8 received tones after each 4 min of sleep. Control subjects (N=8) HI did not receive (ones. The subjects were tested for daytime sleepiness using the Multiple Steep latency Test. It was found that: 1) subjects responded reliably lo tones presented during sleep; 2) behavioral control was accompanied by brief electro‐physiological indices of arousal on almost all trials, and occasionally led to fall awakenings; 3) sleep was markedly altered in the 1‐min condition; 4) a relatively small effect on sleep (reduced stage 4 sleep) was produced by the 4‐min condition, and 5) daytime sleepiness was increased by the 1‐min condition but not the 4‐min condition. It was concluded that the most parsimonious explanation of these results is (he Continuity of Sleep hypothesis.
Event‐Related Potentials to Breaks in Sequences of Alternating Pitches or Interstimulus Intervals
Authors: Nordby Helge , Roth Walton T. , Pfefferbaum Adolf 
Published: February 2007

ABSTRACTFourteen subjects were run in paradigms designed to explore event‐related brain potentials (ERPs) elicited by breaks in alternations in pitch or interstimulus interval. In the Pitch paradigm, tones of 500 Hz or 1000 Hz were presented in alternation at regular interstimulus intervals of 800 ms. In the Rhythm paradigm, a single tone, either 500 Hz or 1000 Hz, was presented at interstimulus intervals alternating between 400 ms and 800 ms. Breaks in the Pitch paradigm consisted of a single repetition of a pitch, and in the Rhythm paradigm of a single repetition of the 400‐ms interstimulus interval. Breaks occurred with a 10% probability in both cases. Subjects read while stimuli were being presented.A N210 wave of about 3.5 μV was elicited by breaks in pitch pattern but not by breaks in rhythm. That it was largest (most negative) frontally suggests that it was a type of mismatch negativity. Analysis of waveforms constructed by subtracting ERPs to standards from ERPs to breaks confirmed these results. Thus we conclude that the system triggering mismatch negativity can encode the temporal ordering of pitches.
Microcomputer Automated System for Measuring Systolic Time Intervals in Response to Exercise and a Psychophysiological Task
Authors: VanDercar David H. , Laperriere Arthur R. , Shyu Liang Yu , Ward Michael F. , McCabe Philip M. , Perry Arlette , Schneiderman Neil 
Published: February 2007

ABSTRACTA microcomputer automated system for measuring systolic time intervals is described. Electrocardiogram, phonocardiogram, and carotid pulse tracings were measured in 38 healthy male subjects during baseline conditions and during either exercise on a bicycle ergometer or a video‐game task. These measurements were recorded on both a traditional 3‐channel ECG recorder and the computerized system. Both methods of recording systolic time intervals were independently scored by two different experimenters. In this way, interrater reliability of hand‐scoring, intermethod reliability between hand‐scoring versus computer‐scoring, and interrater reliability of computer‐scoring could be assessed.The interrater reliabilities of hand‐scored systolic time intervals were generally above .90, ranging from .73 for left ventricular ejection time to .99 for R‐R intervals of the ECG, with a mean of .92. The intermethod reliability of the computer versus hand‐scored systolic time intervals also proved to be generally above .90, ranging from .76 for S1‐S2 components of the phonocardiogram to .99 for R‐R, with a mean of .94. The interrater reliabilities of the computer‐scored systolic time intervals were all above .90, ranging from .93 for S1‐S2 to .99 for R‐R, with a mean of .98.These data indicate that the computerized method of scoring systolic time intervals is at least as reliable as the more traditional scoring of paper tracing.
Scoring Criteria for Electrodermal Habituation: Further Research
Authors: Vossel Gerhard , Zimmer Heinz 
Published: February 2007

ABSTRACTIn the context of Levinson and Edelberg's critique of scoring criteria for electrodermal habituation, the present study examined the question of whether trials‐to‐habituation scores based on two no‐response trials are superior to scores based on three no‐response trials. Male students (N=120) performed two identical habituation experiments on two consecutive days and their skin conductance responses based on a short latency window of 1–3 s were analyzed. In each experiment subjects received 20 presentations of a 1000 Hz tone at 65dB. Results showed that three‐trials scores were higher overall and that the distributions of three‐ and two‐trials scores differed. On the other hand, the twoscores had comparable retest‐reliabilities, displayed similar correlations with regression indices and resting nonspecific activity, and reliably reflected the changes in habituation speed from the first to the second session. Furthermore, three‐ and two‐trials scores were found to be highly interrelated. It was concluded that the findings obtained for our particular sub‐population of male students do not favor one or the other of the two scoring methods for trials‐to‐habituation scores and that the establishment of standardized scoring criteria should be attempted.
Human Brainstem Auditory Evoked Potentials Fail to Provide Evidence of Efferent Modulation of Auditory Input During Attentional Tasks
Authors: Connolly John F. , Aubry Karen , McGillivary Nicole , Scott Donald W. 
Published: February 2007

ABSTRACTEfferent modulation of auditory input at the level of the brainstem during attention‐demanding tasks has been described in animal studies. Attempts to demonstrate these effects in humans have produced conflicting results, however. These studies are reviewed with particular reference to those animal experiments that have demonstrated peripheral effects. The human experiments have used a number of attentional conditions which have not been related either to each other or to the successful animal work. Two of the most important conditions in these studies–the use of an intermodal attention task and the manipulation of attentional states–have been examined rarely or not at all in the human research. Two experiments were conducted to investigate the possibility of attention‐related effects on the human brainstem auditory evoked potential. These experiments were designed to examine experimental conditions common to both successful and unsuccessful attempts to demonstrate attention‐driven efferent modulation at the periphery in humans. Also examined was the gradation of attention effects on efferent modulation demonstrated in animals but never studied in humans.No significant changes in either the latency or the amplitude of the brainstem auditory evoked potential were found in any of the attention‐demanding conditions. Results are discussed in terms of psychophysiological theories of attention. Also, the interpretation of the most recent animal work is questioned.
Effects of Smoking/Nicotine on Anxiety, Heart Rate, and Lateralization of EEG During a Stressful Movie
Authors: Gilbert David G. , Robinson John H. , Chamberlin Carl L. , Spielberger Charles D. 
Published: February 2007

ABSTRACTThe effects of smoking cigarettes with differing FTC nicotine deliveries on anxiety and EEG activity were evaluated in 40 smokers who were compared with 40 non‐smokers, matched for age and gender. Following smoking (sham‐smoking in the case of the non‐smokers), the participants viewed a stress‐inducing movie. Smoking higher‐nicotine delivery cigarettes during the movie, as compared to smoking low‐nicotine control cigarettes, was associated with reductions in anxiety and right hemisphere activation, increased heart rate, and enhancement of the ratio of left‐hemisphere parietal EEG activation to right‐hemisphere activation. These results are interpreted as indicating that the anxiolytic effects of nicotine may be mediated by the right hemisphere. The EEG activity and emotional responses of non‐smokers were more like those of smokers who smoked the lower‐nicotine cigarettes than those of smokers of the higher‐nicotine cigarettes.