bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Baroreceptor Reflex Function During Mental Stress and Relaxation
Authors: Steptoe Andrew , Sawada Yukihiro
Published: February 2007

This 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

The 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

The 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

There 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

The 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

Ambulatory 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

The 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

The 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

A 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

The 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

Some 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

Inborn 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

This 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

ECG 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.
A Comparison of Three Quantification Methods for Estimation of Respiratory Sinus Arrhythmia
Authors: Grossman P. , van Beek J. , Wientjes C.
Published: February 2007

The empirical literature has shown that respiratory sinus arrhythmia is a sensitive noninvasive index of parasympathetic cardiac control. Nevertheless there has been no general agreement among investigators as to the most preferable quantification technique for assessing respiratory sinus arrhythmia, although there has been much speculation that specific estimation techniques are more or less reflective of vagal processes and could be more or less contaminated by other influences upon heart period variability unrelated to respiration. This study compared three quantification procedures for estimating respiratory sinus arrhythmia (RSA): (1) a spectral analytic technique, (2) a complex detrending approach removing periodic and aperiodic cardiac variations unrelated to respiration, and (3) a time‐domain, peak‐valley procedure employing inspiratory and expiratory periods as windows for determining range of cardiac‐interval fluctuations associated with respiratory phase. Measures derived from these techniques were intra‐ and interindividually compared using three different samples of male subjects, including students, adult normotensives, and adult hypertensives. All interindividual correlations between measures yielded coefficients above .92 and the mean within‐subject correlation across 42 individuals was .96, thus indicating a marked degree of comparability between measures. Additionally, given that much evidence indicates lawful within‐individual relations between RSA amplitude and respiratory parameters, we employed respiratory period as an external criterion and compared intraindividual correlations between this variable and (2) and (3); results showed that (3) was significantly more highly associated with respiration than was (2), although the mean r's for the two measures did not diverge greatly (.91 vs. 84). Finally, inspection of the data and further regression analyses did not suggest that any of the RSA estimates were differentially contaminated by other components of cardiac variability. Our findings suggest that the three techniques are almost equivalent as indices of cardiac vagal tone and would appear to ease concerns about the inferiority of any of the procedures. Choice of a quantification procedure should therefore be tailored to the specific empirical needs of an investigation. The advantages and disadvantages of each method are discussed.
Mismatch Negativity Outside Strong Attentional Focus: A Commentary on Woldorff et al. (1991)
Authors: Näätänen Risto
Published: February 2007

Several previous papers have suggested that the mismatch negativity (MMN), an event‐related potential (ERP) component specific to stimulus change after repetition, is fully automatic, that is, not affected by attention. Woldorff, Hackley, and Hillyard (1991), however, report that the MMN elicited by an intensity decrement of a repeating stimulus is considerably attenuated when attention is strongly focused on other stimuli. The present commentary attributes most of this effect to attention effects on ERP components other than the MMN but also admits that some attentional reduction of the MMN component indeed occurred. This attenuation was interpreted by Woldorff et al. as indicating suppression of early sensory processing in unattended channels, but this is contraindicated by some very recent data from the present author's laboratory and elsewhere showing that the MMN to frequency change is not attenuated outside a strong attentional focus. Consequently, an alternative explanation is proposed for Woldorff et al.'s important finding.
The Truth Will Out: Interrogative Polygraphy (“Lie Detection”) With Event‐Related Brain Potentials
Authors: Farwell Lawrence A. , Donchin Emanuel
Published: February 2007

The feasibility of using Event Related Brain Potentials (ERPs) in Interrogative Polygraphy (“Lie Detection”) was tested by examining the effectiveness of the Guilty Knowledge Test designed by Farwell and Donchin (1986, 1988). The subject is assigned an arbitrary task requiring discrimination between experimenter‐designated targets and other, irrelevant stimuli. A group of diagnostic items (“probes”), which to the unwitting are indistinguishable from the irrelevant items, are embedded among the irrelevant. For subjects who possess “guilty knowledge” these probes are distinct from the irrelevants and are likely to elicit a P300, thus revealing their possessing the special knowledge that allows them to differentiate the probes from the irrelevants. We report two experiments in which this paradigm was tested. In Experiment 1, 20 subjects participated in one of two mock espionage scenarios and were tested for their knowledge of both scenarios. All stimuli consisted of short phrases presented for 300 ms each at an interstimulus interval of 1550 ms. A set of items were designated as “targets” and appeared on 17% of the trials. Probes related to the scenarios also appeared on 17% of the trials. The rest of the items were irrelevants. Subjects responded by pressing one switch following targets, and the other following irrelevants (and, of course, probes). ERPs were recorded from Fz, Cz, and Pz. As predicted, targets elicited large P300s in all subjects. Probes associated with a given scenario elicited a P300 in subjects who participated in that scenario. A bootstrapping method was used to assess the quality of the decision for each subject. The algorithm declared the decision indeterminate in 12.5% of the cases. In all other cases a decision was made. There were no false positives and no false negatives: whenever a determination was made it was accurate. The second experiment was virtually identical to the first, with identical results, except that this time 4 subjects were tested, each of which had a minor brush with the law. Subjects were tested to determine whether they possessed information on their own “crimes.” The results were as expected; the Guilty Knowledge Test determined correctly which subject possessed which information. The implications of these data both for the practice of Interrogative Polygraphy and the interpretation of the P300 are discussed.
Orienting, Habituation, and Resource Allocation: An Associative Analysis
Authors: Siddle David A.T.
Published: February 2007

This paper addresses the question of the most appropriate theoretical account of the phenomena of orienting and habituation. Several lines of evidence are reviewed. First, it is argued that the effects of stimulus omission require a comparator theory in which it is asserted that responses to iterated events result from a comparison between predicted and actual stimulus input. Second, the data from studies in which paired stimulus events are employed seem, at least at first sight, to be best explained in terms of a comparator theory in which a key role is ascribed to associative processes. Third, secondary task probe reaction time data indicate that events that elicit orienting also command processing resources, and that habituation involves changes in the manner in which events are processed. Finally, recent data on the effects of intermodality change indicate that electrodermal responses are larger on the change trial than on the first habituation training trial; these results seem problematical for noncomparator theories. However, other data on the context‐specificity of habituation and on the effects of stimulus miscuing cast doubt on the usefulness of an associative analysis as a general account of habituation phenomena. Nevertheless, the weight of evidence seems to indicate that an adequate theory of human habituation must include a comparison process and must acknowledge that orienting and habituation involve a re‐allocation of attentional resources.
Startle and Emotion: Lateral Acoustic Probes and the Bilateral Blink
Authors: Bradley Margaret M. , Cuthbert Brucse N. , LANG Peter J.
Published: February 2007

The affect‐startle effect describes the modulation of the reflexive eyeblink response to a probe startle stimulus as a function of foreground emotional valence. Larger blinks occur during viewing of unpleasant slide foregrounds, relative to positive foregrounds. This effect has been obtained repeatedly using binaural acoustic startle probes. The current study examines this phenomenon for monaural probes administered to the left and right ears in separate blocks. Startle probes were presented during and between exposures to pleasant, neutral, and unpleasant slides, with the ear of presentation counterbalanced across subjects. Left monaural probes produced blink magnitudes that increased linearly from pleasant to unpleasant slide foregrounds, and appeared to be independent of attention or interest. Right monaural probes did not vary with foreground valence. These findings suggest that the startle probe indexes emotional processing that is lateralized in the central nervous system.
Ongoing Pain as a Mental Workload Indexed by P300 Depression: Discrimination of Real and Feigned Pain Conditions
Authors: Rosenfeld J. Peter , Kim Meekyung
Published: February 2007

Two groups of subjects were formed. One, a real pain group, was subjected to aversive pressure on the fingernail surface during pain‐only and pain‐tracking conditions. The second group (feigned pain) was instructed to feign pain during corresponding runs in which fingernail pressure was applied at a just noticeable (not painful) level. Both groups also simultaneously performed an auditory oddball (.8/.2) task during their pain‐only and pain‐tracking conditions, as well as during an initial (baseline‐1) and final (baseline‐2) baseline condition in which only the oddball task was performed. Oddball‐evoked P300 amplitudes were significantly different for the groups during the pain‐tracking and baseline‐2 conditions, with the amplitudes smaller in the real pain groups in both conditions. The pain‐only and pain‐tracking conditions in both groups caused significant P300 reductions in comparison with baseline‐1 values. P300 latencies did not differ as a function of either groups or conditions. 100% of the real pain subjects and 67% of the feigned pain subjects could be correctly classified using P300 amplitude‐derived indices.
The Effects of Channel‐Selective Attention on the Mismatch Negativity Wave Elicited by Deviant Tones
Authors: Woldorff Marty G. , Hackley Steven A. , Hillyard Steven A.
Published: February 2007

The mismatch negativity (MMN) is an event‐related brain potential elicited by infrequent, physically deviant sounds in a sequence of repetitive auditory stimuli. Two dichotic listening experiments that were designed to optimize the selective focusing of attention provided a strong test of Näätänen's proposal that the MMN is unaffected by attention and reflects the operation of a strongly automatic mismatch detection system. In Experiment 1, tones were presented at intervals of 120‐320 ms, and the deviant tones (intensity decrements) in both the attended and unattended ears elicited negative waves consistent in waveshape, latency, and distribution with previously described MMNs. In contrast to previous reports, however, the MMN elicited by the unattended‐channel deviant was markedly reduced (peak amplitude of less than 1 μV) relative to the corresponding negative wave elicited by the attended‐channel deviants (3–4 μV), as well as relative to previously reported MMNs (3–6 μV) elicited by comparable deviations in stimulus intensity. In Experiment 2, which employed interstimulus intervals of 65–205 ms, the unattended‐channel MMN elicited by the deviant fainter tones was barely discernible, whereas the corresponding attended‐channel negativity was again about 3‐4 μV.

These findings call into question the assertion that the auditory mismatch detection process and the associated MMN wave are wholly independent of attentional influence. Rather, these data provide evidence that the processing of stimuli in unattended channels can be attenuated or gated at an early sensory level under conditions of highly focused auditory selective attention.
Heart Rate Variability During Attention Phases in Young Infants
Authors: Richards John E. , Casey Betty Jo
Published: February 2007

Heart rate variability during visual attention was studied in infants who were tested cross‐sectionally at 14, 20, or 26 weeks of age. They were presented with a recording of a Sesame Street program on a TV screen. After heart rate had decelerated below the prestimulus level and then returned to prestimulus level, a computer‐generated pattern replaced the Sesame Street display. Heart rate variability changed throughout attention. The change consisted of a decrease in variability during attention and a return to prestimulus levels approximately five seconds following attention termination. The heart rate and variability responses are consistent with a model of parasympathetic vagal influence on the heart in which vagal firing is increased during sustained attention and is inhibited during attention termination.
What do Arithmetic Stress Tests Measure? Protocol Variations and Cardiovascular Responses
Authors: Linden Wolfgang
Published: February 2007

Three studies tested the effects of the following design/protocol variations in mental arithmetic: 1) Order of task, 2) vocal versus written delivery of responses, 3) effects of different types of superimposed noise distractors, and 4) varying types of mental arithmetic challenges. All studies used the same basic protocol with 20‐min adaptation, 5‐min task, and 3‐min recovery periods; dependent cardiovascular variables were systolic and diastolic blood pressure and heart rate; in Study 2 respiration rate and respiratory amplitude were also assessed.

Findings showed that vocal delivery enhanced subjective distress, lowered performance, and enhanced diastolic blood pressure responses. Noise distraction augmented distress but did not affect task performance. Variable noise distraction augmented systolic blood pressure and heart rate responses but only when math equations were presented on a video screen. Autonomic response adaptation was apparent from first to second tasks but not thereafter. The built‐in replications strengthened these findings.
Removal of the Ocular Artifact from the EEG: A Comparison of Time and Frequency Domain Methods with Simulated and Real Data
Authors: Kenemans J. Leon , Molenaar Peter C.M. , Verbaten Marinus N. , Slangen Jef L.
Published: February 2007

Frequency‐dependent transfer from EOG to EEG may be insufficiently accounted for by simple time domain regression methods (Gasser, Sroka, & Möcks, 1986; Woestenburg, Verbaten, & Slangen, 1983). In contrast, a multiple‐lag time domain regression analysis, using lagged regression of EEG on EOG, must theoretically account for both frequency dependence and independence.

Two data sets were constructed, in which the transfer from EOG to EEG was either frequency‐independent (constant gain) or frequency‐dependent. Subsequently, three different correction methods were applied: 1) a simple regression analysis in the time domain; 2) a multiple‐lag regression analysis in the time domain; and 3) a regression analysis in the frequency domain.

The major results were that, for data set 1, the three methods constructed the original EEG equally well. With data set 2, reconstruction of the original EEG was achieved reasonably well with the frequency domain method and the time domain multiple‐lag method, but not with simple time domain regression. These three correction procedures were also applied to real data, consisting of concomitantly recorded EEG and high‐variance EOG series. No appreciable differences in outcome of the three methods were observed, and estimated transfer parameters suggested that these data were marked by weak frequency dependence only, which can be accounted for by simple time domain regression (and also by the other two methods).
Dimensional Analysis of No‐Task Human EEG Using the Grassberger‐Procaccia Method
Authors: Pritchard Walter S. , Duke Dennis W.
Published: February 2007

A method developed by Grassberger and Procaccia allows estimation of the dimensional complexity of the state‐space attractor of a time series. Saturation of dimensional‐complexity estimates with increasing values of embedding dimension is considered a strong indication that the time series is governed by deterministic chaos. The present investigation employed the Grassberger‐Procaccia method to estimate EEG dimensional complexity in a multi‐subject, factorial experiment. Twelve subjects were tested under two no‐task conditions (eyes closed and open), with the block of two conditions being repeated four times. EEG was recorded from the nineteen 10‐20 loci. Dimensional complexity declined across Blocks 1‐3 and then leveled off, and was higher in the eyes‐open than in the eyes‐closed condition. Condition also interacted with locus in that the increase in dimensional complexity associated with opening the eyes was greater over occipital loci. Comparison with the results of Fourier analysis indicated that a similar but not identical pattern of effects was obtained for alpha (8‐12 Hz) power. Further, across the entire data set, if alpha power exceeded a value of about 70 μV2, demensional complexity was uniformly low, a finding in concert with previous results indicating that the eyes‐closed, occipital alpha rhythm possibly represents deterministic chaos of relatively low dimension.
Pregnancy Alters Blood Pressure Responses to Psychological and Physical Challenge
Authors: Matthews Karen A. , Rodin Judith
Published: February 2007

The purpose of the study was to evaluate the effect of the substantial changes in female reproductive hormones that occur during normal pregnancy on cardiovascular responses to psychological and physical challenges. Twenty‐one healthy normotensive women performed serial subtraction, mirror image tracing, and isometric handgrip exercise tasks prior to pregnancy and again during the second trimester of pregnancy. A control group of 34 healthy women who did not intend to become pregnant and were nonpregnant were also tested in the same protocol twice, 6–10 months apart. Results showed that the pregnant women exhibited a reduced diastolic blood pressure response to all three tasks, relative to their pre‐pregnancy levels, whereas nonpregnant controls did not change in their diastolic blood pressure response across time. These results are consistent with the hypothesis that elevations in female reproductive hormones diminish blood pressure responses during challenge because of dampened sympathetic nervous system activity.
Increased Salivary Cortisol in Severe Dental Anxiety
Authors: Benjamins Carmen , Asscheman Henk , Schuurs Albert H.B.
Published: February 2007

The aim of the present study was to investigate the feasibility of saliva collection from highly anxious dental patients and to evaluate whether salivary cortisol concentrations could discriminate between 13 highly anxious dental patients and 13 non‐anxious subjects. Whole mixed saliva was sampled by suction after stimulation with citric acid crystals. Salivary free cortisol levels were measured in duplicate by radioimmunoassay. Collection of saliva took 2–5 min and was not experienced as unpleasant. Salivary free cortisol concentrations were significantly elevated if the patients manifested anxiety according to the scores on the Dental Anxiety Scale. The measurement of salivary cortisol may be a convenient method for the assessment of dental anxiety.
Myocardial and Peripheral Vascular Responses to Behavioral Challenges and Their Stability in Black and White Americans
Authors: Saab Patrice G. , Llabre Maria M. , Hurwitz Barry E. , Frame Charles A. , Reineke Lori J. , Fins Ana I. , McCalla Judith , Cieply Larry K. , Schneiderman Neil
Published: February 2007

The purpose of this study was to assess the short term stability of myocardial and peripheral vascular responses to behavioral challenges, and to compare the response patterns of Black and White men. Blood presure and heart rate, as well as stroke volume, cardiac output, total peripheral resistance, and systolic time interval measures derived from the impedance cardiogram were obtanined in 12 Black and 12 White men. These measures were taken prior to and during an evaluative speech stressor, a mirror star tracing task, and a forehead cold pressor test presented during two laboratory sessions scheduled two weeks apart. In general, total peripheral resistance and impedance‐derived baseline measures showed acceptable reproducibility (G>.85). With a few exceptions, adequate reliability was also demonstrated for change (delta) scores. All tasks raised blood pressure responses above resting levels. Blacks demonstrated significantly greater increases in total peripheral resistance responses across tasks. Whites but not Blacks also revealed increases above baseline in cardiac output and contractility as estimated by the Healther Index. These findings are consistent with the view that Blacks show greater vascular responsiveness than Whites across a variety of tasks, but reveal less myocardial responsiveness.
Event Related Potentials and EEG Components in a Semantic Memory Search Task
Authors: Mecklinger Axel , Kramer Arthur F. , Strayer David L.
Published: February 2007

This study examined the effects of memory search and related processes on both time and frequency domain components of electroencephalographic activity. More specifically, we were interested in the relationship between EEG and event‐related potential (ERP) components as a function of memory load and response type. Subjects performed a semantic memory search task in which they matched word probes to category labels. Consisten with previous studies, reaction time increased and accuracy decreased with increasing memory loads. A negative component of the ERP (N400) was found to reflect semantic mismatch: N400s were larger for the nontargets than for the targets. Two ERP components were found to be reciprocally related to memory load. P300 decreased and Negative Slow Wave increased in amplitude with increases in the size of the memory set. These two ERP components were reflected by different components in a Principal Components Analysis. The power in the theta band (5–7 Hz) also increased as a function of memory load and appears to be functionally and topographically related to the Negative Slow Wave in the ERP. It is argued that both measures are jointly determined and reflect the difficulty of the conceptual operations during memory search.
Frequency‐Specific Amplification of Heart Rate Rhythms Using Oscillatory Tilt
Authors: Byrne Evan A. , Porges Stephen W.
Published: February 2007

Heart rate rhythms have been demonstrated to parallel specific psychological processes. Efficient experimental control of the amplitude of these rhythms would allow evaluation of bidirectional psychophysiological hypotheses. This experiment was performed to examine the specificity of the heart rate rhythm response to oscillatory head‐up tilt. Seventy‐one adults (36 male, 35 female) aged 18–30 were positioned on a tilt‐table and oscillated at 0.08 Hz with a maximum tilt angle of +210 for a 10‐min period. Heart period, heart period variability at 0.08 Hz (i.e., Traube‐Hering‐Mayer (THM) variance), and respiratory sinus arrhythmia (quantified using vagal tone, V̂) were measured. For a subset of 21 subjects, continuous measures were derived to examine the response to onset of oscillatory tilt. Respiratory activity was also measured in these subjects. There was a significant increase in the amplitude of the THM variance during tilt stimulation. Tilt did not significantly change heart period, V̂, or respiration frequency. Following cessation of tilt, THM variance returned to baseline levels, heart period lengthened for males, and V̂ increased for both sexes. Subjects with higher amplitude baseline V̂ were characterized by more rapid THM variance response to tilt. Results suggest that parasympathetic tone moderates the THM variance increase elicited by low‐frequency oscillatory tilt.
Recent Developments in the Study of Cardiovascular Reactivity: Contributions from Psychometric Theory and Social Psychology
Authors: Kamarck Thomas W.
Published: February 2007

Two related ongoing research programs are described. The first examines optimal measurement strategies for assessing individual differences in cardiovascular reactivity, and the second investigates the effects of the social environment as a moderator of cardiovascular responding during psychological challenge. Models and evidence from related behavioral sciences (Psychometric Theory and Social Psychology, respectively) have provided useful guidance for this work. Relevant background and current data examining the measurement and determinants of cardiovascular reactivity are reviewed, with a focus on these multidisciplinary contributions. The implications of the work for the construct of reactivity and its possible role as a marker of disease risk are discussed.
The Temporal Locations of Heartbeat Sensations
Authors: Ring Christopher , Brener Jasper
Published: February 2007

This experiment examined individual differences in the temporal location of heartbeat sensations and the reliability of their detection. Following practice on a familiarization task in judging lighttone simultaneity, 50 subjects were studied for two sessions on a heartbeat detection task, which required judging the simultaneity of heartbeat sensations and tones presented at six intervals following the onset of ventricular contraction. Subjects inspected the heartbeat‐tone intervals as frequently and for as long as desired before choosing the one in which heartbeat sensations and tones were most simultaneous. The temporal locations of heartbeat sensations in subjects classified as “good heartbeat perceivers”(n = 16) ranged from 131 and 363 ms following ventricular contraction (mean = 228 ms). Correlations between the familiarization and heartbeat detection tasks in the accuracy of simultaneity judgments and in the frequency and duration of interval inspections suggest that general perceptual abilities and strategies may underlie success in detecting heartbeat sensations.