bluuebunny/crossref_metadata_2025 huggingface dataset:
Methodological Guidelines for Impedance Cardiography
Authors: Sherwood(Chair) Andrew , Allen Michael T. , Fahrenberg Jochen , Kelsey Robert M. , Lovallo William R. , van Doornen Lorenz J.P.
Published: February 2007

Impedance cardiography was introduced over 20 years ago as a noninvasive and unobtrusive technique for measuring systolic time intervals and cardiac output. Although our understanding of the physiological events reflected in the impedance cardiogram has become more refined, the technique's theoretical basis remains somewhat controversial and acceptance of its validity has relied heavily upon empirical validation. Largely as a consequence of this status, there have been inadequate grounds on which to develop sound methodological standardization. Currently, the methodological approaches that have been most frequently adopted may be viewed as representing the standard. The various aspects of impedance methodology are discussed, and alternative approaches described, with the objective of providing an informed basis for choosing among these methodological alternatives. It is recommended that studies utilizing impedance cardiography should be reported with clear and detailed methodological description. This should help clarify the extent to which methodological differences may underlie any discrepant research observations, as well as facilitate the emergence of improved methodological standards.
Comparing Principal Components Analyses of Evoked Potentials Recorded from Heterogeneous Groups of Subjects
Authors: Roemer Richard A. , Josiassen Richard C. , Shagass Charles
Published: February 2007

Principal components analysis of evoked potentials differing between groups presents an interpretive problem, particularly in psychiatric research. Two sets of principal components and associated factor scores may appear to differ. The issue is to determine the extent to which visually differing principal components and resultant factor scores span the same factor space. Sets of evoked potentials from controls and from schizophrenics were each subjected to principal components analysis, from which factor score coefficients were computed for all subjects. This allowed determination of the extent to which (1) the two sets of basis waves were similar and (2) the factor scores resulting from the set of basis waves derived from principal components analysis of the control subjects’ evoked potential data adequately represented those of the schizophrenics and vice‐versa. Canonical correlation analyses indicated substantial similarities between the principal component structures (sets of basis waves). Multiple correlational analyses confirmed that the basis waves from either group spanned the other group's factor space. Factor scores from either set of basis waves were highly correlated. These results suggest that principal component structures derived from evoked potentials of a control group may be used in computing evoked potential factor scores of psychiatrically diverse populations even though the average evoked potentials of the groups may differ in several ways.
Paced Respiratory Sinus Arrhythmia as an Index of Cardiac Parasympathetic Tone During Varying Behavioral Tasks
Authors: Grossman P. , Stemmler G. , Meinhardt E.
Published: February 2007

This study addresses a number of unresolved issues regarding the employment of respiratory sinus arrhythmia as an index of tonic parasympathetic cardiac control in psychophysiological investigations. These questions include the following: (1) Does respiratory sinus arrhythmia reflect cardiac vagal tone under conditions in which alterations in parasympathetic control are expected to be mild to moderate? (2) Are variations in human respiratory sinus arrhythmia that occur in response to varying behavioral demands independent of beta‐adrenergic effects on the heart? (3) To what extent do typical experimental tasks apparently affect tonic cardiac vagal control?

Twelve healthy male subjects were administered a joint alpha‐ and β‐adrenoreceptor pharmacological blocker on one day and a placebo on another (balanced across subjects). On both days, respiratory sinus arrhythmia and heart period were monitored during a number of different experimental tasks while subjects continuously paced their respiration.

Results indicated that respiratory sinus arrhythmia, under controlled respiratory conditions, is uninfluenced by variations in sympathetic activity, and provides a reasonably sensitive index of cardiac vagal tone, even when alterations in parasympathetic tone are not large. Furthermore, our findings suggest that cardiac vagal tone is responsive to varying behavioral demands and may interact in different ways with β‐adrenergic mechanisms.
Interpersonal Influence as Active Coping: Effects of Task Difficulty on Cardiovascular Reactivity
Authors: Smith Timothy W. , Baldwin Michael , Christensen Alan J.
Published: February 2007

This study examined the effects of attempting social influence on cardiovascular reactivity. Subjects were randomly assigned to a noncontingent reward condition or one of three conditions in which receipt of a monetary reward was contingent on their ability to influence another individual through a persuasive communication. In the contingent conditions, the task was presented as either easy, difficult, or very difficult. Measures of systolic blood pressure, diastolic blood pressure, and heart rate were recorded while subjects prepared and delivered the persuasive communication (contingent conditions) or reviewed and read aloud the same statement without an incentive to influence. The contingent conditions produced significantly higher levels of systolic and diastolic blood pressure and heart rate reactivity during preparation and speaking. Further, reactivity was higher in the difficult condition than in the easy and very difficult conditions. The findings are discussed in terms of an interpersonal equivalent of traditional active coping tasks.
Hemispheric Asymmetry in Conditioning to Facial Emotional Expressions
Authors: Johnsen Bjørn Helge , Hugdahl Kenneth
Published: February 2007

In the present experiment, we report a right hemisphere advantage for autonomic conditioning to facial emotional expressions. Specifically, angry, but not happy, facial expressions showed significantly more resistance to extinction when presented initially to the right as compared to the left hemisphere. Slides of happy and angry faces were used as conditioned stimuli (CS+ and CS−) with shock as the unconditioned stimulus (UCS). Half of the subjects (n=15) had the angry face as CS+ (and the happy face as CS−), the other half had the happy face as CS+ (and the angry face as CS−). During acquisition, the CSs were presented foveally. During extinction, using the Visual Half‐Field (VHF) technique, half of the CS+ and CS− trials were randomly presented in the right visual half‐field (initially to the left hemisphere), and half of the trials were presented in the left half‐field (initially to the right hemisphere). Stimuli were presented for 210 ms during acquisition, and for 30 ms during extinction. Bilateral skin conductance responses (SCRs) were recorded. The results showed effects of acquisition only for the angry CS+ group. During extinction, there was a significant Conditioning X Half‐field interaction which was due to greater SCRs to the CS+ angry face when it was presented in the left half‐field. It is concluded that the present results reveal hemisphere asymmetry effects in facial emotional conditioning.
P300 and Introverted/Extraverted Personality Types
Authors: Ditraglia Gina M. , Polich John
Published: February 2007

The P300 component of the event‐related potential elicited with a two‐tone auditory discrimination task and two‐trial block replication procedure was obtained from 16 introverted and 16 extraverted undergraduate students. P300 demonstrated no overall significant effects for either the personality variable or the block variable. However, P300 amplitude to the target stimuli declined significantly between Block 1 and Block 2 for the extraverted subjects, but did not change across trial blocks for the introverted group. Female subjects tended to have larger P3 amplitudes than male subjects, but this factor did not interact with either the personality variable or the trial block variable. The results suggest that P3 amplitude habituates more rapidly for extraverts than for introverts.
A Model of Cardiovascular Activation Components for Studies Using Autonomic Receptor Antagonists
Authors: Stemmler Gerhard , Grossman Paul , Schmid Holger , Foerster Friedrich
Published: February 2007

Alpha‐adrenergic, beta‐adrenergic, and cholinergic responses are often considered important activation components when conceptual and empirical analyses are made of single physiological variables and of patterns of cardiovascular reactivity; these autonomic distinctions are also of particular significance in autonomic blockade studies. A Model of Cardiovascular Activation Components is introduced that relates these components to both the measured cardiovascular variables and the protocol of autonomic blockade studies. It is pointed out that a restricted form of the complete model is often implicitly used in cardiovascular psychophysiology. The differential consequences of an erroneous employment of the restricted model are discussed for single and dual blockade protocols. Critical evaluations of autonomic blockade as a tool in cardiovascular psychophysiology are examined and are proposed to be often the consequence of the restricted model assumptions. Lastly, the utility of the Activation Components Model for a componential description of tasks and for componential intertask relationships is illustrated with data from the literature.
The Waltzing Oddball
Authors: Verleger Rolf , Berg Patrick
Published: February 2007

We investigated whether task relevance and probability interact to influence P3 amplitude. High and low tones were presented in random order with equal probability. In the control condition (standard oddball), every high tone had to be counted. In the waltz condition, high tones had to be counted only if they were preceded by two other high tones. It was predicted that the P3s evoked by targets in the waltz condition would be larger than the P3s evoked by the same sequence of targets in the oddball condition. That is, the frequency of occurrence of the targets should have an effect on P3, in addition to effects of the frequency of stimulus occurrence and stimulus task relevance (target/nontarget). This prediction was upheld. However, the largest P3s were evoked by nontargets following two high tones in the waltz condition. These P3s had a more anterior topographic maximum than usual. We contend that these anterior P3s reflect the interruption of an ongoing task and cannot be easily fit into the framework of the two concepts of task relevance and probability.
Heart Rate Reactivity, Behavior Pattern, and Parental Hypertension as Predictors of Cardiovascular Activity During Cognitive Challenge
Authors: Sausen Kenneth P. , Lovallo William R. , Wilson Michael F.
Published: February 2007

Hemodynamic responses were studied during work on serial subtraction and digits backwards tasks in 99 healthy male undergraduates jointly classified as high or low heart rate reactors, Type A or Type B behavior pattern, and as having positive or negative parental history of hypertension. Heart rate, systolic blood pressure, and diastolic blood pressure were recorded, and rate pressure product was calculated at rest and during the tasks. High heart rate reactors to a cold pressor task responded with relatively higher heart rate and rate pressure product during both cognitive tasks than low heart rate reactors. Type A subjects defined by Jenkins Activity Survey did not differ from Type Bs on any of these physiological variables, although behavioral evidence demonstrated greater effort and superior performance by the Type As. Subjects with a positive parental history of hypertension manifested greater systolic and diastolic pressures and rate pressure product responses to the cognitive challenge than those lacking such parental history. These results indicate that the individual difference variables of heart rate reactivity and parental history of hypertension predicted different hemodynamic response patterns to behavioral challenge.
Neuroendocrine and Cardiovascular Stress Reactivity in Middle‐Aged Normotensive Adults with Parental History of Cardiovascular Disease
Authors: Fredrikson Mats , Tuomisto Martti , Bergman‐Losman Bodil
Published: February 2007

Neuroendocrine and cardiovascular stress reactivity was studied in healthy middle‐aged individuals whose parental history included essential hypertension and/or myocardial infarction and a control group without parental history of cardiovascular disease. All subjects completed a rest session (1 hour) and a stress session (1 hour). The stress session included behavioral (mirror image tracing, mental arithmetic, and the Stroop color word conflict test) and physical stressors (the cold pressor test and isometric exercise). Systolic and diastolic blood pressures and heart rate were recorded at baseline before and during all stressors. Specimens for determination of urinary catecholamines and cortisol were sampled after the rest and stress sessions respectively. Generally, a parental history of hypertension but not of myocardial infarction influenced neuroendocrine and cardiovascular stress reactivity. A family history of hypertension was associated with exaggerated epinephrine, norepinephrine, and cortisol excretion during stress and with enhanced heart‐rate reactivity to behavioral (mental arithmetic and mirror image tracing) but not to physical stressors (isometric exercise or the cold pressor test). We conclude that individuals with a family history of hypertension tend to display exaggerated cardiovascular and neuroendocrine reactivity to stress.
Blood Pressure Reactivity and Perception of Pain During the Forehead Cold Pressor Test
Authors: Peckerman Arnold , Saab Patrice G. , McCabe Philip M. , Skyler Jay S. , Winters Ray W. , Llabre Maria M. , Schneiderman Neil
Published: February 2007

The relationship between blood pressure reactivity and the perception of pain was examined during a series of three forehead cold pressor tests given every other day to a group of 18 male college students. Subjects classified as high reactors on the basis of peak increases in mean blood pressure during cold pressor tests perceived the cold pressor stimulus as more painful than subjects classified as low reactors. The propensity to rate the cold pressor stimulus as painful was positively correlated with the individual level of blood pressure reactivity (baseline‐free partial r=.62). Intra‐individual correlations between pain and blood pressure responses were unrelated to subjects' reactivity status. Across the 3‐min test, correlations between pain and blood pressure reactivity (with the effects of baseline blood pressure levels partialled out) were significant only during periods when levels of responses were relatively high. The heart rate responses were unrelated to pain ratings. Generalizability theory was applied to the analysis of temporal stability of cold pressor reactions. Both blood pressure and pain responses were highly reproducible across three sessions, appearing to express stable individual differences. The efficacy of 800 mg oral ibuprofen in controlling the cold pressor pain was also tested. Analgesic activity of the drug during the cold pressor test could not be demonstrated.
EEG Alpha Methodologies and Hypnotizability: A Critical Review
Authors: Perlini Arthur H. , Spanos Nicholas P.
Published: February 2007

This paper reviews empirical studies that assessed the relationship between EEG alpha indices and measures of hypnotic responding. Although there are confirmatory reports of such a relationship, these findings have not been corroborated in repeated attempts at replication. The research is characterized by poor design and statistical procedures that fail to control for various extraneous factors. Although a few positive findings have been tentatively identified, they await replication. Taken together, the available evidence suggests that hypnotizability is not systematically related to alpha.
Neuroanatomical Correlates of Skin Conductance Orienting in Normal Humans: A Magnetic Resonance Imaging Study
Authors: Raine Adrian , Reynolds Gavin P. , Sheard Charlotte
Published: February 2007

Although little is known about the neuroanatomical basis of skin conductance orienting in intact normal humans, the limited literature on animals and humans with neurological and clinical disorders implicate prefrontal, temporal/amygdala, and pons brain areas in mediating skin conductance orienting. This study relates area of these structures using magnetic resonance imaging techniques to skin conductance orienting responses in 17 normal humans in order to test hypotheses that larger area of these excitatory structures will be associated with more orienting responses. Left and right hand skin conductance orienting was significantly associated with left and right prefrontal area (r=.44‐.60), area of the pons (r=.43‐.54), and left but not right temporal/amygdala area (r=.47‐.53). No relationships were observed with areas thought to be unrelated to skin conductance activity (cerebellum, nonfrontal cortical area), medial prefrontal cortex, or the third ventricle. This appears to be the first study relating brain structure to skin conductance orienting in intact normal humans. Although preliminary at the present time, these results implicate prefrontal, pons, and temporal/amygdala areas in the mediation of skin conductance orienting in normal humans.
Phenotypic Correlations between Oculomotor Functioning and Schizophrenia‐Related Characteristics in Relatives of Schizophrenic Probands
Authors: Clementz Brett A. , Sweeney John A. , Hirt Michael , Haas Gretchen
Published: February 2007

Abnormalities of visual pursuit tracking are frequent in the first‐degree relatives of probands with schizophrenia. The relationship between oculomotor abnormalities and schizophrenia‐related characteristics in those family members, however, has received little attention. Fifty‐three first‐degree relatives of 24 probands with schizophrenia were evaluated for the presence of schizophrenia‐related characteristics using both interview (Schedule for Schizotypal Personalities) and questionnaire (Chapman scales). The family members also had their eye movements recorded during pursuit tracking tasks and scored for gain in both the frequency and time domains, and saccadic intrusions. Social‐interpersonal schizophrenia‐related features were significantly related to both time‐ and frequency‐domain gain calculations. It appears that abnormalities in the smooth‐pursuit oculomotor system may be associated with symptoms conjectured to be most closely related to a genetic diathesis for schizophrenia. These findings provide further evidence that oculomotor abnormalities may be related to risk for this disorder.
Modulatory Influence of Continuous Tone, Tone Offset, and Tone Onset on the Human Acoustic Startle Response
Authors: Lane Shelly J. , Ornitz Edward M. , Guthrie Donald
Published: February 2007

Startle modulation in young adult men, by continuous background tone and its offset, a 2‐s sustained tone and its offset, and the onset of a 25‐ms tone pip were compared. Tone (75dB 1000 Hz) offset and onset occurred either 2000 ms or 100‐120 ms before the startle stimuli (104dB (SPL), 50‐ms white noise bursts). Blink amplitude and latency were unaffected by continuous background tone. Blink amplitude was reliably inhibited by 100‐ms offset of both the continuous background tone and the 2‐s sustained tone or 120‐ms onset of the tone pip, whereas effects on latency were more variable. Facilitation of blink amplitude and latency was significant but weak and only following the 2‐s sustained tone, and only with respect to one of two experimental contexts. These findings support those of others and suggest that startle inhibition results from activation of neurons responding to transient environmental changes. The degree of inhibition appears to be related to stimulus value. Startle amplitude facilitation following long sustained prestimulation intervals is dependent on experimental context. Overall latency and amplitude modulation tend to be concordant, leading to the conclusion that the mechanism(s) underlying both are context dependent and linked in the adult human.
Behavioral, Event‐Related Potential, and EEG/FFT Changes at Sleep Onset
Authors: Ogilvie Robert D. , Simons Iain A. , Kuderian Roxanne H. , MacDonald Thomas , Rustenburg John
Published: February 2007

Behavioral, event‐related potential (ERP), and EEG measures were obtained to describe more fully the relationship between brain activity and arousal level during the process of falling asleep. In addition to standard polysomnographic measures, tones were presented at random intervals throughout two nights to each of nine subjects. Subjects were instructed to respond to the tones whenever they heard them. Initial sleep onset was disrupted five times following zero through four successive response failures. Sampling of EEG was initiated 5 s prior to tone onset (EEG analyses) and continued for 5 s following tone onset (ERP data). With EEG ordered as a function of response rate, significant increases in power were found across all standard frequency bands for the pretone data at sleep onset. Significant changes in amplitude were related to decreasing responsivity for all late ERP components except P2. Inasmuch as virtually all EEG frequencies and ERP components were strongly influenced by momentary changes in arousal, arousal must be considered a (possibly the) primary determinant of the characteristics of the overall electrical output of the brain. Response cessation coupled with sharp increases in EEG synchronization mark the point of sleep onset.
The Relationship Between Cardiovascular and Catecholamine Reactions to Laboratory and Real‐Life Stress
Authors: van Doornen Lorenz J.P. , van Blokland Rian W.
Published: February 2007

Studies on the predictive value of stress testing in the laboratory for the reaction to real‐life stress have shown equivocal results. The variety of laboratory tasks differ for unknown reasons in their predictive power, and the results vary unsystematically among the physiological parameters measured. Most studies have focused on the prediction of ambulatory levels of blood pressure. Many other influences, besides stress, however, influence ambulatory levels. Therefore, a better operationalization of real‐life stress is to measure a person in a resting position during a period of well defined real‐life stress. The present study investigates whether the difference in ability of laboratory stress tasks to predict real‐life stress values is due to the different type of physiological response they induce. Hence, in the present study a more detailed measurement of the stress response was performed. A second question was whether stress testing would add to the prediction of the real‐life stress reactions above the prediction based on resting levels. This question was answered for both cardiovascular and catecholamine reactions to laboratory tasks. Two active coping tasks, one inducing a mainly cardiac‐sympathetic reaction and the other a relatively more vascular response, and a cold pressor test were administered to 33 healthy young males. Real‐life stress consisted of the anticipation of the public defence of the PhD thesis. Tasks indeed differed in predictive power, but this was not a function of the type of response they induced. The heart rate responses to a reaction time task and the heart rate and diastolic blood pressure reaction to the cold pressor test added significantly to the prediction of real‐life blood pressure levels and responses above the prediction on the basis of pretask baselines. The data suggest that the predictive value of the heart rate and blood pressure response to the cold pressor for the real‐life blood pressure response is due to noradrenergic reactivity as the common mechanism. Because mental tasks were not superior to the cold pressor in predicting the response to real‐life stress, it is concluded that it does not matter what kind of laboratory stressor is used for this purpose, as long as it adequately triggers a common physiological mechanism. The urine‐catecholamine reaction to the series of tasks was unrelated to the rise in catecholamines due to the real‐life stressor.
Electrodermal Lability: Individual Differences Affecting Perceptual Speed and Vigilance Performance in 9 to 16 Year‐Old Children
Authors: Sakai Laura M. , Baker Laura A. , Dawson Michael E.
Published: February 2007

Studies on adults have suggested that a deterioration in performance (within session vigilance decrement) on a continuous performance task may be related to individual differences in baseline levels of electrodermal activity (electrodermal lability). This study investigated this relationship in 153 children, aged 9–16 years. A significant vigilance decrement was observed, as indicated by average decreases in perceptual sensitivity (d') over an 11.5‐min time period. Although electrodermal labiles were overall more perceptually sensitive than electrodermal stabiles, results did not support the premise that the performance of stabiles decreases over time more than that of labiles. Performance on other cognitive tasks, involving tests of perceptual speed ability, did not appear to be highly related to vigilance performance. However labiles were not only better able to sustain their attention, but also performed better and faster on these cognitive tasks.
Is it Important That the Mind is in a Body? Inhibition and the Heart
Authors: Jennings J. Richard
Published: February 2007

The hypothesis is advanced that certain inhibitory processes necessarily involve autonomic adjustments. Such adjustments would represent a constraint on information processing imposed by the location of the mind in a body. Evidence is reviewed showing that motoric inhibition is related to a transient delay in heartbeat generation. The delay is shown to further depend upon when inhibition occurs in the cardiac cycle. It is argued that this form of interaction between central and autonomic nervous system processing may be common. Central nervous system processes that may control inhibition and integrate information processing with motoric and autonomic processes are discussed.
The Chronometry of Attention‐Modulated Processing and Automatic Mismatch Detection
Authors: Novak Gerald , Ritter Walter , Vaughan Herbert G.
Published: February 2007

Event‐related potentials were recorded from normal subjects in an auditory selective attention task. Targets were rare longer (170‐ms) tones of a designated pitch, embedded in a sequence of 100‐ms standard tones. The effects of attention‐modulated processing were evident in the event‐related potentials elicited by the standards. Those to relevant standards were similar for easy (1000 Hz vs. 2000 Hz) and hard (1000 Hz vs. 1030 Hz) pitch separations, and were more negative frontocentrally than those to irrelevant standards. Difference waveforms (attended minus unattended standards) revealed Nd, a negative deflection that was earlier in latency for the easy task (onset, 120 ms; peak, 250 ms) than for the hard task (onset, 250 ms; peak, 350 ms). The speed of detection of the deviant longer tones was insensitive to the attention‐modulated processes indexed by Nd. Median reaction time did not differ between tasks, although there were more misses and false alarms in the hard task (and nearly all of the latter were to the irrelevant longer tones). Neither direction of attention nor task difficulty affected the latency of mismatch negativity, N2, or P3 (as identified in difference waveforms: attended or unattended longer tones). minus their respective standards). The data suggest that performance was guided by two independent but converging processes, automatic mismatch detection of the longer tone and attention‐modulated processing of pitch, followed by selection of response.
Mismatch Negativity in Event‐Related Potentials to Auditory Stimuli as a Function of Varying Interstimulus Interval
Authors: Bottcher‐Gandor C. , Ullsperger P.
Published: February 2007

The mismatch negativity, isolated as a component of the event‐related brain potential elicited by deviant auditory stimuli, was suggested by Näätänen (1984) as an indirect measure of the inferred neuronal representation of standard stimuli. The purpose of the present study was to determine the duration of the neuronal representation by varying the interstimulus intervals of 1, 6, and 10 seconds within experimental blocks. Mismatch negativities were found to be elicited by deviant stimuli (1500‐Hz tones, sequential probability 10%) following standard stimuli (1000‐Hz tones) with interstimulus intervals of 1, 6, and 10 s as well. The results suggest a duration of neuronal representation of at least 10 s. The within‐block variation of interstimulus interval, the rather low temporal probability of deviants, and their large frequency deviance might explain the present results contradicting earlier findings that suggested a shorter duration of that neuronal representation.
Ambulatory Monitoring of Respiration: Inhibitory Breathing in the Natural Environment
Authors: Anderson David E. , Coyle Kristin , Haythornthwaite Jennifer A.
Published: February 2007

Because previous work found that sustained inhibitory breathing (i.e., low frequency breathing without increased tidal volume) can occur in laboratory animals under conditions of behavioral stress, this study sought to determine whether a comparable respiratory pattern could be observed in ambulatory human subjects in their natural environments. Tidal volume, breathing frequency, and minute ventilation were monitored continuously during 24‐hour sessions via inductive plethysmography and a portable microprocessor. Mean tidal volume and minute ventilation were significantly higher during the daytime than at night for all subjects. However, mean breathing frequency was not consistently higher during the daytime, because episodes of low frequency breathing offset episodes of high breathing frequency. Tidal volume during low frequency breathing was comparable to that observed during medium or high frequency breathing. Thus, low frequency breathing was indicative of low minute ventilation. The eliciting stimuli, physiological concomitants, and relevance to health of this energetically inefficient breathing pattern remain to be determined.
A Developmental Event‐Related Potential Study of Picture Matching in Children, Adolescents, and Young Adults: A Replication and Extension
Authors: Friedman David , Putnam Lois , Ritter Walter , Hamberger Marla , Herman Steven
Published: February 2007

Event‐related potentials were recorded in a developmental study of picture matching using an adaptation of Posner's (1978) letter‐matching tasks. Subjects ranging in age from 6–39 were asked to decide whether two line drawings, presented sequentially, were the same or different on the basis of physical (physical identity), nominal (name identity), or categorical (category identity) criteria. The amplitude of a negativity at 400 ms (Neg400) increased as the number of dimensions on which the two line drawings differed increased. This effect held for all age groups, and was interpreted as reflecting the degree of semantic and/or physical relationship between the two pictures. However, one finding for Neg400 did suggest a qualitative difference in processing mode between the younger and older subjects. Both Neg400 and P3b latencies showed highly significant linear age trends, decreasing with increasing age. These age‐related changes were interpreted as demonstrating quantitative speed of processing differences among age groups. The latencies of both Neg400 and P3b increased as the matching criteria became more complex. Moreover, P3b latency increased as the number of dimensions on which the two pictures differed increased, and this did not interact with age. Although both Neg400 and P3b showed age‐related changes in scalp distribution, the fact that each was related to the experimental variables in similar fashion in all age groups suggested that they were homologous components across the age range studied. Taken as a whole, the data support continuity of information processing during these tasks across a wide age range.
Peripheral thermal responsivity to facial cooling during sleep
Authors: JENNINGS J. RICHARD , REYNOLDS CHARLES F. , BRYANT DAVID S. , BERMAN SUSAN R. , BUYSSE DANIEL J. , DAHL RONALD E. , HOCH CAROLYN C. , MONK TIMOTHY H.
Published: February 2007

A recently developed technique for examining thermal sensitivity during sleep was used to assess whether skin and core temperature responses to thermal stimulation were altered by sleep state. The technique was designed to probe thermal responsivity without altering core body temperature or inducing awakening. Twenty‐seven young men and women were studied during a sleep deprivation night and a sleep night three nights later. Cold water stimulation of the face alternated with an equal period of rewarming across a 40‐min cycle throughout the night. Skin temperature from the finger and rectal temperature were continuously assessed. Sleep continuity and architecture were largely uninfluenced by the thermal stimulation. Finger skin temperature decreased during cold facial stimulation in both sleep and waking states. Skin temperature changes during sleep were approximately one‐fifth the magnitude of those during waking. Core temperature was minimally influenced. REM sleep was associated with a greater amplitude decrease in finger temperature than was non‐REM (NREM) sleep. The results support the utility of the technique as a probe of thermal responsivity during sleep and suggest a reduction of thermal responsivity during sleep and, more tentatively, an altered responsivity during REM versus NREM sleep.
Effects of intermodality change on electrodermal orienting and on the allocation of processing resources
Authors: SIDDLE DAVID A. T. , JORDAN JO
Published: February 2007

Two experiments studied the effects of intermodality change on electrodermal responses and on reaction time to a secondary task probe stimulus after 24 habituation training trials with either a tone or a vibrotactile stimulus. The probe was a visual stimulus of 500 ms duration, and within‐stimulus probes occurred 300 ms following stimulus onset. Experiment 1 crossed change versus no change with modality of the training stimulus. Skin conductance responses (SCRs) were larger in the experimental group than in the control on the test trial, and in the experimental group, test trial responses were larger than those on the first training trial. Probe reaction time was slower on the test trial in the experimental group than in the control, and within‐stimulus probe reaction time was slower than interstimulus interval reaction time early in the habituation series. Experiment 2 crossed change versus no change with the presence of a secondary task. Test trial SCRs were larger in the experimental group than in the control, regardless of whether or not the secondary task was present. In addition, test trial responses in the experimental group were larger than those on the first training trial in both the task and no‐task conditions. Within the task condition, reaction time was slower in the experimental condition than in the control on the test trial. In addition, reaction time in the experimental condition was slower during the change trial than during the first training stimulus. The data provide difficulties for noncomparator theories of habituation and seem to be most easily explained by theories of habituation that emphasize the importance of an extrapolatory process.
Respiratory sinus arrhythmia, cardiac vagal tone, and respiration: Within‐ and between‐individual relations
Authors: GROSSMAN PAUL , KOLLAI MARK
Published: February 2007

Respiratory sinus arrhythmia (RSA) is frequently employed as an intra‐ and interindividual index of cardiac parasympathetic tone, although the relationship of RSA to interindividual differences in cardiac vagal tone remains questionable. Our study examined between‐ and within‐subject relations among RSA, cardiac vagal tone, and respiratory parameters. Twenty‐nine young adults performed two sessions of tasks under no medication and single and double autonomic blockade (intravenously administered propranolol and atropine). Parasympathetic tone was determined from heart period responses to complete vagal blockade. Results indicated the following. Resting RSA does not accurately predict individual differences in cardiac vagal tone. However, RSA and heart period together do predict such individual differences reasonably well. The relationship between individual variations in RSA and vagal tone is not improved by controlling respiratory parameters. Substantial cardiac vagal activity occurs during inspiration, and intraindividual variations in respiratory measures confound the association between RSA and cardiac vagal tone.
Stimulus presentation rate dissociates sequential effects in event‐related potentials and reaction times
Authors: LEUTHOLD HARTMUT , SOMMER WERNER
Published: February 2007

The present study explored the impact of the stimulus presentation rate on sequential effects in event‐related potentials (ERPs) and reaction times (RTs). Random series of equiprobable tones were presented at interstimulus intervals (ISIs) of 1.3, 2.1, and 2.9s. Fast and accurate choice responses to the tones were required. Although sequential effects in RTs were stable across all ISIs, the common first‐order repetition effect in P300 amplitude was only observed at the 1.3‐s ISI and not at the slower presentation rates. This dissociation between the first‐order effects in RTs and ERPs speaks against an explanation of both effects by a common expectancy mechanism. In addition, sequential effects were observed as early as about 100 ms after stimulus onset in the lateralized readiness potential. Together with similar sequential effects in P300 latency, this finding supports a continuous flow model of information processing.
Modulation of event‐related potentials by word repetition: The role of visual selective attention
Authors: OTTEN LEUN J. , RUGG MICHAEL D. , DOYLE MICHAEL C.
Published: February 2007

Event‐related potentials (ERPs) were recorded while subjects viewed visually presented words, some of which occurred twice. Each trial consisted of two colored letter strings, the requirement being to attend to and make a word/non word discrimination for one of the strings. Attention was manipulated by color in Experiment 1, and color and a precue were used in Experiment 2. As in previous ERP studies of word repetition, a positive offset to repeated words developed when both first and second presentations were the focus of attention. In Experiment 2, ERPs showed evidence of positive‐going repetition effects in all conditions in which at least one of the two presentations of the repeated word was attended. In the visual modality, the positive‐going ERP repetition effect occurs only when at least one of the two presentations of a repeated item is the object of attention, which suggests that one or more of the processes reflected by the effect is capacity limited.
Postural stability of hemodynamic responses during mental challenge
Authors: SHERWOOD ANDREW , TURNER J. RICK
Published: February 2007

Laboratory stress testing is typically conducted while subjects are seated, whereas real‐life stressors may often be encountered while standing. The present study of 20 healthy young men evaluated blood pressure and underlying hemodynamic adjustments to a standardized mental arithmetic task performed twice while seated and twice while standing. Blood pressure increased during mental arithmetic in both postures, but the underlying hemodynamic determinants of the pressor responses were different for the two postures. Augmented cardiac output was responsible for increasing blood pressure during seated task performance, whereas increased vascular resistance was the mechanism for the pressor response to the task performed while standing. Blood pressure and hemodynamic responses were reproducible subject characteristics for a given posture; test‐retest correlations were significant for all cardiovascular measures. However, seated blood pressure responses were not significantly correlated with standing blood pressure responses. In contrast, significant between‐posture correlations were found for cardiac output and vascular resistance responses. This preliminary evidence of postural stability of the hemodynamic determinants of blood pressure responses during stress is consistent with growing evidence that hemodynamic response tendencies are robust characteristics of reactivity. Ambulatory monitoring of hemodynamic response patterns during real‐life stress may reveal more idiosyncratic profiles of stress reactivity than are displayed by blood pressure responses alone.
Looking at pictures: Affective, facial, visceral, and behavioral reactions
Authors: LANG PETER J. , GREENWALD MARK K. , BRADLEY MARGARET M. , HAMM ALFONS O.
Published: February 2007

Colored photographic pictures that varied widely across the affective dimensions of valence (pleasant‐unpleasant) and arousal (excited‐calm) were each viewed for a 6‐s period while facial electromyographic (zygomatic and corrugator muscle activity) and visceral (heart rate and skin conductance) reactions were measured. Judgments relating to pleasure, arousal, interest, and emotional state were measured, as was choice viewing time. Significant covariation was obtained between (a) facial expression and affective valence judgments and (b) skin conductance magnitude and arousal ratings. Interest ratings and viewing time were also associated with arousal. Although differences due to the subject's gender and cognitive style were obtained, affective responses were largely independent of the personality factors investigated. Response specificity, particularly facial expressiveness, supported the view that specific affects have unique patterns of reactivity. The consistency of the dimensional relationships between evaluative judgments (i.e., pleasure and arousal) and physiological response, however, emphasizes that emotion is fundamentally organized by these motivational parameters.
Automated physical activity monitoring: Validation and comparison with physiological and self‐report measures
Authors: PATTERSON STEPHEN M. , KRANTZ DAVID S. , MONTGOMERY LESLIE C. , DEUSTER PATRICIA A. , HEDGES SUSAN M. , NEBEL LINDA E.
Published: February 2007

Physical activity can be assessed via self‐report, via physiological measures such as heart rate and oxygen uptake, or via automated monitor. An electronic accelerometer‐based physical activity device (Actigraph) has been reported as an improvement over other activity measurement techniques in terms of utility and accuracy. Four studies provide systematic validation and reliability testing for this device and comparisons with other techniques for assessing daily activities. In the first study, the sensitivity of the Actigraph was determined for differentiating physical activities (walking, running, stair climbing, knee bends) versus sedentary activities (reading, typing, playing video games, and performing a mental arithmetic task). Fifteen healthy adults wore the Actigraph on their wrist during activities; oxygen uptake and heart rate were simultaneously recorded. Results revealed that the Actigraph significantly differentiated between the physical activities (p < .0001) and the sedentary activities (p < .0001). Actigraph counts also correlated significantly with oxygen uptake (r= .73) and heart rate (r= .71) during physical activities (r= .46) and sedentary activities (r= .35), respectively. Test‐retest reliability was very high for 12 activities (r= .98). The high level of activity differentiation and strong relationship to oxygen uptake and heart rate suggest the usefulness of this device for behavioral and biomedical studies. However, these studies also indicate that the wrist may not always be the most adequate placement for indexing rate and intensity of daily activities and that further studies are needed to determine the optimal site of monitor attachment. Advantages and disadvantages of self‐report, physiological, and automated measures of activity are discussed.
Parasympathetic nervous system control of heart rate responses to stress in offspring of hypertensives
Authors: MILLER SYDNEY B.
Published: February 2007

The elevated heart rate response to stress in normotensive offspring of hypertensives (PH+) has been suggested to be a function of sympathetic nervous system activity. This study examined whether parasympathetic nervous system activity may also underlie familial differences in the heart rate response. Twenty‐four subjects, half of whom were PH+, were exposed to four stressor tasks administered in counterbalanced order. Stressors were chosen based on previous research that suggested vagal contributions to the heart rate response. Stressors were a cold pack to the forehead, isometric hand grip, a noxious film, and a shock‐avoidance video game task. Physiological measures included heart rate (HR), respiration rate (RR), and respiratory sinus arrhythmia (RSA). RSA values were corrected for corresponding RR by analysis of covariance. Familial differences in HR were observed in response to the hand grip and video game tasks. However, in both cases analyses suggest that familial differences in reactivity were a function of primarily sympathetic as opposed to parasympathetic influences. Familial differences in RSA were not observed for rest or tasks. This study found no evidence for parasympathetic mediation of familial differences in the heart rate response to the stressors employed.
Cardiac vagal tone and sustained attention in school‐age children
Authors: SUESS PATRICIA E. , PORGES STEPHEN W. , PLUDE DANA J.
Published: February 2007

Three hypotheses tested relationships between cardiac responses mediated via the vagus and sustained attention in a population of normal school‐age children. These hypotheses addressed the theoretical relationships among resting cardiac vagal tone (using the Porges estimate of respiratory sinus arrhythmia, V), performance measures of sustained attention, and cardiac reactivity during sustained attention. Thirty‐two fourth and fifth grade children performed a continuous performance task while their electrocardiograms were monitored. Children with higher resting levels of V performed better on the first 3‐min block of the continuous performance task. Additionally, levels of V were significantly reduced across the blocks of the 9‐min task for all children. No relationships were found between resting levels of V and change in either V or heart period during task performance. These findings support two of the three hypotheses proposed by Porges regarding individual differences in cardiac vagal tone and sustained attention.