bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Arousal on Habituation of the Electrodermal Orienting Reflex
Authors: Goldwater B. C. , Lewis J.
Published: February 2007

The effect of level of arousal upon rate of habituation of the electrodermal orienting reflex (OR) was studied by having 20 tone stimuli presented while subjects were either standing or seated. The standing condition was characterized by both a higher heart rate (HR) and a greater frequency of spontaneous skin resistance responses (SRRs). Compared to standing subjects, subjects under the seated condition demonstrated more rapid habituation of the OR as indicated both by a greater decrement in SRR frequency from the first to the last block of trials and by a greater proportion of subjects who failed to respond to any of the last 10 trials. The rate of spontaneous SRRs appeared to parallel these differences in habituation of evoked responses. There were no differences between groups in skin conductance level (SCL), or in either amplitude or frequency of the evoked electrodermal response over the first few stimulus presentations. The results were interpreted as supporting the conclusion that heightened arousal level retards habituation of the OR.
Changes in Heart Rate, Muscle Activity, and Anxiety Level Following Shock Threat
Authors: Petry Heywood M. , Desiderato Otello
Published: February 2007

Variations in HR, forearm EMG, and anxiety level were recorded over a 6‐min interval scheduled to end with an electric shock. Sixty subjects were divided equally among four groups. Only two of the groups could watch a clock while waiting for the shock; the other two had no clock available. One group in each of these two conditions gave verbal reports of anxiety at various times while waiting for the shock. The results showed an increase in HR at the end of the anticipation interval in the two Clock groups, and no such rise in the two No Clock groups. Very similar results were found for anxiety level, but not for forearm EMG. These findings suggest that HR increases during anticipation of shock reflect a rising anxiety level, rather than a concomitant increase in muscle activity.
Constraints on Measuring Heart Rate and Period Sequentially Through Real and Cardiac Time
Authors: Graham Frances K.
Published: February 2007

It is generally assumed that either heart rate or heart period can be used to measure phasic cardiac activity changing either from beat to beat or from second to second. However, only rate analyzed in real‐time units and only period analyzed in cardiac‐time units have the important property that the arithmetic mean of the unit estimates is free to vary and yields an average equal to the definitional estimate based on all units.
Prediction of the Informational and Motivational Properties of “Right‐Wrong” Knowledge of Results With the Skin Resistance Response
Authors: Grilly David M.
Published: February 2007

The magnitude and rate of habituation of the skin resistance response (SRR) to extrinsic “right‐wrong” knowledge of results (KR) were used to assess the KR's motivational and informational properties in delayed matching of visual patterns. Two experimental groups of 20 college students each received KR which was either contingent or non‐contingent upon their actual choices, and two control groups of 10 subjects each received no KR. The magnitude of the SRR elicited was found to be higher to “right” than “wrong” KR stimuli but was not affected by correctness of the subjects' choices. The relative rate of SRR habituation was rapid when a low frequency of “right” KR stimuli was provided and the KR stimuli were not contingent upon the subjects' choices, but it was slow if either a high frequency of “right” KR stimuli were provided or the KR stimuli were contingent upon the subjects' choices. The results indicated that the KR stimuli had motivational properties but very little informational value. It was concluded that the SRR may be useful in assessing the reinforcing value of a feedback stimulus in terms of its motivational and informational qualities independently from its effects on task performance.
Lateralized Facial Muscle Response to Positive and Negative Emotional Stimuli
Authors: Schwartz Gary E. , Ahern Geoffrey L. , Brown Serena‐Lynn
Published: February 2007

Facial electromyography (EMG) was recorded from left and right zygomatic and corrugator muscle regions in response to reflective questions and during voluntary facial expressions. Both muscle regions showed consistent responses to five emotions (happiness, excitement, neutral, sadness, and fear) evoked in the involuntary condition (i.e. reflective questions) and four emotional facial expressions (happiness, excitement, sadness, and fear) self‐generated in the voluntary condition. Lateralized responses were found for the zygomatic muscle in the involuntary condition: positive emotion questions elicited relatively greater right muscle activity than left muscle activity, while negative emotion questions elicited relatively greater left muscle activity than right muscle activity. Lateralized responses were found for the corrugator muscle in the voluntary condition, but were not significantly related to type of emotional expression. Sex differences indicating greater lateralization for females were found in some of the measures. The results are consistent with the hypothesized specialization of the left and right cerebral hemispheres for the mediation of positive and negative emotions, respectively.
Autonomic and Affective Reactions of High and Low Socially‐Anxious Individuals Awaiting Public Performance
Authors: Knight Martha L. , Borden Richard J.
Published: February 2007

The physical threat anticipation paradigm was modified for the study of anticipatory social anxiety responses. It was found that heart rate (HR) and skin conductance (SC) responses during anticipation of a socially threatening event (i.e., public speaking) were similar to those occurring prior to physical threat, with the largest changes taking place during the final portion of anticipation. Likewise, self‐reports of cognitively experienced nervousness displayed a positively accelerating pattern of increase as the time of performance approached. The present findings suggest a psychological time‐division process, such that the anticipation interval consists of an initial waiting period, followed by a briefer period of active preparatron.

During the anticipation interval high and low socially‐anxious subjects displayed similar HR and SC responses, but differed significantly in patterns of finger pulse volume (FPV) and self‐reported nervousness. As performance became imminent, high socially‐anxious subjects evidenced increased vasoconstriction and reported greater nervousness than low socially‐anxious subjects.

Taken together, these results indicate that, irrespective of psychometrically assessed anxiety, and/or type of threatening stimulus, the autonomic patterns during anticipation of threat are characterized by accelerating responsiveness. Thus, the temporal parameter of the anticipation situation (i.e., remaining time) is the primary determinant of reactions while awaiting threat.
The Modality Specificity of the Slow Negative Wave
Authors: Ritter Walter , Rotkin Laurence , Vaughan Herbert G.
Published: February 2007

Event‐related potentials were recorded in a simple reaction time task using a 3‐sec interval between S1 and S2. The sensory modalities of S1 and S2 were varied across 4 conditions to yield all possible combinations of tones and flashes. A negative component which peaked between 600 and 800 msec after S1 was specific in scalp distribution to the modality of S1 but not S2. It was concluded that this negative component is a response to S1 and not related to processes associated with anticipation of S2. A slow negative shift which peaked at S2 was largest at the vertex in all conditions, suggesting its motor origin. A trend for the latter activity to be more negative in posterior recordings when S2 was visual than auditory leaves open the possibility that the terminal CNV is a combination of motor activities and anticipation of the sensory modality of S2.
Cardiovascular Response to Stress: Effects of Opportunity to Avoid, Shock Experience, and Performance Feedback
Authors: Light Kathleen C. , Obrist Paul A.
Published: February 2007

The cardiovascular effects of three factors related to active coping were examined during an unsignaled reaction time (RT) task involving exposure to mild shocks. These factors were the opportunity to avoid shocks contingent on performance, prior experience with the shock, and the availability of performance feedback. A yoked control design was used to ensure that shocks were delivered to avoidance and no‐avoidance subjects on the same schedule. All subjects initially showed substantial increases in systolic blood pressure (SBP) and both cardiac rate and performance, but these diminished later in the task. Subjects who could avoid shocks showed greater changes in SBP, heart rate (HR), and pulse transit time (PIT) than those passively exposed to shocks. Lack of prior experience with the shock augmented changes in HR, PTT and carotid dP/dt, but the HR increase was no longer reliable after the first 2 min when all subjects had experienced the shock. For subjects who could control the task by avoiding shocks, providing performance feedback had no effects. For no‐avoidance subjects, providing feedback led to changes in SBP and PTT which were significantly greater than those shown by the subjects without feedback. These findings are consistent with the hypothesis that characteristics which increase active coping efforts evoke greater sympathetically mediated cardiovascular changes.
Some Remarks on the Development of a Standardized Time Constant
Authors: Elbert Thomas , Rockstroh Brigitte
Published: February 2007

A method is provided to estimate the original event‐related potential waveshapes from data obtained by filtering with different time constants. As is shown, even averaged data can be transformed easily. It is suggested that investigators recording with time constants present transformed DC data as further information.
Electromyographic Specificity During Covert Information Processing
Authors: Cacioppo John T. , Petty Richard E.
Published: February 2007

Subjects performed tasks of rhyme, volume‐discrimination, association, evaluation, and self‐reference for verbal stimuli. The stimuli and overt response (pressing one of two microswitches) were constant across tasks and subjects. Oral and nonoral electromyographic (EMG) and cardiac activity were monitored continuously. We found that the depth of processing was associated with enhanced EMG activity of the speech muscles, but was unrelated to cardiac and nonoral EMG activity. Moreover, this association was observed only when subjects were covertly analyzing the stimuli. It was concluded that the pattern of perioral EMG activity can reflect the extent to which encoding operations are directed toward meaning.
Cardiovascular Responses to Effortful Active Coping: Implications for the Role of Stress in Hypertension Development
Authors: Light Kathleen C.
Published: February 2007

Recent contributions to the literature on stress and hypertension are discussed. The significance of effortful active coping in evoking sympathetically‐mediated heart rate and blood pressure increases is supported by results of studies involving both aversive and appetitive task incentives. Young healthy males who are above‐average in heart rate during coping tasks show consistently higher heart rates and systolic pressures during other stresses as well, but are indistinguishable from less reactive persons when relaxed. Studies involving beta‐blockade indicate that these above‐average cardiovascular increases are partly due to a greater beta‐adrenergic response among the high heart rate reactors. In addition, the parents of these high heart rate reactors report a greater incidence of hypertension than parents of low reactors, suggesting that high cardiovascular responses during active coping stress may reflect a high degree of susceptibility to later hypertension.
Neuroanatomical and Physiological Foundations of Extraversion
Authors: Campbell Kenneth B. , Baribeau‐Braün Jacinthe , Braün Claude
Published: February 2007

Two auditory brainstem evoked potential studies were carried out to investigate the role of sensory influences, independent of factors such as attention and arousal, in groups varying in extraversion. In the first experiment, the rate of stimulus presentation was either 11, 41 or 81 clicks/sec, stimulus intensity being held constant at 70dB above the threshold of a normal young adult sample. Neither the latency nor the amplitude of any of the brainstem components significantly differed among the introverted, ambiverted or extraverted groups for any rate of presentation. In the second experiment, repetition rate was either 41 or 81 clicks/sec and intensity established at 20, 30, 50 and 70 dB. Peak V showed a highly consistent and significant increase in latency and decrease in amplitude with decreasing intensity. Again, however, no inter‐group differences were found. The results suggest that N1‐P2 effects that have been found at higher levels of the brain are probably not due to parallel changes in the periphery or the brainstem. The possibility that non‐sensory factors, such as attention and motivation, might have accounted for these cortical differences is also discussed.
Sympathetic Skin Nerve Discharges in Relation to Amplitude of Skin Resistance Responses
Authors: Lidberg Lars , Wallin B. Gunnar
Published: February 2007

Sympathetic skin nerve action potentials were recorded in the median nerve of 5 healthy college students. A linear and significant correlation was found between the mean voltage amplitude of the sympathetic bursts and the amplitude of skin resistance responses (SRRs). Thus amplitude of skin resistance responses seems to be an index of sympathetic activity.
An R‐wave Simulator for Testing and Calibrating Heart Rate Amplification and Processing Systems
Authors: Harbin Thomas J. , Berg W. Keith
Published: February 2007

A simple, inexpensive device described here will produce a spike whose amplitude, shape, and output impedance are similar to those of the human QRS complex. Several reliable spike rates can be selected.
On the Language and Logic of Psychophysiology: A Reply to Donchin
Authors: Schwartz Marvin , Pritchard Walter
Published: February 2007

Donchin's critique of the paper by Schwartz and Pritchard illustrates several common faults in the use of language and logic. These include:

1. Inconsistent use of language and confusion in the use of theoretically meaningful terms;

2. The confusion of psychological and physiological domains, i.e., the use of psychological constructs as “explanations” in physiological theory and vice versa;

3. The tendency to be selective of data and explanations “justifying” a particular theoretical orientation without establishing criteria for the selections.

For the study of electrical responses of the human brain to have significance for understanding information processing, theories must be founded in logical and consistent use of language, according to explicit decision criteria.
Pupillary Dilation as an Index of the Orienting Reflex
Authors: Stelmack Robert M. , Siddle David A. T.
Published: February 2007

The effects of tone intensity (60, 75, or 90 dB) on the amplitude and habituation of the pupillary dilation response were investigated using a between‐groups design (N = 72). Although pupillary dilation responses were elicited in all intensity conditions, neither response amplitude nor habituation was influenced by differences in stimulus intensity, and the response was insensitive to changes in intensity following the habituation series. Eighteen subjects in the 90dB group were retested and the reliability of the response was found to be low. In Experiment 2 (N = 30), the variability of pupillary activity was reduced with a low level of background illumination, but overall test‐retest reliability of the dilation response to 90dB tones was low. The insensitivity of the response to intensity manipulations, the rapid development of habituation, and the low test‐retest reliability of the response are clear limitations on the usefulness of the pupillary dilation response as an index of the orienting reflex to nonsignal stimulation.
Interactive Effects of Stimulus Probability and Significance on the Skin Conductance Response
Authors: Ben‐Shakhar Gershon , Lieblich Israel , Kugelmass Sol
Published: February 2007

The present study deals with the effects of stimulus significance and stimulus probability on skin conductance responses (SCRs). Eighty subjects (“informed” group) chose a numbered card, and 60 subjects (“uninformed” group) chose a blank card. All subjects were presented with a series of stimuli in the form of questions about numbers. The relative frequencies of the relevant (chosen) numbers were manipulated. The results showed expected effects of stimulus relevance and stimulus probability on SCRs. A more interesting result was an interaction of stimulus significance and relative frequency, meaning that the probability effect (greater responsivity to the less frequent stimulus) was stronger when the series of stimuli was comprised of relevant and neutral stimuli, than when two different neutral stimuli were used. This latter result was interpreted in terms of generalization of habituation. It was suggested that the relevance manipulation interferes with the generalization of habituation process.
Extraversion and Multiple Levels of Caffeine‐Induced Arousal: Effects on Overhabituation and Dishabituation
Authors: Smith Barry D. , Wilson Raymond J. , Jones Bruce E.
Published: February 2007

Psychophysiological tests of the Eysenck hypothesis that introverts are more arousal prone than extraverts have yielded somewhat mixed results. In an attempt to clarify and extend previous findings, the present study manipulated arousal level, using caffeine. Extreme groups of 48 extraverts and 48 introverts were used, and each subject was randomly assigned to a low, medium, or high dosage of caffeine or a placebo. Each subject heard a series of tones until criterion electrodermal habituation occurred. This was followed by dishabituation, overhabituation, and a further dishabituation procedure. Increasing caffeine dosages produced a linear increment in tonic levels in extraverts, but had little effect on SCL in introverts. Higher caffeine dosages also increased phasic response amplitudes in extraverts but decreased amplitudes in introverts. Although somewhat complex, results were partially supportive of the Eysenck hypothesis.
An Arterial to Peripheral Pulse Wave Velocity Measure
Authors: Jennings J. Richard , Choi Samuel
Published: February 2007

Optical pulse transducers (photoplethysmographs) provide convenient measures of pulse wave velocity (PWV). If measured between arterial and arteriolar sites, PWV should be a sensitive index of sympathetic nervous system influences on the vasculature. Evidence of such a sensitivity was found in a study of rats in which vasoactive drug reactions simulated changes in sympathetic activity. Application of arterial to arteriolar PWV in humans further required the definition of optimal points on the two waveforms to be used in velocity calculations. An examination of different PWV indices supported use of a foot‐to‐foot index. Overall, our results support the promise of optical PWV techniques, but do not yet establish its validity as an index of peripheral sympathetic influences.
Respiration, Stress, and Cardiovascular Function
Authors: Grossman Paul
Published: February 2007

The significance of respiratory influences upon cardiovascular functioning has been much neglected in the psychophysiological literature. Various phasic and nonphasic respiratory parameters manifest marked and specific effects upon numerous cardiac and circulatory events. Ventilatory patterns associated with stress responses, furthermore, bring about cardiovascular alterations indicative of dysfunction and risk, even when these ventilatory patterns are voluntarily enacted by normal individuals under nonstressful circumstances. Evidence is presented which suggests that respiratory processes may contribute significantly to cardiovascular competence and dysfunction. The implications of this theoretical approach for psychophysiological research are also discussed.
EEG Changes During Tobacco Withdrawal
Authors: Herning Ronald I. , Jones Reese T. , Bachman John
Published: February 2007

Tobacco smoking decreases theta and alpha power and increases the dominant alpha frequency in smokers deprived of cigarettes for 10‐17 hrs. The slow alpha frequency in deprived smokers has been attributed to either (1) characterological differences between smokers and nonsmokers, or (2) nicotine withdrawal. Studies finding slower alpha in deprived smokers were not able to replicate previous findings of decreased alpha abundance after smoking, nor did they consider the importance of increased theta as a withdrawal sign. We studied 11 smokers for one day and 7 smokers for two days while they smoked a series of placebo and nicotine cigarettes. Theta and alpha power increased with tobacco deprivation but were decreased for 30‐90 min by nicotine cigarettes. The dominant alpha frequency in deprived smokers was slower than after smoking a nicotine cigarette, but the decreases in frequency were not always statistically significant.
Changes in Heart Period, Heart Period Variability, and a Spectral Analysis Estimate of Respiratory Sinus Arrhythmias During Aortic Nerve Stimulation in Rabbits
Authors: McCabe Philip M. , Yongue Brandon G. , Porges Stephen W. , Ackles Patrick K.
Published: February 2007

Changes in heart period, heart period variance (HPV), and the respiratory component of HPV were examined during enhanced negative chronotropic influences on the heart produced by aortic depressor nerve (ADN) stimulation in urethane anesthetized rabbits. Spectral analysis was used to quantify the respiratory component of HPV, respiratory sinus arrhythmia (RSA). The statistic derived from spectral analysis which describes RSA, V̂, has been proposed to be sensitive to vagal influences on the heart. Stimulation of the ADN significantly increased V̂, heart period, and HPV. However, unlike V̂ and heart period, HPV values remained elevated following the end of stimulation. Propranolol administration did not alter the magnitude of the evoked increase in V̂, heart period, or HPV. In contrast, administration of atropine abolished the increases due to stimulation in all three measures. Heart period exhibited a monotonic relationship with stimulation current intensity. This relationship disappeared after propranolol administration suggesting sympathetic mediation. The results suggest that V̂ is sensitive to manipulations of vagal influences on the heart. In addition, V̂ often responds in a different manner from heart period and HPV.
The Electrodermal Orienting Response and Memory: An Analysis of Age Differences in Picture Recall
Authors: Plouffe Louise , Stelmack Robert M.
Published: February 2007

Young and elderly women were compared on electrodermal measures of the orienting response (OR) to picture stimuli presented during the study phase of a free recall task. Responses were also recorded during a subsequent simple habituation paradigm which was designed to investigate stimulus priming effects. Young subjects recalled more pictures than the elderly and both groups remembered more pictures with common word names than pictures with uncommon verbal labels. Young and older subjects displayed larger skin conductance responses to recalled pictures, especially to recalled uncommon pictures. Older women, however, displayed consistently smaller SCRs than the young. Stimulus priming was observed on the first trial of habituation training where not‐recalled pictures evoked smaller SCRs than pictures not shown in the study phase. There were no age differences in habituation across trials. In general, the results indicated that the electrodermal OR is functionally related to recall performance and that the age decrement in recall may be attributed to reduced cognitive effort in the elderly.
The Detection of Sleep Onset: Behavioral and Physiological Convergence
Authors: Ogilvie Robert D. , Wilkinson Robert T.
Published: February 2007

Reaction time (RT), a behavioral measure of arousal, was used to examine standard criteria (Rechtschaffen & Kales, 1968) for assessing sleep onset (SO) and the sensitivity of changes in respiratory patterns at SO. Following 24 hrs without sleep, RT, respiratory, and EEG measures were used to study SO in 12 subjects. Sleep deprivation (SD) permitted multiple examinations of SO in 2 daytime testing periods. Strong relationships between RT and EEG‐based measures of SO serve to confirm the distinction between wakefulness and stage 1 sleep, and moderate to weak correlations between RT and respiratory indices describe the usefulness of the latter.

Behavioral, respiratory and EEG assessments of the shift from wakefulness to sleep were observed to be orderly and rapid in these SD volunteers, suggesting that the detection of SO could be sharpened by adding behavioral and respiratory measures to the usual EEG criteria. The close temporal correspondence among these changes has interesting implications for sleep/waking mechanisms.
The Effects of Fatigue and Task Repetition on the Surface Electromyographic Signal
Authors: Mulder Theo , Hulstijn Wouter
Published: February 2007

The effects of fatigue and repetition of the task on the surface electromyographic signal were examined during 4 sessions using an isometric motor control task. The muscle chosen for this study was one of the main ankle dorsiflexors (m. tibialis anterior). The electromyographic output and a functional (force) output of this muscle were recorded during two conditions: a SHORT‐F condition in which the effect of task repetition on the relationship between force and IEMG was studied, and a LONG‐F condition in which the effect of fatigue was studied. The results indicated that repetition of the task resulted in a significant increase in the ratio between the electromyographic and functional output of the m. tibialis anterior, indicating an increase in efficiency across the 4 sessions. Fatigue on the other hand resulted in a significant decrease in the ratio between the electromyographic and functional output of the m. tibialis anterior, indicating a decrease in efficiency. Fatigue also resulted in a significant and rapid increase in the electromyographic activity. The implications of these results for the therapeutic use of the electromyographic signal were discussed.
Laterality of 40 Hz EEG and EMG During Cognitive Performance
Authors: Loring David W. , Sheer Daniel E.
Published: February 2007

Task‐dependent lateralization of the 40 Hz EEG rhythm was investigated in 15 right‐handed male adults during the performance of verbal analogy and geometric figure rotation tasks. Forty Hz EMG recorded from the temporal and splenius muscles was similarly examined. Results indicate that 40 Hz EEG is asymmetrically distributed during cognitive performance, varying as a function of cognitive processsing. The range of laterality scores also varied by condition, with the largest variation present during baseline conditions and smallest recorded during the presentation of the verbal analogies task, suggesting that individual cognitive styles tend to vary more during less structured situations. No relationship between 40 Hz EMG and task was obtained.
Awareness of Heart Activity and Self‐Control of Heart Rate: A Failure to Replicate
Authors: Young Larry D. , Blanchard Edward B.
Published: February 2007

The present report describes our failure to replicate a previously reported relationship between heart rate self‐control and self‐reported awareness of cardiac activity using nearly identical methods within the same population. The implications of this failure‐to‐replicate are noted.
Response Initiation, Not Completion, Seems to Alter Cardiac Cycle Length
Authors: Somsen R.J.M. , van der Molen M.W. , Jennings J.R. , Orlebeke J.F.
Published: February 2007

The effects on cardiac interbeat interval (IBI) length of the initiation and completion of speeded motor reactions were examined at different points in the cardiac cycle (different times after the Rwave of the electrocardiogram). Stimuli were presented either at the R‐wave or 350 ms afterward. Responses were paced by instructions to release a start key prior to three different target times (150, 275, or 500 ms). Initiation time was defined as the interval between stimulus onset and the release of the start key; completion time was defined as the interval between the onset of the stimulus and the depression of one of two response keys. The shift from anticipatory deceleration to acceleration varied systematically as a function of time of response relative to the R‐wave. Responses that occurred early in the cardiac cycle were associated with a shift from deceleration to acceleration in the same IBI; for late occurring responses the shift occurred in the subsequent IBI. Most importantly, when response initiation occurred early in the cycle (<300 ms) and response completion occurred late, deceleration was terminated during the same IBI. Initiation rather than completion seems to control the inhibitory vagal input to the heart that is responsible for anticipatory deceleration.
Psychophysiological Responsiveness to Auditory Stimulation during Transcendental Meditation
Authors: Heide Frederick J.
Published: February 2007

The Transcendental Meditation (TM) technique has been reported to produce cortical states of both steady responsiveness and lack of responsiveness to external stimulation during meditation. The present study examined alpha blocking, skin conductance, and phasic heart rate response to 80dB tones in 17 TM meditators and 17 controls. There were no significant differences between groups in rate of habituation of alpha blocking or skin conductance response, and neither group showed habituation of heart rate responding. Controls displayed a more labile and accelerative cardiac response. Results suggest the possible usefulness of cardiac waveform activity in the study of meditation.
Heart Rate and Oxygen Consumption during Active Psychological Challenge: The Effects of Level of Difficulty
Authors: Carroll Douglas , Rick Turner J. , Hellawell Jonathan C.
Published: February 2007

Heart rate and various metabolic and ventilatory indices were monitored while 24 young males engaged in two psychologically challenging tasks, mental arithmetic and Raven's matrices. Each task was structured to present subjects with three levels of difficulty: easy, hard, and impossible. Measurements were also made while subjects undertook graded isotonic exercise on a bicycle ergometer; for each subject, heart rate was plotted against oxygen consumption over the various exercise loads. Knowing oxygen consumption during the psychological tasks, these regression equations permitted the calculation of expected heart rates during each task condition, and thus the computation of ‘additional heart rate’ as the difference between actual and predicted heart rate values. Cardiac activity, whether represented as additional heart rate or as the difference between resting and task heart rate levels, was sensitive to variations in difficulty level. In both tasks the easy condition elicited significantly less cardiac activity than both the hard and the impossible conditions. Changes in oxygen consumption and carbon dioxide production did not vary significantly with difficulty. Subjects' self‐reports of active engagement and arousal paralleled the cardiac effects; in both tasks the easy condition was experienced as relatively unengaging and unarousing.
Interactions of Respiratory and Cardiovascular Adjustments to Behavioral Stressors
Authors: Allen Michael T. , Sherwood Andrew , Obrist Paul A.
Published: February 2007

The relationships among a variety of cardiovascular and respiratory measures were examined in young college males subjected to a cold pressor task, reaction‐time shock avoidance task, and three levels of graded exercise. As expected, the relationships between cardiovascular (e.g., heart rate and cardiac output) and respiratory (e.g., oxygen uptake and minute ventilation) variables were tightly linear when considering rest and exercise values. However, the range of individual cardiopulmonary responses during cold pressor and reaction time was considerable, often leading to disruptions in the cardiovascular/respiratory interactions. Analyses of extreme high and low ventilation reactors during both reaction time and cold pressor revealed that the excessive ventilation responders in cold pressor showed clear signs of hyperventilation. Increases in ventilation by the high reactors during reaction time were of smaller magnitude than during cold pressor, with potential hyperventilation much less clear. Increases in minute ventilation by reactors during the cold pressor task were primarily due to large increases in tidal volume, with only modest increases in respiratory rate. For reaction time, however, the increases in ventilation by reactive individuals stemmed from rate increases with tidal volume remaining essentially unchanged.
Greater Resistance to Extinction of Electrodermal Responses Conditioned to Potentially Phobic CSs: A Noncognitive Process?
Authors: Dawson Michael E. , Schell Anne M. , Banis Heather Tweddle
Published: February 2007

Previous results have suggested that electrodermal responses classically conditioned to potentially phobic CSs (e.g., pictures of snakes or spiders) are highly resistant to extinction and occur largely independently of cognitive expectancies. In order to test stringently for these possibilities, 144 college student subjects were administered differential classical conditioning acquisition and extinction paradigms while expectancies of the shock UCS were closely monitored. Half the subjects had potentially phobic CSs, whereas the other half had neutral CSs. Regardless of type of CS, during acquisition no evidence of electrodermal conditioning was found among subjects unaware of the CS−UCS contingency, nor was conditioning found on the pre‐aware trials of subjects who became aware. During extinction, there was significantly greater resistance to extinction of electrodermal responses conditioned to potentially phobic CSs as well as a similar trend with expectancies of the UCS. However, when expectancies were equated, there was no greater resistance to extinction of electrodermal responses conditioned to potentially phobic CSs. Thus, while electrodermal responses conditioned to potentially phobic CSs did exhibit greater resistance to extinction, this conditioning was no more independent of expectancies than is conditioning with neutral CSs.
Sex Differences in Physiological Reactions to Real Life Stress and Their Relationship to Psychological Variables
Authors: van Doornen Lorenz J.P.
Published: February 2007

The present experiment investigates whether there are sex differences in physiological reactions to real life stress and whether these reactions are differentially related to psychological variables in males and females. In 29 male and 23 female students physiological measurements were taken on the day of an examination and on a normal routine day. Behavioral characteristics were measured using questionnaires. Serum cholesterol level, systolic blood pressure, and heart rate were found to be higher on the examination day. These reactions did not differ between the sexes. Males showed a larger increase of urine‐adrenaline excretion than did females. In males, cholesterol level and response were related to achievement motivation. Ambulatory monitored HR during the exam correlated with state anxiety and state depression in females, but not in males. The analysis of sex specific expression of behavioral traits in physiological parameters, including the CHD risk factors, is of potential value for a better understanding of mechanisms mediating between behavior and CHD risk.
ERPs to Laterally Presented Pictures and Words in a Semantic Categorization Task
Authors: Kok A. , Rooyakkers J. A. J.
Published: February 2007

Event‐related potentials (ERPs) were recorded from subjects reacting to visual stimuli (pictures or words) presented in the left and right visual fields. Subjects were instructed to match these stimuli on the basis of physical or categorical identity with stimuli of a previously presented memory list. The ERPs elicited by the lateral stimuli consisted of a sequence of topographically and functionally separable, negative and positive components, including N200, P300, N540, P720, and SW. On left and right hemispheric locations N200 was consistently larger, and P720 consistently smaller to stimuli presented in the contralateral fields than to stimuli presented in the ipsilateral fields. In addition, the amplitude of P720 to ipsilaterally presented stimuli showed a marked variation in amplitude as a function of stimulus type, level of practice, and the hemispheric site of measurement, while contralaterally presented stimuli produced only minimal variation in P720 amplitude. The latter results are discussed in relation to possible intracranial sources and the functional significance of the P3 component elicited by laterally presented stimuli.
Another Look at the Relationship of Electrodermal Activity to Electrode Contact Area
Authors: Mahon Mary L. , Iacono William G.
Published: February 2007

The present study was undertaken lo reexamine the hypothesis that the relationship between skin conductance and electrode size is monotonic and linear. Skin conductance activity was recorded from 48 right‐handed male subjects using 6 different sixes of electrode collars ranging in exposed surface area from .131 cm2 to .786 cm2. The dependent measures were skin conductance level (SCL); skin conductance response (SCR) amplitude to a series of 8 loud tones; latency, rise time, and recovery half‐time of the first tone elicited response; (he largest self‐generated SCR; and the number of nonspecific responses. The results indicated a significant linear relationship between contact area and SCL, stimulus and self‐generated SCR amplitude, and the number of nonspecific responses. Latency was not affected by electrode size although the other time‐based measures were. Differences in skin conductance activity were found among different palmar recording sites. The observed linear relationship between electrode size and electrodermal measures has implications for current models of electrodermal activity and for the comparison of results across studies in which different electrode contact areas are used.
Contrasting Effects of Response Uncertainty on the Task‐Evoked Pupillary Response and Reaction Time
Authors: Richer Francois , Beatty Jackson
Published: February 2007

The effects of response uncertainty on pupillary and reaction time measures of processing load were compared during choice reactions. Subjects performed simple, two‐choice, and four‐choice reaction time tasks in which Go and/or NoGo responses were required, holding stimulus probability constant. In Go trials, pupillary response amplitude increased with increasing number of response alternatives, in conditions involving one, two, or four Go responses whether Go or NoGo responses were used as alternatives. The amplitude of dilations to Go responses was almost linearly related to response uncertainty, whereas the increase in response latency showed the usual decelerating function. In NoGo trials, pupillary response amplitude was also inversely related to the probability of individual Go responses. Results are interpreted in terms of a differential sensitivity of pupillary and behavioral measures to the introduction of decisional demands in the task.
Shortened REM Latency: Consequence of Psychological Strain?
Authors: Lauer C. , Riemann D. , Lund R. , Berger M.
Published: February 2007

Previous research has demonstrated that in healthy subjects sit uat ional strain may provoke not only sleep disturbances characteristic of depression (e.g., shortened REM latencies), but also alterations in dream content. Nevertheless, there are some controversial results. The aim or our study was to clarify these inconsistencies by developing a design which might avoid some methodological problems which were present in some of these previous studies. Eleven male subjects slept in the laboratory for 7 consecutive nights. During 1 evenings they saw a stressful and a neutral movie in randomized order. The subsequent nights included REM sleep awakenings for the purpose of dream collections. Whereas the subjects were demonstrably affected by the disturbing films, the patterns of subsequent sleep remained unchanged. In contrast manifest content of the initial dreams were clearly altered. Whereas the modes of dreaming were quite different within post‐stress nights, mood was unproved the next morning in all subjects. The results are discussed within the framework of several prevailing concepts about sleep, dreams, and psychological strain.
Male Sexual Arousal as a Function of the Content and the Vividness of Erotic Fantasy
Authors: Smith David , Over Ray
Published: February 2007

Physiological and subjective arousal were measured across 5 sessions, each separated by a day or more, in which males attempted to induce erection through fantasy. Stable individual differences in the capacity to achieve voluntary enhancement of penile tumescence were found. The men who were most able to enhance erection were those who reported the greatest use of sexually arousing fantasy themes. In a second experiment, which employed structured rather than unstructured fantasy, sexual arousal was studied as a function of the content of fantasy and tbe vividness with which participants could form images (as assessed by Beits Q.M.I. Scale). Fantasy themes that had been independently rated as high in erotic value produced greater changes in penile circumference relative to baseline than themes of lower erotic value. Men with vivid imagery were more sexually aroused during fantasy than men with non‐vivid imagery. The interaction between the content and vividness of fantasy was not significant. These results indicate that the extent to which men can induce erection through fantasy depends not only on the sexual themes that the men use during fantasy, but on the vividness of the images they form.
Frontal Negative and Parietal Positive Components of the Slow Wave Dissociated
Authors: Loveless N.E. , Simpson M. , Näätänen R.
Published: February 2007

The so‐called ‘slow wave’ of tbe event‐related potential is composed of a slow frontal negative shift and a slow parietal positive shift which usually arc both present or both absent in records. A persistent question has been whether these slow shifts are generated by one and the same cerebral process or by two cerebral processes which tend to be evoked in very similar conditions, i.e., whether these two slow shifts can be dissociated. The present paper demonstrates such a dissociation. By recording these shifts to very infrequent auditory stimuli deviating in pitch from the frequent homogeneous stimuli of the sequence, a multitude of such data was obtained which permitted the identification and measurement of the slow frontal negative and the slow parietal positive shifts at the level of single trials. These data revealed no positive relationship between the amplitudes of the two shifts. Rather, the results showed an opposite tendency, i.e., a large frontal negativity was often associated with a small parietal positivity (or none) and vice versa.
Electrodermal Activity in Patients with Huntington's Disease and Their Progeny
Authors: Iacono William G. , Roshi Daniel , Lacoste Diane
Published: February 2007

Skin conductance was examined in patients with Huntington's disease (HD) and progeny at risk for HD to determine if electrodermal characteristics had potential to identify those progeny likely to succumb to HD. The two experimental groups chosen for study consisted of 7 patients in the early stages of HD and 29 progeny of HD patients. Because the HD and at‐risk groups differed in age and sexual composition, each was matched by age and sex to separate psychiatrically and medically healthy normal control samples. Skin conductance was recorded bilaterally while subjects listened to three series of stimuli: 8 85dB tones, 12 105dB tones, and two familiar sounds. Dependent measures included skin conductance level, number of nonspecific responses, number of responses elicited by each tone series and the sounds, the amplitude, latency, rise time, and half‐recovery rime of the first tone‐elicited response in each series, and habituation rate to the soft and loud tones. The data analysis was carried out by comparing each experimental group to its matched comparison sample. A variety of parametric and nonparametric tests were carried out; no significant differences emerged either between the HD patients and their control group or between the at‐risk subjects and their normal comparison group. Ninety‐seven percent and 86% of the at‐risk and HD subjects, respectively, responded at least once to the experimental stimuli, compared to 90% and 86% of the corresponding control groups.
Functional Differences Between Members of the P300 Complex: P3e and P3b
Authors: Ruchkin D.S. , Sutton S. , Mahaffey D.
Published: February 2007

The main findings of this study bear upon differences in the functional roles of P3b and a shorter latency, more centrally distributed endogenous positive component denoted as P3e. At the present writing, we have observed P3e only in conjunction with P3b. As in the case of P3b, P3e is fully endogenous in that it can be‐ elicited by omission of a stimulus if stimulus omission conveys relevant information to the subject. It was found that P3e and P3b relate differently to information delivery. Information delivery was manipulated by varying event probabilities and the discriminability of the events. The well known properties of P3b, namely that its amplitude is large when elicited by low probability (high information content) events and is reduced by perceptual difficulty (information loss‐equivocation), were replicated in the current study. In contrast to P3b, variation of event probability had no effect upon P3e amplitude, but increased perceptual difficulty markedly reduced P3e amplitude.

In addition, two CNV‐type negativities were observed in the epochs prior to presentation of the informative signal event: 1) A negativity that was maximal over central scalp related to the subject's prediction that a rare or frequent event would be presented; 2) A negativity that was maximal over occipital scalp related to a stimulus that informed the subject whether the subsequent discrimination of the signal would be easy or difficult. Finally, there was a serendipitous Hading of an apparently new short duration component, tentatively labeled Px, which is elicited by presentation of the signal that informs the subject whether the subsequent discrimination will be easy or difficult.
The Effect of Prestimulus Alpha Activity on the P300
Authors: Jasiukaitis Paul , Hakerem Gad
Published: February 2007

Trials on which highly discrepant, auditory ‘oddball’ stimuli were presented were sorted into two bins on the basis of prestimulus alpha band RMS magnitude. The trial bins were then separately averaged to produce a ‘high alpha’ auditory ERP (event‐related potential) and a ‘low alpha’ ERP for each subject. Study 1 found that larger amplitude P300s were obtained in the ‘high alpha’ ERP. No effect of alpha was found on the N100. Study 2 employed extra factors of stimulus intensity change (increases and decreases) and alpha measurement period (before and after the ‘oddball’ stimulus). It was found that P300 amplitude enhancement was independent of both stimulus intensity and the amount of alpha poststimulus. The data are discussed in terms of cascaded inhibition from the mesencephalic reticular formation to nucleus reticularis of the thalamus to a thalamo‐cortical system responsible for the generation of both alpha and the P300.