bluuebunny/crossref_metadata_2025 huggingface dataset:
Auditory Evoked Potentials to Unpredictable Shifts in Pitch
Authors: Ford Judith M. , Roth Walton T. , Kopell Bert S.
Published: February 2007

Auditory evoked potentials (EPs) were recorded from subjects presented with a regular series of tone pips at one of three rates (1/sec, 2/sec, or 4/sec). Occasionally one of the pips was 5%, 25%, or 100% (an octave) different in pitch from the repetitive background pips. These “mismatch” tones occurred at random with a mean interval of 12 sec (range 1–24 sec) for all of the repetition rates. This determined an average sequential probability = 0.083, 0.042, 0.021 that a tone would be a mismatch. On different runs, subjects either responded with a button press each time they heard a mismatch or they read a book. The amplitude of a large negative component (N2 at 154 msec) evoked after mismatch tones was unrelated to degree of mismatch but was larger to all the mismatch tones than to the background pip. Instructions to attend did not affect N2. A subsequent positive peak at 277 msec (P3), recorded during reading, did increase in amplitude with increasing mismatch, as did a P3 at 330 msec recorded during responding. Sequential probability had no main effect on N2 or P3. This lack of an effect on P3 suggests that the well‐known influence of stimulus uncertainty on P3 may be determined by the temporal rather than sequential uncertainty of events, or that our range of probabilities was too narrow to obtain the effect.
Hemispheric Laterality and Cognitive Style Associated With Transcendental Meditation
Authors: Bennett James E. , Trinder John
Published: February 2007

The hemispheres of the brain are thought to be specialized with respect to the manner in which they process information. In view of this it is possible to explore the way information is processed during the performance of a specified task by identifying the relative activity of the hemispheres. The hypothesis, that meditation is characterized by a gestalt, holistic and spacial cognitive style associated with the right hemisphere was tested. Sixteen Transcendental Meditators were compared to 16 control subjects with respect to the degree of lateral asymmetry during meditation‐relaxation and the performance of two analytic and two spacial cognitive tasks. Lateral asymmetry was assessed by the relative distribution of alpha activity. The only difference between the two groups was that meditators showed a greater degree of lateral asymmetry on both analytical and spacial tasks. During both meditation and relaxation the hemispheres were found to be symmetrical with respect to the distribution of alpha activity, suggesting that neither analytical nor spacial processing was dominant during these exercises.
Bilateral Electrodermal Activity, Lateralized Cerebral Processing and Sex
Authors: Ketterer Mark W. , Smith Barry D.
Published: February 2007

The present study involved the assessment of systematic differences between skin conductance measures recorded bilaterally and concomitantly from 59 right‐handed subjects while they were exposed to three types of stimuli. The stimuli were 5 min each of: a quiet period, a period of music, and a period of listening to a series of paragraphs. The music and paragraph conditions served, respectively, as operational definitions of right and left hemisphere tasks. Sex and genetic handedness were also assessed. Results showed that subjects with a family history of sinistrality gave more frequent SCRs on the left hand than on the right hand under the verbal condition, while those with entirely dextral families showed no left‐right differentiation. In addition, musical stimulation produced more frequent responses in males than females, while the reverse was true for verbal stimuli. Finally, tonic SCL was higher on the right hand in males and on the left in females. Stimulation intended for a specific hemisphere did not produce significantly greater electrodermal activity on the contralateral hand.
The Role of Instructions Versus Instructions Plus Feedback in Voluntary Heart Rate Slowing
Authors: Bouchard Marc‐André , Granger Luc
Published: February 2007

Two independent groups of human subjects (both sexes) received continuous binary feedback plus instructions or instructions alone in a heart rate (HR) slowing task. The results indicated that subjects in both groups decreased HR over time, but there were no salient group differences. This suggests that, at least for HR slowing, feedback is not a powerful controller of the behavior; indeed, the stronger statement that feedback is superfluous in HR slowing tasks seems warranted, but must be qualified since there was not a feedback‐only group. It was suggested that inclusion of a no‐feedback, instructions alone group, is a necessary condition from which to compare the effects of feedback.
Selective Lateralization of Cognitive Style Related to Occupation as Determined by EEG Alpha Asymmetry
Authors: Doktor Robert , Bloom David M.
Published: February 2007

This study reports a frequency analysis of hemispheric EEG asymmetries in 14 right‐handed male subjects performing two cognitive tasks. Eight of the subjects were Presidents or Chief Operating Officers of large corporations and the 6 remaining subjects were Operations Researchers. For the Operations Researchers, language and analytic tasks were expected to engage primarily the left hemisphere; spatial and intuitive tasks were expected to engage primarily the right hemisphere, consistent with earlier findings with normal subjects. The Presidents were expected to engage primarily the right hemisphere independent of cognitive task. Recordings from temporal leads (T3, T4) referred to the vertex CZ were subjected to discrete Fourier transforms; ratios of power from homologous leads (T4/T3) were computed in the alpha band. The results support the expectation of different responses between the two occupational groups. The lack of communication and understanding between the two occupational groups and the general lack of utilization and implementation of operations research by corporations may he inferred to be partially related to these differences.
The Effects of Presleep Stimuli of Different Sources and Types on REM Sleep
Authors: Cartwright Rosalind , Butters Elizabeth , Weinstein Martin , Kroeker Leonard
Published: February 2007

The sleep patterns of 12 experienced meditators and 9 age‐matched prospective meditators were compared to determine the effect of presleep stimuli of different sources and types on rapid eye movement (REM) sleep. All subjects were EEG monitored for two nights. On both nights the experienced meditators attended to internal stimuli, i.e. meditated prior to sleep, and the prospective meditators attended to external stimuli, i.e. listened to music through earphones, for an equal time. The music group had a significantly higher REM percent. Post hoc tests showed this was not due to a rebound following a difficult adaptation night. To test whether the elevation following music was a response specific to those committed to presleep external stimulus reduction, a second study compared the REM percent of a non‐meditation oriented student sample following presleep verbal or music stimulation to their base rate. These subjects showed REM percents higher than their base after music and lower than base following verbal stimulation.
Adrenalectomy‐Produced Facilitation of Pavlovian Conditioned Cardiodecelerations in Immobilized Rats
Authors: Wilson J. Roger , Simpson C. Wayne , DiCara Leo V. , Carroll Bernard J.
Published: February 2007

Previous evidence has suggested that both hormonal and behavioral aspects of adrenal stress activation may contribute to heart rate (HR) conditioning during physical/pharmacological immobilization. Accordingly, four studies were conducted to determine if bilateral adrenalectomy facilitates stimulus‐control over Pavlovian conditioned cardiodecelerations in rats immobilized either through physical restraint or neuromuscular paralysis. Plasma corticosterone assays were used as an index of the effectiveness of adrenal removal. The results showed that adrenalectomy facilitated both simple and discriminated Pavlovian conditioned cardiodecelerations in rats paralyzed with d‐tubocurarine chloride (dTC) without significantly altering the characteristics of EMG recovery from paralysis. Similarly, adrenalectomy facilitated simple Pavlovian HR conditioning in physically restrained rats. The results suggest that adrenal activation may disrupt the parasympathetically‐mediated Pavlovian conditioned cardiodeceleration in the physically‐and dTC‐immobilized rat. However, the specific nature of neuroendocrine mechanisms underlying cardiovascular conditioning during immobilization remains problematical.
Maternal Physiological Response to Infant Signals
Authors: Donovan Wilberta L. , Leavitt Lewis A. , Balling John D.
Published: February 2007

The present study reports the use of maternal physiologic responses as an index of maternal attention to infant signals. Thirty‐two women, each of whom had a 3‐month‐old infant, were shown 10‐sec silent images on a videotape monitor of a 3‐month‐old infant, en face, exhibiting either a smiling or a crying facial expression. Heart rate and skin conductance were recorded continuously while each woman viewed a sequence of 6 identical episodes of one expression followed by 6 episodes of the other expression. Both cardiac and skin conductance responses to the smile expression decreased following repeated presentations of the cry stimulus. Cardiac deceleration to the cry was prolonged following the viewing of the smiling infant. Mothers' perception of their own infants' temperament assessed by the Carey Infant Temperament Questionnaire (1970) was systematically related to maternal heart rate response. Mothers who described their infants as more difficult were physiologically less sensitive to changes in infant expressions. Results are discussed in terms of the impact of infant signals upon developing mother‐infant reciprocity.
Eyeblink EMG: A Miniature Eyelid Electrode for Recording from Orbicularis Oculi
Authors: Silverstein Louis D. , Graham Frances K.
Published: February 2007

Reflex blinking is primarily controlled by fast fibers of the palpebral portion of the orbicularis oculi but it is difficult to record EMG from these fibers with standard surface electrodes. To solve this problem, a small, easily‐prepared, silver/silver chloride electrode embedded in a dental cement casing was developed. Using this electrode, recordings could be obtained from the palpebral component which were of high quality and were many times larger than those recorded from the slow or mixed fibers in the orbital portion.
Electrolyte Medium Effects on Measurements of Palmar Skin Potential
Authors: Fowles Don C. , Schneider Robert E.
Published: February 2007

Two experiments with 12 subjects each compared skin potential recordings taken simultaneously with four different electrolytes. These were polyethylene glycol, hydrated agar (at a site presoaked with water), fresh agar (i.e., not presoaked), and Unibase. The glycol controlled epidermal hydration at a minimal level, while presoaking produced a high level of hydration at the hydrated agar site. Fresh agar and Unibase represented normal recording conditions for these two electrolytes which have been recommended as “standard” for electrodermal measurements. This design permitted a comparison of two standard electrolytes with each other and with recordings from hydrated and unhydrated sites. These comparisons were made for both monophasic negative SPRs and positive SPRs and the prestimulus levels associated with each.

The results replicated previous studies in showing a large effect of epidermal hydration on skin potential measurements. Recordings with agar and Unibase did not differ significantly. The effects of hydration were interpreted in terms of a reduction in the resistance of the stratum corneum and of alterations in the functioning of the dermal and epidermal membranes as a result of blockage of the sweat gland pore. In the light of this interpretation, it was suggested that both agar and Unibase substantially alter the functioning of the sweat glands under some conditions, and neither may be entirely suitable for skin potential measurements.
Effects of Electrodermal Lability and Payoff Instructions on Vigilance Performance
Authors: Sostek Andrew J.
Published: February 2007

The psychophysiologically based personality dimension of electrodermal lability has been related to vigilance performance. The present study investigated this effect basing lability on spontaneous electrodermal fluctuations and habituation of the electrodermal orienting response, and attempted to modify performance using monetary payoffs. In an auditory vigilance task, detections and sensitivity (d′) declined across blocks, and payoffs influenced detections, commission errors, d′, and response bias in the expected directions. Although there were no main effects for spontaneous lability, habituation labiles had higher log false alarm rates, lower response bias and tended to detect more signals. Using either lability criterion, labiles did not demonstrate a vigilance decrement and were more responsive than stabiles to payoff instructions. Lability based on habituation rate was therefore more clearly related to vigilance performance than lability based on spontaneous fluctuations.
Autonomic and Somatic Responses Associated With Performance of the Embedded Figures Test
Authors: McCanne Thomas R. , Hathaway Kate M.
Published: February 2007

Heart rate, skin potential, respiratory rate, and electromyographic activity from the biceps muscle were monitored while subjects performed the Embedded Figures Test. Increases in the phasic and tonic components of skin potential responding and in respiratory rate were noted during the presentation of embedded‐figure stimuli. A bidirectional change in heart rate consisting of an initial decrease followed by an increase was noted during the stimuli. In addition, differential changes in heart rate, skin potential phasic responding, and biceps muscle tension occurred preceding correctly solved and unsolved problems. Lowered heart rate and lowered rates of biceps electromyographic activity were detected during the presentation of the simple figure of solved problems relative to unsolved problems. Lower rates of skin potential phasic responding were noted during the simple figure of solved problems (relative to unsolved problems) for field dependent subjects. For field independent subjects, this differential pattern of skin potential phasic responding was reversed. The results are discussed in terms of the theoretical positions formulated by the Laceys and by Obrist.
Electro‐oculographic Recording and Scoring of Smooth Pursuit and Saccadic Eye Tracking: A Parametric Study Using Monozygotic Twins
Authors: Iacono William G. , Lykken David T.
Published: February 2007

Following reports that psychiatric patients and their relatives produced deviant oculomotion, new procedural and quantitative methods were developed and applied in a parametric study of tracking proficiency in 32 monozygotic twin pairs tested twice. Subjects tracked a spot of light across an oscilloscope screen. The target was driven sinusoidally at various frequencies for smooth pursuit tracking and by a modified square wave generator for saccadic tracking. Also included were a smooth pursuit test requiring subjects to “monitor” the aperiodic appearance of a hole in the center of the oscillating target and a psychomotor test requiring subjects to manually center a dot in a moving circle. For pursuit tracking, the electro‐oculogram (EOG) and target motion were fed to a computer programmed to calculate root‐mean‐square differences between EOG and target channels. The saccadic EOG was computer‐analyzed by measuring movement latencies.

Performance on the various tasks was analyzed with emphasis on the effects of the monitor requirement, which dramatically reduced tracking error. Measures of retest reliability and twin concordance suggested that observed individual differences in performance on these tasks represent stable traits.
Cardiac‐Respiratory‐Somatic Relationships and Feedback Effects in a Multiple Session Heart Rate Control Experiment
Authors: Levenson Robert W.
Published: February 2007

An experiment addressing several unresolved issues in operant conditioning of heart rate (HR) in human subjects was performed. Cardiac‐respiratory relationships, cardiac‐somatic relationships, effects of biofeedback, and individual differences were examined in terms of their stability across multiple training sessions.

Thirty subjects participated in 3 training sessions. Each session began with 4 trials of attempted HR change without feedback followed by 8 trials with “proportional” feedback of HR. On half the trials HR decrease was attempted while HR increase was attempted on the other half. Subjects were instructed to keep their respiration rate (RR) constant and not to engage in undue movement or muscle activity.

Results indicated that subjects were able to produce significant HR increases and decreases from baseline levels, but these changes were accompanied by parallel changes in respiratory and somatic variables which persisted across sessions. Analysis of data from individual subjects was performed to explore the nature of individual differences in cardiac‐respiratory‐somatic patterns. The effects of biofeedback were unimpressive, suggesting at best a minor improvement in cardiac control with increased respiratory concomitance. Cardiac control, feedback effects, and cardiac‐somatic patterns were stable over sessions. There was evidence of some reduction in cardiac‐respiratory parallelism across sessions.
Attention and Vigilance: Performance and Skin Conductance Response Changes
Authors: Blakeslee Pat
Published: February 2007

The skin conductance response component of the orienting reflex was used to measure changes in attention during vigilance performance in order to test several hypotheses which have related aspects of vigilance performance to the occurrence and habituation of orienting or observing responses. Subjects detected irregularly presented visual signals among similar visual events during two 30‐min tasks. Skin conductance responses were analyzed in epochs of time immediately preceding and following signals and in nonsignal‐related time epochs. Magnitudes of skin conductance responses declined in both signal‐related epochs (pre and post), but this decrement was correlated with performance changes only in the post‐signal epoch. There was no decrement in SCR magnitudes during the nonsignal‐related epochs. Skin conductance response magnitudes were significantly larger both before and after detected signals compared to misses. The data support the hypothesis that changes in vigilance performance over time are related to habituation of the orienting reflex evoked by signals. They also suggest that attentional processes preceding signals are related to successful detections.
Sex Differences in Task‐Dependent EEG Asymmetries
Authors: Trotman Sandra C. A. , Hammond Geoffrey R.
Published: February 2007

Different patterns of lateralization of hemispheric function in the male and female brain have been proposed to account for sex differences in performance of linguistic and visuo‐spatial tasks. The present experiment was designed to determine whether task‐related asymmetries in suppression of the alpha rhythm differed between the sexes. Bilateral EEGs were recorded from 5 male and 5 female subjects while they performed 3 verbal‐numeric and 3 visuo‐spatial tasks. The proportion of right hemisphere alpha activity differed between these tasks for the male group but not for the female group. This result suggests a sex‐related difference in degree of lateralization of hemispheric function, with males having a more strict segregation of function.
P300 and Tracking Difficulty: Evidence For Multiple Resources in Dual‐Task Performance
Authors: Isreal Jack B. , Chesney Gregory L. , Wickens Christopher D. , Donchin Emanuel
Published: February 2007

Subjects performed a visual tracking task while performing a concurrent task in which tones were covertly counted. The P300 component of the event‐related potentials elicited by the tones was examined to determine the extent to which its amplitude was affected by variations in the forcing‐function bandwidth, or difficulty, of the tracking task. P300 decreased in magnitude when tones were counted in conjunction with the performance of the tracking task, relative to a single‐task counting condition. Increasing tracking difficulty failed to reduce P300 amplitude further. A second experiment obviated the possibility that movement‐related potentials caused the P300 attenuation resulting from the introduction of the tracking task. In Experiment 3, subjects performed a reaction time task in conjunction with tracking in order to establish the validity of the tracking difficulty manipulation. The results are interpreted in terms of a theory of functionally‐specific processing resources.
Sleep Following Sustained Exercise
Authors: Browman Carl P.
Published: February 2007

This study was designed to assess the effect of individually calibrated sustained, static exercise on sleep. Normal subjects engaged in 80 min of static muscular activity at 40% of maximal levels. The exercise ended 2 hrs before bedtime. Standard polysomnographic measures were recorded during sleep. The time to sleep onset was significantly reduced relative to nonexercise nights. Other significant comparisons (increased slow‐wave sleep and decreased movement time after exercise) were confined to the period preceding the first REM episode. The results indicated that the type of exercise may be related to the effect on sleep latency. The data supported a restorative theory of slow‐wave sleep.
Energy Expenditure, Heart Rate, and Ambulation During Shock‐Avoidance Conditioning of Heart Rate Increases and Ambulation in Freely‐Moving Rats
Authors: Brener Jasper , Phillips Keith , Connally Samuel
Published: February 2007

Using shock‐avoidance procedures with equivalent reinforcement criteria and in a running wheel situation, one group of rats was reinforced for heart rate increases (HR group) and another group for running (Amb group). Throughout 5 Habituation sessions and 5 Conditioning sessions, each 2 hrs in duration, continuous recordings were made of heart rate (HR), ambulation (Amb), and oxygen consumption (OC). The groups did not differ in their mean levels of HR, Amb or OC during Habituation or during Conditioning, although the introduction of the contingencies did elicit significant increases in the mean levels of all three variables. Amb group subjects distributed their activity more effectively in relation to the experimental contingencies, resulting in 5/6 subjects acquiring successful avoidance behavior against only 2/5 subjects in the HR group. Examination of individual subjects in both groups indicated that learners all exhibited very similar behavior profiles regardless of the contingencies applied during conditioning, and the same was true of nonlearners. Accordingly the data were regrouped for learners and nonlearners and reanalyzed. These analyses revealed that nonlearners differed from learners in the nature of the relationships they displayed between variations in HR, OC and Amb during both the preconditioning (habituation) and conditioning phases of the experiment. These differences are discussed together with data derived from additional conditioning sessions in which autonomic blocking agents (Propranolol and Methyl Atropine) were administered to a subgroup of learners.
Generalized Muscle Changes during EMG Relaxation Training
Authors: O'Connell Michael F. , Yeaton Susan P.
Published: February 2007

Tension levels from muscles in the forehead (frontalis) and back of the neck (semispinalis capitis) were simultaneously recorded during short term relaxation training with EMG feedback to assess the efficacy of this technique for producing generalized deep muscle relaxation. The degree of association between the activity of the two muscles was measured both with cross‐correlation coefficients and a linear regression technique. The two muscles showed a tendency to covary which did not change during training and was unrelated to which muscle was the source of feedback. These results provide evidence for a moderate degree of association between these muscle groups during relaxation training and suggest that EMG feedback may be more useful in producing general relaxation than was previously thought.
Pulse Transit Time as an Indicator of Arterial Blood Pressure
Authors: Geddes L. A. , Voelz M. H. , Babbs C. F. , Bourland J. D. , Tacker W. A.
Published: February 2007

The relationship between pulse‐arrival times and diastolic blood pressure was measured in 10 anesthetized dogs. The pulse‐arrival time was measured using the R‐wave of the electrocardiogram (ECG) as a time reference. Pulse‐transit time was also measured between the carotid and femoral pulses. Blood pressure was raised with epinephrine injected intravenously and lowered with vagal stimulation. In all cases, pulse arrival and transit times decreased with an increase in diastolic pressure for diastolic pressures ranging from 15 to 250 mmHg. The correlation between pulse‐arrival time and pressure was poorest when the ECG was used as a timing reference. The best correlation was found with true pulse‐transit time and diastolic pressure. When pulse‐transit time was used to compute pulse‐wave velocity, it was found to increase nearly linearly with blood pressure. From 90–100 mmHg, the pulse‐wave velocity increased typically by slightly less than six percent.
Effects of Instructions and Contingency of Reinforcement on the Operant Conditioning of Human Phasic Heart Rate Change
Authors: Riley Diane M. , Furedy John J.
Published: February 2007

The aim of these studies was to determine the effects of instructions and reinforcement contingency on phasic heart rate (HR) change. In Exp. I, 36 human subjects were given 20 conditioning trials with a muscletensing task which produced a phasic HR acceleration. The experimental manipulation produced an elevated baseline and allowed for the observation of instructed HR change during exercise. A 2 × 2 between subject design varied instructions (to increase or decrease the phasic tension‐induced HR acceleration) and contingency (whether the verbal reinforcement was contingent on or unrelated to HR change) as factors. There was a significant instructional effect at the end of conditioning, with increase subjects producing more HR acceleration and decrease subjects less acceleration relative to pretrials. The instructional effect developed over trials and decrease subjects significantly improved with practice. There was no difference between contingent and non‐contingent groups in either of the two conditions in ability to change HR in the instructed direction. This study shows the usefulness of the elevated baseline technique for cardiac research. A second experiment demonstrated that, in subjects not instructed to attempt HR change, the phasic HR response did not change in magnitude over conditioning. The results of these studies indicate that subjects are able to control phasic HR during physical‐stress induced tension but biofeedback is not relevant for the production of such HR changes.
Adjustment of Circadian Rhythms and EEG Sleep Functions to Day and Night Sleep Among Permanent Nightworkers and Rotating Shiftworkers
Authors: Dahlgren Kerstin
Published: February 2007

Six workers on a permanent night work schedule and 6 workers on a weekly rotating day‐night shift schedule were compared with regard to the quantity and quality of sleep as measured by EEG recordings, sleep diaries, and subjective ratings of sleep. They were also compared regarding the degree of adjustment of the body temperature rhythm and self‐rated activation. The observations for all variables were made at the beginning, end, and after the end of the night shift period, and also in connection with free days. It was shown that compared to rotating shiftworkers the permanent nightworkers exhibited a better adjustment of the body temperature rhythm to night work and day sleep and also had fewer disturbances in sleep functions during day sleep. The rotating shiftworkers showed the poorest adjustment of the body temperature rhythm and sleep functions during day sleep at the beginning of the night shift week, whereas for permanent nightworkers corresponding, albeit less pronounced, disturbances were present in connection with night sleep. It was concluded that there was a close relationship between the degree of adjustment of the body temperature rhythm and EEG sleep functions, with a permanent night work schedule facilitating the adjustment to night work.
The Psychological Significance of Task‐Induced Tonic Changes in Somatic and Autonomic Activity
Authors: Svebak Sven , Dalen Knut , Storfjell Olger
Published: February 2007

Two experiments tested the view that task‐induced autonomic‐somatic gradient parallelism does exist and that the steeper the physiological gradients, over the course of a task, the more involved the subject and the greater the effort. Thirty‐three male subjects performed easy and difficult versions of a continuous reaction time task. In both experiments the difficult task prompted steeper electromyographic (EMG) activity gradients than did the easy version. Scores on heart rate (HR) and skin conductance did not show clear gradients. However, task‐dependent effort was positively related to the magnitude of the initial HR acceleration and to the steepness of the EMG gradient. The autonomic‐somatic coupling hypothesis of Obrist did not explain the results. Instead, evidence for ventilatory‐somatic parallelism was found.
The Effects of Serial Order in Long Sequences of Auditory Stimuli on Event‐Related Potentials
Authors: Hermanutz Max , Cohen Rudolf , Sommer Werner
Published: February 2007

The generalizability of the model relating P300 amplitudes to subjective probabilities, developed by Squires et al. (1976) for random series of events, was examined with respect to long sequences of repetitions, which had been restricted in randomness, allowing only for sequences of between 4 and 12 frequent clicks. Subjects were asked to silently count either the rarer of two clicks, presented with a probability of .10, or light stimuli occurring with the same temporal distribution.

Within these limits there was an increase in P300 amplitude not only to the rare clicks, but also—contrary to predictions from the model—to the frequent non‐target clicks following longer series of repetitions, provided that clicks had to be counted. A plausible interpretation might be that the longer the series of repetitions in long non‐random sequences with low predictability, the more the subjects become involved in the “stimulus evaluation” of both kinds of events. A similar increase across serial position was found for the N100 component to frequent clicks when the auditory modality was defined as task relevant, and was interpreted as progressive focusing of selective attention. For the rare clicks there occurred a decrease in a slow Negative Shift with peak amplitude at 220 msec after long series of non‐targets, possibly reflecting a facilitative effect of the focused attention on decision processes related to target detection. There were no differences between normals and chronic alcoholics with respect to the above‐mentioned effects.
Event‐Related Brain Potentials in a Stimulus‐Discrimination Learning Paradigm
Authors: Rösler Frank
Published: February 2007

Event‐related brain potentials were recorded from human subjects performing a stimulus‐discrimination learning task. Brain activity was averaged separately for different stimulus attributes, either relevant or irrelevant for the discrimination, and for different stages of learning. Learning‐specific amplitude changes occurred in two positive peaks of the ERP (P160 and P330): a) the amplitudes of both components decreased continuously over blocks; b) with increasing practice the amplitudes to irrelevant attributes became significantly smaller than those to relevant attributes; and c) the point at which the amplitudes to relevant and irrelevant attributes diverged was earlier for P330 and later for P160. The different trends of the amplitudes of the two peaks suggest that they reflect functionally distinct processes of attentional set. Peak latencies and other amplitude measures of the ERP (baseline shift, N100, slow wave) showed no learning‐specific, but systematic long‐ and short‐term habituation/facilitation effects.
Electrodermal Responses to Auditory Stimuli with Different Significance in Neurological Patients
Authors: Schuri U. , von Cramon D.
Published: February 2007

In 16 neurological patients with different levels of severely disturbed vigilance and 16 healthy subjects electrodermal responses to the name and the name backwards were elicited. In the most severely impaired patients, no differences were found between stimulus conditions. In less severe cases, significantly larger responses to the name were found but only on initial trials. In normal subjects differences persisted throughout 10 presentations of each stimulus. All subject groups demonstrated habituation.
The Effects of Pharmacological Manipulations that Influence Vagal Control of the Heart on Heart Period, Heart‐Period Variability and Respiration in Rats
Authors: Yongue Brandon G. , McCabe Philip M. , Porges Stephen W. , Rivera Margaret , Kelley Susan L. , Ackles Patrick K.
Published: February 2007

Changes in heart period (HP), heart‐period variance (HPV), and the respiratory component of HPV in freely moving rats were examined following pharmacological manipulations known to influence vagal control of the heart. Spectral analysis was used to quantify the component of HPV associated with respiration which is proposed to be sensitive to vagal influences on the heart. The respiratory component of HPV is described by a statistic, V̌, which is the sum of the spectral densities of the heart period spectrum across the band of frequencies associated with normal respiration. Vagal tone was reflexively enhanced by phenylephrine or peripherally blocked by atropine.

Phenylephrine produced biphasic changes in HP and V̌, with the increases lasting from 0.5 to 2 hrs. Atropine resulted in significant decreases in HP, HPV and V̌. These decreases were immediate and sustained throughout the experiment, although there were signiflcant linear increases in HP and HPV from their initial post‐injection values. In the saline condition, HP increased linearly across time.

Results were discussed in terms of vagal and non‐vagal control of the heart. It was suggested that, while all three variables are altered by manipulations of vagal influences on the heart, V̌ seems to be influenced less by non‐vagal control than HP and HPV.
Electrodermal Recovery and Stimulus Significance
Authors: Janes Cynthia L.
Published: February 2007

The validity of Edelberg's (1970) hypothesis that speed at which the electrodermal response (EDR) recovers is affected by meaning of the stimulus evoking it, has been challenged by subsequent work showing prior ED activity's (EDA) highly significant association with ED recovery time. However, prior EDA's association with ED recovery does not rule out the possibility that the stimulus meaning may also affect recovery. In the present study a within‐subjects design (N = 10) was used to evaluate effects of stimulus significance on skin conductance response (SCR) amplitude and recovery time (rec t/2) while prior EDA was held constant. Amplitude was greater and rec t/2 longer (slower) when the stimulus significance increased, and the effect on recovery did not depend entirely on amplitude. Prior EDA also affected amplitude and recovery but stimulus meaning had an additional effect. These findings contradict the notion of the EDR as a unitary phenomenon, and imply that both peripheral and central mechanisms are involved in determining response amplitude and recovery. Stimulus meaning may affect recovery to an even greater degree than it affects amplitude.
Event‐Related Potentials to a Change of Pace in a Visual Sequence
Authors: Ford Judith M. , Pfefferbaum Adolf , Kopell Bert S.
Published: February 2007

Visual event‐related potentials (ERPs) were recorded from 11 subjects presented with a sequence of brief flashes occurring at a regular interstimulus interval (ISI) of 1200 msec. Occasionally and unpredictably a flash occurred early ‐ 450, 375, or 300 msec after the previous flash. On one run, subjects responded with a button press to the early flashes; on the other, they listened to a story presented over headphones and the flashes were not task relevant. Two distinct negativities (N1 and N 2) were elicited, and each was affected by a combination of task and stimulus variables. The amplitude of N1 (143 msec), appearing at the vertex and occiput, was affected by event probability as well as the ISI and task relevance of the early flashes. The N2 (230 msec) to the visual pace change was dependent on attention and was relatively unaffected by further shortening of ISI. The P3 was larger to the early than regular flashes and was greatly affected by the task relevance of the early flashes.
The Effects of Slow Cortical Potentials on Response Speed
Authors: Rockstroh Brigitte , Elbert Thomas , Lutzenberger Werner , Birbaumer Niels
Published: February 2007

The relationship between slow cortical potentials (SCPs) and response speed was investigated by training subjects to induce different cortical shifts by means of a biofeedback procedure. During two identical experimental sessions trials with visual feedback of the actual DC‐shifts alternated with reaction time trials without feedback. In reaction time trials only the signal for the required change in polarity was provided. At the end of the signal interval an immediate button‐press was required to stop a hissing noise. Two groups of 10 subjects each were investigated, one group receiving feed back from the left precentral recording(C3) and the other from the right precentral recording (C4). Results showed that subjects achieved control over their SCPs. At the end of the training period in the second session significant differences in SCPs between trials of the different required polarities were observed, during feedback trials as well as during reaction time trials without feedback. Subjects responded faster during trials in which a change toward more cortical negativity was required as compared to trials requiring less negativity.
Isolated REM Sleep Facilitates Recall of Complex Associative Information
Authors: Scrima Lawrence
Published: February 2007

This study directly tested the beneficial effect of isolated REM and isolated NREM sleep on the recall of narcoleptics. In a within subject design, 10 narcoleptics were instructed to sleep for a certain optimal duration and at a certain optimal time before each session, and were given 12–14 sessions, one a day, on different lists of a complex associative memory task and a minimally associative memory task. Following the 10‐min task, the subject either had 20 min of polygraphically recorded napping or card playing, followed by a free recall test. The results for the complex associative task indicated significant differences between the three conditions for free recall. Recall was significantly better after isolated REM than after isolated NREM sleep or wakefulness and was significantly better after NREM than after wakefulness. The results from the minimally associative task were inconclusive. The results are consistent with the proposed neuronal activity correlates (NAC) theory that REM sleep actively consolidates and/or integrates complex associative information and that NREM sleep passively prevents retroactive interference of recently acquired complex associative information.
Visual Evoked Potentials Change as Heart Rate and Carotid Pressure Change
Authors: Walker Barbara B. , Sandman Curt A.
Published: February 2007

The relationship between cardiovascular activity and the brain was explored by recording visual evoked potentials from the occipital regions of the scalp during systolic and diastolic pressure (Experiment I) and during fast and slow heartbeats at systolic and diastolic pressure (Experiment II). Visual evoked potentials changed significantly as heart rate and carotid pressure fluctuated normally, and these changes were markedly different in the right and left cerebral hemispheres. Evoked potentials recorded from the right hemisphere during various cardiac events differed significantly, whereas those recorded from the left did not. In both experiments, differences in the right hemisphere were due primarily to the P1 component, which was larger at diastolic than at systolic pressure. The present findings are consistent with formulations from behavioral studies suggesting that baroreceptor activity can influence sensory intake, and suggest that hemispheric specialization may play an important role in the relationship between cardiac events, the brain and behavior.
The Influence of Uncertainty and Visual Complexity on Habituation of Electrodermal and Visual Orienting Reactions
Authors: Verbaten M. N. , Woestenburg J. C. , Sjouw W. , Slangen J. L.
Published: February 2007

This experiment investigated the effects of stimulus complexity and stimulus uncertainty on habituation of the visual orienting reaction (VOR) and the skin conductance orienting reaction (SCR) in four groups of 14 subjects each. Half the subjects were told that the same stimulus would be presented a number of times in the right upper comer of the TV screen (“certain condition”), and the other half were not informed about the stimuli (“uncertain condition”). Within each of these groups, half the subjects received 14 stimuli of 12 bits information and the other half received 14 stimuli of 60 bits information. Stimulus complexity and stimulus uncertainty led to both slower habituation of the VOR and stronger VORs on trial 1. Neither factor, howev, had a significant effect on SCR magnitude or habituation. It was concluded that the VOR and SCR represent different aspects of stimulus processing. The results of this experiment were discussed in terms of the roles which VORs and SCRs may play in selective attention.
The Elicitation and Habituation of Orienting and Defensive Responses to Phobic Imagery and the Incremental Stimulus Intensity Effect
Authors: Grayson Jonathan B.
Published: February 2007

Using imaginal stimuli, the present investigation examined psychophysiological responses to imagery and the roles of Groves and Thompson's (1970) dual process theory and Sokolov's (1963) model of the defensive response(DR) in mediating the incremental stimulus intensity effect (ISIE). Experiment I was undertaken to determine whether phobic and neutral imagery could be discriminated by DRs and orienting responses (ORs). In a within groups design. 19 analogue speech phobics were exposed to 4 neutral and 4 phobic scenes. Dependent measures were skin conductance measures and second‐by‐second heart rate (HR). The results showed that DRs occurred only in response to phobic scenes. In a between groups design. Experiment II compared an incremental series (IS) of 16 phobic imaginal stimulus presentations to a constant series. Subjects were analogue speech phobics with 14 subjects per condition. For both conditions the last 4 scene presentations were the same. Dependent measures were second‐by‐second HR, second‐by‐second cephalic pulse amplitude, and skin conductance measures. The results showed greater habituation in the IS condition, but were inconclusive with regard to the roles played by dual process theory and the DR model in the ISIE.
Sleep Loss and Nap Effects on Sustained Continuous Performance
Authors: Mullaney Daniel J. , Kripke Daniel F. , Fleck Paul A. , Johnson Laverne C.
Published: February 2007

Thirty young male volunteers participated in a study of sustained continuous performance using a variety of computer‐based tasks. After 6 hrs of recorded sleep, 10 subjects were assigned to perform continuously for 42 hrs without break. Three of these subjects were unable to complete the 42‐hr assignment, and 8 of the 10 suffered psychological events such as hallucinations and disorientation. Ten subjects permitted six 1‐hr naps over the 42 hrs performed more successfully than those allowed no sleep. Ten subjects permitted one 6‐hr rest period performed best of all. Fatigue effects appeared after 6 hrs. Time‐of‐day (circadian) effects were at times stronger than fatigue.
Motor Preparation: Changes in Amplitude of Achilles Tendon Reflexes During a Fixed Foreperiod of One Second
Authors: Brunia C.H.M.
Published: February 2007

Achilles tendon (T) reflexes were evoked simultaneously in both legs during a fixed foreperiod of 1 sec. Volunteers were instructed to react as quickly as possible by one of four responses (in blocks): a plantar flexion of the left or right foot and a flexion of the left or right index finger. Prior to a foot response one leg was always involved in the response, prior to a finger response neither leg. Reflexes were evoked at 13 different points in time, from 100 msec prior to the warning signal (WS) to 100 msec after the response signal (RS). Amplitudes were expressed in percentages of control (intertrial interval) reflex amplitudes. In all conditions, amplitudes in both legs reached a peak 100 msec after the WS. After this non‐selective increment, reflex amplitudes preceding a finger response decreased but remained larger than the baseline. Prior to a foot movement, amplitudes in uninvolved muscles remained larger than the baseline as well, whereas amplitudes in the involved muscle were no longer different from the baseline. This differential effect was independent of the response side. It was concluded that preparation for a response is characterized by a selective lack of activation in the reflex arc of the agonist, and a non‐selective activation of the uninvolved spinal motor structures.
On the Utility of T‐Wave Amplitude: A Reply to Schwartz and Weiss
Authors: Heslegrave Ronald J. , Furedy John J.
Published: February 2007

Although Schwartz and Weiss's (1983) paper purports to be a response to Furedy and Heslegrave (1983), it does not address the central thesis of that the paper: that the recent criticisms of the T‐wave amplitude (TWA) index of sympathetic activity were invalid. Instead, Schwartz and Weiss (1983) prefer to raise further criticisms concerning the validity of the TWA index. In this reply, we provide some clarifications and evaluations of these further points. Our conclusion remains that these further criticisms are insufficient to support abandoning TWA, and that rather the available evidence supports continuing the critical appraisal of TWA along with other candidate sympathetic indices.
Pattern Recognition of Self‐Reported Emotional State from Multiple‐Site Facial EMG Activity During Affective Imagery
Authors: Fridlund Alan J. , Schwartz Gary E. , Fowler Stephen C.
Published: February 2007

A multivariate pattern‐classification system was developed for the study of facial electromy‐ographic (EMG) patterning in 12 female subjects during affect‐laden imagery and for posed facial expressions. A parameter‐extraction procedure identified the dynamic EMG signal properties which accorded the maximal degree of self‐reported emotion discrimination. Discriminant analyses on trialwise EMG vectors allowed assessment of specific EMG‐site conformations typifying rated emotions of happiness, sadness, anger, and fear. The discriminability among emotion‐specific EMG conformations was correlated with subjective ratings of affective‐imagery vividness and duration. Evidence was obtained suggesting that the EMG patterns encoded complex, “blended” reported affective states during the imagery. Classification analyses produced point‐predictions of reported emotional states in 10 of the 12 subjects, and provided the first computer pattern recognition of self‐reported emotion from psychophysiological responses.