bluuebunny/crossref_metadata_2025_split huggingface dataset:
Event‐Related Potentials to a Change of Pace in a Visual Sequence
Authors: Ford Judith M. , Pfefferbaum Adolf , Kopell Bert S. 
Published: February 2007

ABSTRACTVisual 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

ABSTRACTThe 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

ABSTRACTThis 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

ABSTRACTThe 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

ABSTRACTThis 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

ABSTRACTUsing 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

ABSTRACTThirty 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

ABSTRACTAchilles 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

ABSTRACTAlthough 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

ABSTRACTA 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.
Voluntary Movement and Excitability of Cutaneous Eyeblink Reflexes
Authors: Sanes Jerome N. 
Published: February 2007

ABSTRACTReflex responses from eyelid muscles were evaluated when subjects prepared to or made brief or sustained voluntary contractions of eyelid or forearm muscles in a signaled reaction time task. The eyeblink reflex consists of an early and unilateral response, R1, and a longer latency bilateral response, R2. A similar pattern of reflex excitability was observed for all phasic movements. The R1 was transiently potentiated by the warning stimulus, increased again at the end of the preparatory period, increased more in the reaction interval and immediately after movement onset, and finally declined to control levels by 500 ms after onset of voluntary movement. The R2 responses were typically depressed at the same times that R1 responses were enhanced. When sustained contractions were performed and reflexes were elicited after movement eyelid onset, the patterns of early R1 enhancement and R2 depression occurred, both for about 500 ms, and gave way to continued R1 and also R2 enhancement as long as eyelid movement continued. The different behavioral responses of R1 and R2 reflect differences in the physiological properties of the separable neuroanatomical pathways for the two eyelid reflex responses.
Amplitude and Bandwidth of the Frontalis Surface EMG: Effects of Electrode Parameters
Authors: van Boxtel A. , Goudswaard P. , Schomaker L.R.B. 
Published: February 2007

ABSTRACTIn the present investigation, the frontalis surface EMG was differentially recorded during static voluntary submaximal contractions. First, mean rectified EMG (MREMG) and EMG signal bandwidth were examined for two different bilateral EMG derivations (superior and inferior) with the electrodes placed in horizontal direction and two unilateral derivations (left and right) with the electrodes placed in vertical direction. MREMG was significantly different between the four derivations but absolute differences were small. Bandwidth also varied significantly with derivation. Second, the influence of inter‐electrode distance and electrode size was examined for unilateral derivations. The influence of inter‐electrode distance on MREMG was significant but the absolute effect was marginal. We suggest that a clear effect is to be expected only within the range of small distances (smaller than 10 mm). The significant effect disappeared when MREMG was expressed as proportion of the MREMG during maximal contraction. This normalization seems to allow better intra‐individual or inter‐individual comparisons of integrated EMG, especially when different recording methods are used. The influence of inter‐electrode distance on bandwidth was not significant. Electrode size had no significant influence on MREMG and bandwidth. EMG power spectra indicated that integrated frontalis EMG can be validly measured only when using recording equipment with a frequency response of 5–500 Hz.
Cardiovascular Effects of Mental Arithmetic in Type A and Type B Females
Authors: Lane James D. , White Alice D. , Williams Redford B. 
Published: February 2007

ABSTRACTThe cardiovascular responsivity of women demonstrating the Type A coronary‐prone behavior pattern was investigated by presenting female Type A and Type B subjects with a challenging mental arithmetic task. Female subjects responded to the task with elevations in heart rate, blood pressure, and forearm blood flow, but did not show the active vasodilatation in the forearm vasculature seen in males in an earlier study. Type A females as a group were not hyperresponsive compared to Type B. However, measures of Type A behavior interacted with family history of hypertension such that, in the subgroup with a positive family history, the Type A behavior pattern was associated with larger cardiovascular responses. The results suggest that sex differences could be present in the expression of the cardiovascular concomitants of Type A behavior. Both gender and family history of cardiovascular disease may represent additional dimensions in the understanding of the pathological mechanisms linking Type A behavior and coronary disease.
Peak Alpha Frequency of EEG during a Mental Task: Task Difficulty and Hemispheric Differences
Authors: Osaka Mariko 
Published: February 2007

ABSTRACTTo investigate the effect of task difficulty on the alpha wave, bilateral EEGs were recorded from frontal and occipital locations from 5 male and 5 female students while they were engaged in two arithmetic (simple addition, SA, and complex addition, CA) and two visuo‐spatial (visual imagery, VI, and mental rotation, MR) tasks. During both the arithmetic and the visuo‐spatial tasks, peak alpha frequency of power spectrum increased significantly above the resting level. Moreover, the frequency shift was significantly larger in the CA and MR conditions than in the SA and VI conditions. The shift increased as the task difficulty increased. A hemispheric effect was found: the peak alpha frequency increased in the left rather than in the right during the arithmetic tasks whereas it increased in the right rather than in the left during the visuo‐spatial tasks.
Effects of Cigarette Smoking on Bilateral Skin Conductance
Authors: Boyd Gayle M. , Maltzman Irving 
Published: February 2007

ABSTRACTBilateral skin conductance was recorded from 8 male and 8 female cigarette smokers and from 8 male and 8 female nonsmoker control subjects on two different days. On one day smokers smoked a cigarette prior to the recording session and on the other they remained abstinent. Subjects also engaged in tasks designed to differentially involve the cerebral hemispheres. SCR asymmetry was measured using two different indices. During both the resting and task periods smokers had larger SCRs in their right than left hands following smoking. Unlike control subjects during the first recording session, smokers did not show task related changes in SCR asymmetry. During tasks smokers showed smaller SCRs in both hands following smoking than following abstinence. Changes in SCR asymmetry associated with smoking were seen in subjects who smoked more cigarettes, reported more subjective craving, were more introverted, and indicated a preference for cognitive processes and strategies associated with the left hemisphere. Results are discussed in terms of relative involvement of the cerebral hemispheres following smoking and smoking abstinence.
Forty Hertz EEG Activity in Dementia of the Alzheimer Type and Multi‐Infarct Dementia
Authors: Loring David W. , Sheer Daniel E. , Largen John W. 
Published: February 2007

ABSTRACTHigh frequency EEG activity within the 40 Hz band was examined at rest and during two problem solving tasks in patients with presumptive diagnoses of either dementia of the Alzheimer type (DAT) or Multi‐Infarct Dementia (MID), and in normal elderly subjects. The DAT patients differed significantly from normals and MID subjects, exhibiting both decreased rates of 40 Hz EEG activity and no task‐appropriate pattern of cerebral lateralization. Although MID patients did not differ from controls during baseline, significantly less 40 Hz activity was present during performance of a sentence repetition task. Evidence for normal task‐specific asymmetry was present in the MID and control groups. The results suggest that patterns of 40 Hz EEG activity may be of utility in the early diagnosis of DAT. Further, the 40 Hz rhythm appears able to discriminate between patient populations that present with similar patterns of dementia.
Second Thoughts: Multiple P300s Elicited by a Single Stimulus
Authors: Johnson Ray , Donchin Emanuel 
Published: February 2007

ABSTRACTIn a previous report (Johnson & Donchin, 1978), we manipulated the discriminability of tone pairs that delivered feedback information in a time‐estimation paradigm. As in other experiments using feedback stimuli, the event‐related potentials elicited by these stimuli did not return to baseline in the 800‐ms poststimulus interval. Since we were interested in this “Slow Wave'’activity, the poststimulus interval was lengthened to 1500 ms. Averages revealed that a second positive peak was present for some of the individual subjects. To investigate this activity further, the filtered singletrial waveforms were inspected visually. These data were characterized by the presence of one, and occasionally two, positive peaks, with highly variable latencies, following the P300. These peaks were indistinguishable in frequency and general appearance from the P300s elicited by the feedback stimuli. After latency adjusting the waveforms on the peak of the second positive wave, amplitude and latency were quantified. Whereas P300 amplitude was directly related to stimulus discriminability and positive feedback elicited larger P300s than negative feedback, the amplitude of the second positive wave was constant across levels of discriminability and the same for both types of feedback. In contrast, the latencies of both waves were inversely related to stimulus discriminability and shorter following positive feedback than negative feedback. Evidence is presented to support our contention that these additional positive peaks represent P300 activity. The data are discussed in terms of what these multiple P300s reveal about human information processing.
Effects of UCS Probability on the Contingent Negative Variation and Electrodermal Response During Long ISI Conditioning
Authors: Backs Richard W. , Grings William W. 
Published: February 2007

ABSTRACTNine subjects participated in a long ISI, trace conditioning paradigm. Tone CSs, at three different frequencies, signaled that a loud noise UCS would occur with either a .17, .50, or .83 probability. Subjects were instructed on the CS‐UCS contingencies. To avoid effects of differential motor preparation, two button presses were required on each trial. Button presses were signaled by lights, one second after the point at which the UCS would occur. EDR was recorded from the nonpreferred hand; EEG was recorded from the Cz and Pz sites. Only responses to the CSs were quantified. For the EDR, the first interval response was largest at the .83 UCS probability level. The CNV was more negative at the .50 UCS probability level than at the .17 and .83 UCS probability levels across the ISI. An early component of the CNV was also most negative at the .50 UCS probability level, and was larger at Cz than at Pz. A late CNV component did not differ significantly among UCS probability levels. It was concluded that the EDR and CNV reflect different properties of the associative process between paired stimuli.
Mathematical Models of the Event‐Related Potential
Authors: Hunt Earl 
Published: February 2007

ABSTRACTThe Event‐Related Potential is assumed to be composed of several underlying component waveforms. Principal Components Analysis is a statistical technique that has been used to uncover the components by analysis of the observed waveform. The mathematical assumptions behind Principal Components Analysis are examined, and their plausibility in the ERP application is questioned. The problem of plausibility is serious because Principal Components Analysis may not recover component waveforms accurately if the assumptions behind the method are violated. The nature of the inaccuracies is illustrated by an analysis of simulated waveforms constructed from known components.