bluuebunny/crossref_metadata_2025 huggingface dataset:
Guidelines for using human event‐related potentials to study cognition: Recording standards and publication criteria
Authors: Picton T.W. , Bentin S. , Berg P. , Donchin E. , Hillyard S.A. , Johnson R. , Miller G.A. , Ritter W. , Ruchkin D.S. , Rugg M.D. , Taylor M.J.
Published: December 2004

Event‐related potentials (ERPs) recorded from the human scalp can provide important information about how the human brain normally processes information and about how this processing may go awry in neurological or psychiatric disorders. Scientists using or studying ERPs must strive to overcome the many technical problems that can occur in the recording and analysis of these potentials. The methods and the results of these ERP studies must be published in a way that allows other scientists to understand exactly what was done so that they can, if necessary, replicate the experiments. The data must then be analyzed and presented in a way that allows different studies to be compared readily. This paper presents guidelines for recording ERPs and criteria for publishing the results.
An evaluation of methods for single‐trial estimation of P3 latency
Authors: Jaśkowski Piotr , Verleger Rolf
Published: December 2004

This study investigated the validity of procedures for estimating the P3 complex in single trials. In “pseudo‐real” simulations of the N1‐P2 complex of the occipital visual‐evoked potential, Möcks, Köhler, Gasser, and Pham (1988) had reported that their maximum‐likelihood method (Pham, Möcks, Köhler, & Gasser, 1987) performed better than Woody's (1967) method. Using pseudo‐real simulations of auditory oddball data, we wanted to know whether this finding also held true for the P3 complex. The performance of three methods was studied: peak picking, Woody's method, and Pham et al.'s method (as well as an extension of this latter method). Performance of all methods critically depended on the signal‐to‐noise ratio. There was some advantage for the more sophisticated methods, particularly when signal‐to‐noise ratios were realistic. “Good” trials may be selected by all methods, to improve the signal‐to‐noise ratio, but this selection entails the risk of bias. Further research should investigate whether these conclusions also hold true when the P3 complex consists of more than one component.
Effects of paced respiration on heart period and heart period variability
Authors: Stark Rudolf , Schienle Anne , Walter Bertram , Vaitl Dieter
Published: December 2004

The present study investigated psychophysiological responses to paced respiration of different frequencies. Twenty men and 20 women (mean age: 24.3 years) underwent five breathing conditions (paced with 0.15 Hz, 0.20 Hz, 0.25 Hz, 0.30 Hz, and unpaced), each lasting 5 min. As dependent physiological measures heart period, and different heart period variability (HPV) parameters were assessed. Psychological variables consisted of mood estimates as well as rated accuracy and effort to follow the pacing rhythm. HPV decreased with higher breathing frequencies, under paced and unpaced conditions, whereas mood ratings did not change. Subjects indicated more effort and less accuracy in following the pacing signal, the more its frequency differed from their spontaneous breathing frequency. The comparison of a spontaneous breathing condition with a frequency‐matched paced condition revealed that pacing per se provoked a reduction in heart period. Because this decrease was not accompanied by changes in any of the HPV frequency components, their validity as measures of autonomic control needs to be questioned.
The respiratory‐related evoked potential: Effects of attention and occlusion duration
Authors: Webster Kate E. , Colrain Ian M.
Published: December 2004

The present study assessed the effects of occlusion duration and attention on components of the respiratory‐related evoked potential (RREP). Twenty‐nine channel evoked potential recordings were obtained from 12 young adults exposed to a pseudorandom sequence of 100‐, 200‐, 400‐, and 800‐ms inspiratory occlusions, under attend and ignore conditions. Results demonstrated that the duration of an inspiratory occlusion does not affect RREP components systematically, highlighting the importance of the onset of the occlusion in producing the cortical responses. Attention resulted in augmentation of the N1, P2, and P3 components but did not affect the early latency Nf and P1 components. P1, N1, and P3 occurred with shorter latencies in the attend condition. One subject with poor duration estimation ability displayed substantially delayed P3 latency. This result highlights the relationship between P3 and perception of respiratory somatosensory information.
Detecting the onset of the lateralized readiness potential: A comparison of available methods and procedures
Authors: Mordkoff J. Toby , Gianaros Peter J.
Published: December 2004

Studies that measure the onset of the lateralized readiness potential (LRP) could well provide researchers with important new data concerning the information‐processing locus of experimental effects of interest. However, detecting the onset of the LRP has proved difficult. The present study used computer simulations involving both human and artificial data, and both stimulus‐ and response‐locked effects, to compare a wide variety of techniques for detecting and estimating differences in the onset latency of the LRP. Across the two sets of simulations, different techniques were found to be the most accurate and reliable for the analysis of stimulus‐ and response‐locked data. On the basis of these results, it is recommended that regression‐based methods be used to analyze most LRP data.
The effects of caffeine on visual selective attention to color: An ERP study
Authors: Ruijter Judith , de Ruiter Michiel B. , Snel Jan
Published: December 2004

Event‐related potentials were recorded from 11 subjects after ingesting caffeine (250 mg) or placebo. Subjects were instructed to attend selectively to stimuli with a specified color (red or blue) in order to react to the occurrence of a target within the attended category. Reaction times revealed faster responses for the caffeine condition, whereas no differences in strategy were observed. Color attention effects were identified as frontal selection positivity, occipital selection negativity, and N2b, whereas target detection was reflected in P3b. Effects of treatment were found as a more positive‐going frontal P2 component in the caffeine condition. In addition, an interaction between attention and treatment could be observed on the N2b component. This pattern of results suggests that caffeine yields a higher overall arousal level, more profound processing of both attended and unattended information, and an acceleration of motor processes.
Suppression and enhancement of emotional responses to unpleasant pictures
Authors: Jackson Daren C. , Malmstadt Jessica R. , Larson Christine L. , Davidson Richard J.
Published: December 2004

Despite the prominence of emotional dysfunction in psychopathology, relatively few experiments have explicitly studied emotion regulation in adults. The present study examined one type of emotion regulation: voluntary regulation of short‐term emotional responses to unpleasant visual stimuli. In a sample of 48 college students, both eyeblink startle magnitude and corrugator activity were sensitive to experimental manipulation. Instructions to suppress negative emotion led to both smaller startle eyeblinks and decreased corrugator activity. Instructions to enhance negative emotion led to larger startle eyeblinks and increased corrugator activity. Several advantages of this experimental manipulation are discussed, including the use of both a suppress and an enhance emotion condition, independent measurement of initial emotion elicitation and subsequent regulation of that emotion, the use of a completely within‐subjects design, and the use of naturalistic emotion regulation strategies.
Effects of nicotine and caffeine, separately and in combination, on EEG topography, mood, heart rate, cortisol, and vigilance
Authors: Gilbert David G. , Dibb William D. , Plath Louisette C. , Hiyane Steven G.
Published: December 2004

Effects of nicotine and caffeine, separately and in combination, were assessed in 12 male habitual smokers in a repeated‐measures design. Caffeine (0‐mg vs. two 150‐mg doses administered in a decaffeinated/sugar‐free cola drink post‐baseline and 90 min later) was crossed with nicotine (ad libitum own dosing vs. 1.0‐mg machine‐delivered dose vs. 0.05‐mg machine‐delivered dose). Participants smoked a total of five cigarettes at 30‐min intervals over a 2‐hr period. Caffeine and nicotine had large effect sizes on electroencephalogram (EEG) power; however, these effects were modulated by the eyes open versus closed condition, the other drug, and electrode site. EEG effects of open versus closed eyes tended to be of the same size and direction as those of nicotine and caffeine. However, whereas nicotine increased EEG power in some higher frequency bands in some conditions, caffeine decreased EEG power across almost all conditions. Serum cortisol concentration, vigor, and pleasantness were increased by nicotine, but not by caffeine. Level of depressive mood depended on an interaction of caffeine and nicotine. Vigilance performance was enhanced significantly by caffeine and was increased almost significantly by nicotine. The findings were interpreted in terms of common and differential mechanisms of the two drugs.
Short duration power changes in the EEG during recognition memory for words and faces
Authors: Burgess A.P. , Gruzelier J.H.
Published: December 2004

Although memory has been widely studied using event‐related potentials, memory‐related changes in the electroencephalogram (EEG) have been relatively neglected. The aim of this study was to determine whether evidence could be found for memory‐related changes in the EEG. EEG was recorded from a sample of healthy volunteers while they performed word and face recognition memory tasks. Data were analyzed using the method of event‐related desynchronization. In the theta frequency range there was a short‐duration increase in power that occurred in the first 250 ms that was maximal at temporal sites (T5/T6). For words, but not faces, there was a repetition effect in theta such that new words elicited greater synchronization than old words at the midline frontal electrode (Fz). In the alpha frequency range there was a lateralized repetition effect, which occurred from 750 ms. In upper alpha this effect was lateralized in the expected way with greater desynchronization at temporo‐parietal sites on the left for words and on the right for faces. For lower alpha, the lateralization was reversed. The meanings of these findings are interpreted in the light of existing models of recognition memory.
Secretory immunoglobulin A and cardiovascular reactions to mental arithmetic, cold pressor, and exercise: Effects of alpha‐adrenergic blockade
Authors: Ring Christopher , Harrison Lesley K. , Winzer Alexandra , Carroll Douglas , Drayson Mark , Kendall Martin
Published: December 2004

The mechanism underlying acute changes in secretory immunoglobulin A (sIgA) remains to be determined. In this experiment, sIgA and cardiovascular activity were monitored at rest and while participants performed a mental arithmetic task, cold pressor, and submaximal cycle exercise following placebo or 1 mg of the alpha‐adrenergic blocker, doxazosin. Under placebo, the tasks produced patterns of cardiovascular activity indicative of combined alpha‐ and beta‐adrenergic, alpha‐adrenergic, and beta‐adrenergic activation, respectively. Doxazosin was associated with reduced blood pressure during cold pressor, but not during arithmetic or exercise. Mental arithmetic elicited increases in sIgA concentration and exercise produced increases in both sIgA concentration and secretion rate; these changes were unaffected by alpha blockade. In contrast, the cold pressor was associated with decreases in both sIgA concentration and secretion rate, which were blocked by doxazosin. These data suggest that acute decreases, but not increases, in sIgA are mediated by alpha‐adrenergic mechanisms.
Event‐related brain potential and heart rate manifestations of visual selective attention
Authors: van der Veen Frederik M. , Lange Jan J. , van der Molen Maurits W. , Mulder Gijsbertus , Mulder Lambertus J.M.
Published: December 2004

Twenty‐eight volunteers were instructed to attend stimuli presented at one side of the computer screen and to ignore stimuli presented at the other side. Both attended and unattended stimulus series consisted of targets (25%) and nontargets (75%) defined on the basis of stimulus shape. Attended targets required a binary choice based on stimulus color. Selective attention led to the expected increase in both midlatency (N2b) and late (P3) brain potential components. Furthermore, selective attention led to increased anticipatory cardiac slowing preceding the target stimulus and to increased primary bradycardia. Correlational analyses revealed a positive relation between the effects of selective attention on N2b amplitude and primary bradycardia suggestive of cortical involvement in the chronotropic control of heart rate.
An event‐related brain potential study of cross‐modal links in spatial attention between vision and touch
Authors: Eimer Martin , Driver Jon
Published: December 2004

Event‐related potential (ERP) evidence for the existence of cross‐modal links in endogenous spatial attention between vision and touch was obtained in an experiment where participants had to detect tactile or visual targets on the attended side and to ignore the irrelevant modality and stimuli on the unattended side. For visual ERPs, attentional modulations of occipital P1 and N1 components were present when attention was directed both within vision and within touch, indicating that links in spatial attention from touch to vision can affect early stages of visual processing. For somatosensory ERPs, attentional negativities starting around 140 ms poststimulus were present at midline and lateral central electrodes when touch was relevant. No attentional somatosensory ERP modulations were present when vision was relevant and tactile stimuli could be entirely ignored. However, in another task condition where responses were also required to infrequent tactile targets regardless of their location, visual‐spatial attention modulated somatosensory ERPs. Unlike vision, touch apparently can be decoupled from attentional orienting within another modality unless it is potentially relevant.
The effects of change in lead stimulus modality on the modulation of acoustic blink startle
Authors: Lipp Ottmar V. , Siddle David A.T. , Dall Patricia J.
Published: December 2004

In two experiments we investigated the effect of generalized orienting induced by changing the modality of the lead stimulus on the modulation of blink reflexes elicited by acoustic stimuli. In Experiment 1 (n= 32), participants were presented with acoustic or visual change stimuli after habituation training with tactile lead stimuli. In Experiment 2 (n= 64), modality of the lead stimulus (acoustic vs. visual) was crossed with experimental condition (change vs. no change). Lead stimulus change resulted in increased electrodermal orienting in both experiments. Blink latency shortening and blink magnitude facilitation increased from habituation to change trials regardless of whether the change stimulus was presented in the same or in a different modality as the reflex‐eliciting stimulus. These results are not consistent with modality‐specific accounts of attentional startle modulation.
Motor and nonmotor event‐related potentials during a complex processing task
Authors: Hillman Charles H. , Apparies Ross J. , Hatfield Bradley D.
Published: December 2004

Identification of the necessary stimulus properties to elicit the stimulus preceding negativity (SPN) has been the impetus for numerous research studies. The current study was conducted to explore the possibility that the SPN is an index of cognitive resource allocation. An auditory warning stimulus (S1) indicated whether an easy or difficult discrimination would occur at S2. The SPN was collected before a nonmotor discrimination task (S2) that consisted of identifying the higher of two bars. To eliminate the influence of motor processing prior to S2, a button press on the side of the higher bar was held until perception of a response cue (S3). Additionally, P3, contingent negative variation (CNV), and behavioral measures were collected to assist in assessing the SPN. Results indicated that although the SPN exhibited increased negativity, no differences were observed based on task difficulty. However, task difficulty did affect P3 data for both the warning tone and the discrimination task, an effect not observed for the CNV. Overall, the data did not support that hypothesis that the SPN provides an index of cognitive demand.
An electrophysiological index of stimulus unfamiliarity
Authors: Daffner Kirk R. , Mesulam M. Marsel , Scinto Leonard F.M. , Calvo Vivian , Faust Robert , Holcomb Phillip J.
Published: December 2004

This study investigated the functional significance of the N2 response to novel stimuli. In one condition, background, target, and deviant stimuli were simple geometric figures. In a second condition, all stimulus types were unfamiliar/unusual figures. In a third condition, background and target stimuli were unusual figures and deviant stimuli were simple shapes. Unusual figures, whether they were deviant, target, or background stimuli, evoked larger N2 responses than their simple, familiar counterparts. N2 elicited by an unusual background stimulus was larger than that evoked by simple, deviant stimuli, a pattern opposite that exhibited by the subsequent P3. Deviance from immediate context had limited influence over N2 amplitude. The results suggest that novelty N2 and novelty P3 reflect the processing of different aspects of “novel” visual stimuli. The novelty P3 is particularly sensitive to deviation from immediate context. In contrast, the novelty N2 is sensitive to deviation from long‐term context that renders a stimulus unfamiliar and difficult to encode.
Cardiovascular reactivity and adaptation to recurrent psychological stress: The moderating effects of evaluative observation
Authors: Kelsey Robert M. , Blascovich Jim , Leitten Christopher L. , Schneider Tamera R. , Tomaka Joe , Wiens Stefan
Published: December 2004

The impact of evaluative observation on cardiovascular reactivity and adaptation to recurrent psychological stress was evaluated in 162 undergraduate men and women. All participants performed three mental arithmetic tasks with or without evaluative observation. Impedance cardiographic, blood pressure, task performance, and stress appraisal measures were recorded for each task. Evaluative observation moderated the effects of task repetition on cardiac reactivity but not vascular reactivity. The introduction of evaluative observation disrupted cardiac adaptation, resulting in a resurgence of β‐adrenergic cardiac reactivity (p < .005), whereas the removal of evaluative observation promoted cardiac adaptation. Evaluative observation also increased stress appraisals and slowed task performance. The results support the dual process theory of habituation, rather than stimulus comparator theory, but only partially support cognitive appraisal theory.
Rate of force development and the lateralized readiness potential
Authors: Ray William J. , Slobounov Semyon , Mordkoff J. Toby , Johnston J. , Simon Robert F.
Published: December 2004

We examined the relationship between force and rate of force development aspects of movement dynamics and electroencephalogram motor components as reflected in the lateralized readiness potential (LRP). Using self‐paced tasks, in Studies 1 and 3 we investigated whether differential speed and accuracy constraints in discrete and repetitive finger force production tasks influenced the LRP. These studies showed that speed tasks produced larger LRP than accuracy tasks regardless of whether the movement type was discrete or repetitive. In Studies 2 and 4 we studied four conditions with two levels of force and two levels of rate of force development. The largest LRPs were found with the greatest rate of force development. Overall, the four studies demonstrated that preparation for differential rates of force development is a major component reflected in the LRP.
Scalp recorded direct current potential shifts associated with quenching thirst in humans
Authors: Schmitt B. , Mölle M. , Marshall L. , Born J.
Published: December 2004

As an indicator of cortical excitability, direct current (DC) potentials were recorded from thirsted subjects before, during and after drinking 400 ml of water. Self‐rated thirst was distinctly reduced after drinking. Compared with control conditions in which the subjects remained thirsty, during drinking a widespread negative potential shift occurred averaging over −70 μV at Cz. At the transition from the consumatory phase to the postconsumption phase, a slow positive potential shift commenced that was most pronounced over the anterior cortex (averaging over +40 μV at Fz) and persisted for more than 3 min after drinking. Control conditions excluded muscle activity, ocular movements, and changes in body fluid and serum osmolality as possible non‐neuronal sources of the DC‐potential changes. The sequence of negative and positive potential shifts associated with drinking indicates a coordinate regulation of cortical excitability that may facilitate consumatory behavior and its context‐dependent encoding into memory.
Mismatch negativity in children and adults, and effects of an attended task
Authors: Gomes Hilary , Molholm Sophie , Ritter Walter , Kurtzberg Diane , Cowan Nelson , Vaughan Herbert G.
Published: December 2004

Attention has been shown to modulate the amplitude of the mismatch negativity (MMN) elicited by a small deviation in auditory stimuli in adults. The present study examined the effects of attention and deviant size on MMN amplitude in children. Children and adults were presented with sequences of tones containing standards (1000 Hz) and three deviants varying in degree of deviance from the standard (1050, 1200, and 1500 Hz). Tones were presented in three conditions: (1) while participants ignored them; (2) while participants listened to them and responded to all three deviants; and (3) while participants again ignored them. We found that the MMNs elicited by the hard deviant (1050 Hz) were larger when the children were actively discriminating the stimuli than when they were ignoring them. However, the MMNs elicited by the easy and medium deviants (1500 and 1200 Hz, respectively) in the children and by all three deviants in the adults were not affected by attention.
The perception of speech sounds by the human brain as reflected by the mismatch negativity (MMN) and its magnetic equivalent (MMNm)
Authors: Näätänen Risto
Published: December 2004

The present article outlines the contribution of the mismatch negativity (MMN), and its magnetic equivalent MMNm, to our understanding of the perception of speech sounds in the human brain. MMN data indicate that each sound, both speech and nonspeech, develops its neural representation corresponding to the percept of this sound in the neurophysiological substrate of auditory sensory memory. The accuracy of this representation, determining the accuracy of the discrimination between different sounds, can be probed with MMN separately for any auditory feature (e.g., frequency or duration) or stimulus type such as phonemes. Furthermore, MMN data show that the perception of phonemes, and probably also of larger linguistic units (syllables and words), is based on language‐specific phonetic traces developed in the posterior part of the left‐hemisphere auditory cortex. These traces serve as recognition models for the corresponding speech sounds in listening to speech. MMN studies further suggest that these language‐specific traces for the mother tongue develop during the first few months of life. Moreover, MMN can also index the development of such traces for a foreign language learned later in life. MMN data have also revealed the existence of such neuronal populations in the human brain that can encode acoustic invariances specific to each speech sound, which could explain correct speech perception irrespective of the acoustic variation between the different speakers and word context.
Working memory constraints on syntactic processing: An electrophysiological investigation
Authors: Vos Sandra H. , Gunter Thomas C. , Kolk Herman H.J. , Mulder Gijsbertus
Published: December 2004

Event‐related potentials (ERPs) and reaction times (RTs) were used to study how the processing of sentences with morphosyntactic violations is constrained by working memory (WM) capacity. The available WM capacity was varied by three orthogonal manipulations: (1) syntactic complexity; (2) additional WM load; and (3) verbal WM span. The processing of the morphosyntactic violations was reflected in longer RTs in ungrammatical compared with grammatical sentences, and in an anterior negativity and a centroparietal positivity in the ERPs. While the behavioral grammaticality effect was not influenced by the WM manipulations, the ERP effects were. The amplitude of the anterior negativity was modulated by the combination of complexity and load, and by WM span. The onset of the centroparietal positivity was delayed in the high‐load condition, and for the low‐span group. ERPs over the course of the sentences showed a frontal negative slow wave under high WM load, largest for the low‐span group. The finding that online syntactic processing is related to WM span and to additional WM load does not support the theory that there is a WM capacity specific for syntactic processing.
Striking a chord: Moods, blood pressure, and heart rate in everyday life
Authors: Shapiro David , Jamner Larry D. , Goldstein Iris B. , Delfino Ralph J.
Published: December 2004

The objective of this study was to assess the relation between the intensity of single moods and of mood combinations on blood pressure (BP) and heart rate (HR). The subjects were 203 healthy registered nurses, all women, who were studied on two work and two off days. Ambulatory BP and HR were recorded every 20 min. On each occasion subjects rated their moods on a 5‐point scale. Graded increases in BP and HR were shown with higher ratings of negative moods and decreases for a mood related to energy level. Little change was observed for a positive mood. These effects depended on concurrent changes in other moods. A positive mood countered the effects of a negative mood, whereas two negative moods resulted in unique patterns of BP and HR. The energy level mood moderated the cardiovascular effects of positive and negative moods. Ambulatory methods provide a way of probing into the nature and consequences of everyday emotional experiences.
Emotional reactions in children: Verbal, physiological, and behavioral responses to affective pictures
Authors: McManis Mark H. , Bradley Margaret M. , Berg W. Keith , Cuthbert Bruce N. , Lang Peter J.
Published: December 2004

Many studies have shown a consistent pattern in adults' responses to affective pictures and there is growing evidence of gender differences, as well. Little is known, though, about children's verbal, behavioral, and physiological responses to affective pictures. Two experiments investigated children's responses to pictures. In Experiment 1, children, adolescents, and adults viewed pictures varying in affective content and rated them for pleasure, arousal, and dominance. Results indicated that children and adolescents rated the pictures similarly to adults. In Experiment 2, physiological responses, self‐report, and viewing time were measured while children viewed affective pictures. As with adults, children's responses reflected the affective content of the pictures. Gender differences in affective evaluations, corrugator activity, skin conductance, startle modulation, and viewing time indicated that girls were generally more reactive to unpleasant materials.
The effects of age and gender on sleep EEG power spectral density in the middle years of life (ages 20–60 years old)
Authors: Carrier Julie , Land Stephanie , Buysse Daniel J. , Kupfer David J. , Monk Timothy H.
Published: December 2004

The effects of age and gender on sleep EEG power spectral density were assessed in a group of 100 subjects aged 20 to 60 years. We propose a new statistical strategy (mixed‐model using fixed‐knot regression splines) to analyze quantitative EEG measures. The effect of gender varied according to frequency, but no interactions emerged between age and gender, suggesting that the aging process does not differentially influence men and women. Women had higher power density than men in delta, theta, low alpha, and high spindle frequency range. The effect of age varied according to frequency and across the night. The decrease in power with age was not restricted to slow‐wave activity, but also included theta and sigma activity. With increasing age, the attenuation over the night in power density between 1.25 and 8.00 Hz diminished, and the rise in power between 12.25 and 14.00 Hz across the night decreased. Increasing age was associated with higher power in the beta range. These results suggest that increasing age may be related to an attenuation of homeostatic sleep pressure and to an increase in cortical activation during sleep.
Psychophysiological characteristics of narcissism during active and passive coping
Authors: Kelsey Robert M. , Ornduff Sidney R. , McCann Christina M. , Reiff Sarah
Published: December 2004

This study provides the first psychophysiological analysis of narcissism by measuring autonomic responses during active and passive anticipatory coping in 40 undergraduate men who scored high or low on the Narcissistic Personality Inventory (NPI). Compared to the low NPI group, the high NPI group showed greater preejection period (PEP) shortening, cardiac deceleration, and skin conductance response (SCR) habituation during anticipation of an aversive stimulus (p < .02). As expected, SCR and PEP reactivity were greater during active than passive coping. In the case of PEP, this effect emerged only in the low NPI group; the high NPI group showed the greatest PEP reactivity during the first task, regardless of coping demands. These data support hypothesized relationships among narcissism, psychopathy, and psychological predictors of cardiovascular disease, and suggest that a psychobiological dimension may underlie important features of narcissism.
Event‐related potentials and comorbidity in alcohol‐dependent adult males
Authors: Malone Stephen M. , Iacono William G. , McGue Matt
Published: December 2004

The present study examined event‐related potentials (ERPs) elicited by a visual discrimination task in a community sample of adult males with a lifetime diagnosis of alcohol dependence. Study participants were subtyped by the presence of additional comorbid disorders (antisocial personality, depression, and drug abuse or dependence). In all groups of alcohol‐dependent subjects, even those without any additional comorbid disorders, P3 amplitude differed from that of a comparison group. Alcohol‐dependent subjects with a diagnosis of illicit drug abuse or dependence, especially if they had antisocial personality as well, had the smallest amplitude responses. The amplitude profile of the P3 across the parietal electrodes used as active sites was flattened among alcoholic subjects, with P3 amplitude disproportionately reduced at the midline. Among alcoholic subjects with a lifetime diagnosis of depression, the flattened amplitude profile was due to elevated mean amplitude of the P3 at lateral leads, especially P4, relative to the comparison group. Alterations in ERP responses appear to be a general characteristic of alcoholism in men, although the presence of other comorbid disorders, particularly drug abuse or dependence together with antisocial personality, results in the greatest reductions in P3 amplitude.
The misclassification of blinks as saccades: Implications for investigations of eye movement dysfunction in schizophrenia
Authors: Calkins Monica E. , Katsanis Joanna , Hammer Micah A. , Iacono William G.
Published: December 2004

It is important to have a simple, accurate method for recording eye movements. Of the two popular approaches commonly adopted, electro‐oculography (EOG) and infrared oculography (IROG), IROG is often accepted as the more accurate, and it is the method that is currently used most frequently to examine eye movements in schizophrenia. This study investigated whether the misclassification of blinks as saccades affects saccade rates when the presence of a blink is determined using only IROG recordings of eye position. Both vertical electro‐oculography (VEOG), which can be used to objectively identify blinks, and IROG were recorded while 17 schizophrenia patients and 19 healthy controls were presented with sinusoidal stimuli. Of the blinks identified with the VEOG for the total group of participants, a substantial number (37%) were misclassified as catch‐up and anticipatory saccades when only the IROG was used. Furthermore, in the schizophrenia group, but not in the healthy control group, the use of the IROG led to a significant misclassification of blinks as anticipatory saccades. Therefore, when IROG alone is used to identify blinks, the misclassification of blinks as saccades is likely to introduce measurement error into estimates of saccade rates, particularly estimates of anticipatory saccade rates in schizophrenia patients.
Voluntary facial expression and hemispheric asymmetry over the frontal cortex
Authors: Coan James A. , Allen John J.B. , Harmon‐Jones Eddie
Published: December 2004

Brain activity was monitored while 36 participants produced facial configurations denoting anger, disgust, fear, joy, and sadness. EEG alpha power was analyzed during each facial pose, with facial conditions grouped according to the approach/withdrawal motivational model of emotion. This model suggests that “approach” emotions are associated with relatively greater left frontal brain activity whereas “withdrawal” emotions are associated with relatively greater right frontal brain activity. In the context of a bilateral decrease in activation, facial poses of emotions in the withdrawal condition resulted in relatively less left frontal activation in the lateral‐frontal, midfrontal and frontal‐temporal‐central region, but not in the parietal region, as predicted. Findings in the approach condition were less consistently supportive of predictions of the approach/withdrawal model. Implications for the approach/withdrawal model and for the emotion eliciting potential of voluntary facial movement are discussed.
Neural substrates for visual perceptual grouping in humans
Authors: Han Shihui , Song Yan , Ding Yulong , Yund E. William , Woods David L.
Published: December 2004

Two experiments investigated the neural mechanisms of Gestalt grouping by recording high‐density event‐related brain potentials (ERPs) during discrimination tasks. In Experiment 1, stimulus arrays contained luminance‐defined local elements that were either evenly spaced or grouped into columns or rows based on either proximity or similarity of shape. Proximity grouping was indexed by a short‐latency positivity (110–120 ms) over the medial occipital cortex and a subsequent right occipitoparietal negativity. Grouping by similarity was reflected only in a long‐latency occipitotemporal negativity. In Experiment 2, proximity grouping was examined when local elements were defined by motion cues, and was again associated with a medial occipital positivity. However, the subsequent long‐latency negativity was now enhanced over the left posterior areas. The implications of these results to the neural substrates subserving different grouping processes are discussed.
Hyperventilation beyond fight/flight: Respiratory responses during emotional imagery
Authors: van Diest Ilse , Winters Winnie , Devriese Stephan , Vercamst Elke , Han Jiang N. , van de Woestijne Karel P. , van den Bergh Omer
Published: December 2004

Hyperventilation (HV) is often considered part of a defense response, implying an unpleasant emotion (negative valence) combined with a strong action tendency (high arousal). In this study, we investigated the importance of arousal and valence as triggers for HV responses. Forty women imagined eight different scripts varying along the arousal and valence dimensions. The scripts depicted relaxation, fear, depressive, action, and desire situations. After each trial, the imagery was rated for valence, arousal, and vividness. FetCO2, inspiratory and expiratory time, tidal volume, and pulse rate were measured in a nonintrusive way. FetCO2 drops and decreases in inspiratory and expiratory time occurred in all but the depressive and the relaxation scripts, suggesting that a defense conceptualization of hyperventilation is not always appropriate.
Changes in the scalp topography of event‐related potentials and behavioral responses during the sleep onset period
Authors: Cote Kimberly A. , de Lugt Duncan R. , Campbell Kenneth B.
Published: December 2004

Event‐related potentials (ERPs) and behavioral responsiveness were investigated during the transition from wakefulness to sleep. Ten participants were presented with an auditory oddball task during repeated sleep onset periods. The EEG was recorded from 29 different scalp sites. A 1500‐Hz tone pip was presented infrequently (p= .04) within a series of lower pitch 1000‐Hz “standard” stimuli (p= .96). Participants were required to button press upon detection of the rare “target” stimulus. During wakefulness, almost all targets were detected. A large amplitude P300 was observed to these detected targets. This P300 was maximum over parietal areas of the scalp. During stage 1 sleep, subjects continued to respond on 47% of trials. The parietal P300 amplitude remained large to these detected targets. It was, however, much attenuated at frontal sites. When the participant failed to detect the target in either stage 1 or 2, no P300 was visible. P300 is thus associated with behavioral detection of the target stimulus, whether in wakefulness or stage 1 “sleep.” Trials were also sorted by reaction time (RT), in which bins 1–3 represented increasingly long RT. In the waking state, P300 amplitude did not significantly vary across the different bins. Although mean RT latency varied by 512 ms from bin 1 to bin 3, P300 latency varied by only 25 ms. Differences in RT are thus probably due to response‐related processes rather than stimulus classification time.
Reduced sensory anticipation in migraine
Authors: Mulder Elles J.C.M. , Linssen Wim H.J.P. , de Geus Eco J.C.
Published: December 2004

We examined differences between migraine patients and matched healthy controls in anticipatory processes preceding a warning stimulus and preceding a response stimulus during a forewarned choice reaction time task. We manipulated stimulus preceding negativity (SPN) by inserting full response information either at the instant of the warning stimulus (cue) or at the instant of the response stimulus. In contrast to control subjects, migraineurs with aura show low anticipation towards an informative cue and high anticipation towards a noninformative cue. Migraineurs without aura showed a cortical hypoactivation during motor preparation prior to the response stimulus. We propose a functional deficiency within frontal structures or the anterior cingulate cortex in migraine. This might explain the reduced anticipation, as well as the slow responses during selective attention that we previously reported in these patients.
Cardiovascular incentive effects where a challenge is unfixed: Demonstrations involving social evaluation, evaluator status, and monetary reward
Authors: Wright Rex A. , Killebrew Karen , Pimpalapure Dipti
Published: December 2004

Cardiovascular effects of social evaluation, evaluator status, and monetary reward were examined in participants presented with a challenge that allowed them to work as hard as they pleased (unfixed conditions) or called for a low level of effort (fixed conditions). In Experiment 1, evaluation was found to potentiate systolic pressure and heart rate responses insofar as the evaluator had status where the challenge was unfixed, but to have no impact on the responses where the challenge was fixed. In Experiment 2, reward value was found to potentiate the responses where the challenge was unfixed, but not where it was fixed. The main findings confirm and extend results from a previous experiment, and broaden the base of empirical support for the suggestion that active coping will be proportional to success importance where performance is unconstrained.
Omission evoked potentials (OEPs) in rats and the effects of diazepam
Authors: Jongsma Marijtje L.A. , Coenen Anton M.L. , van Rijn Clementina M.
Published: December 2004

We investigated whether evoked potentials to omitted stimuli could be measured in rats. Such an animal model would provide a measure of aspects of information processing concerned with expectancy and time estimation. In a first experiment, omission evoked potentials (OEPs) were elicited in rats by omitting stimuli (10%) from a train of tone pips with a fixed ISI (3 s). A control session consisted of omitting stimuli (10%) from a train of tone pips with a variable ISI (2.5–3.5 s). In a second experiment, OEPs were measured in rats that received 4 mg·kg−1 diazepam or vehicle sc. In the first experiment, half of the animals showed OEPs that consisted of a late‐latency positive wave, the other rats showed a slow negative drift. No OEPs were found in the control session. Rats showing OEPs consisting of a positive wave in Experiment 1 were passed to Experiment 2. In the vehicle condition of the second experiment, all rats showed OEPs. In the diazepam condition no OEPs were found. We found that OEPs can be measured in rats. In addition, OEPs are disrupted by diazepam. We propose that OEPs provide an elegant tool to elicit selectively endogenous EP components.
Effects of a dual task on the N100–P200 complex and the early and late Nd attention waveforms
Authors: Singhal Anthony , Doerfling Paul , Fowler Barry
Published: December 2004

The roles of N100 and the early and late negative difference (Nd) waveforms in selective attention were investigated with primary simulated flying and secondary dichotic listening tasks. Twenty highly trained participants performed the two tasks together, either while detecting secondary task deviant tones in one ear and ignoring tones in the other ear (dual condition) or while ignoring the tones in both ears (ignore condition). The amplitude of the N100–P200 complex in both the dual‐task and ignore conditions was reduced equally in the attended and unattended ear by the introduction of the primary task. In the dual‐task condition, the amplitude of the late Nd but not the early Nd was reduced by a combination of the introduction of the primary task and an increase in its difficulty. P300 showed the same amplitude pattern as the late Nd. We propose that the reduction in N100–P200 amplitude reflects an automatic gating mechanism. The dissociation of the early and late Nd suggests that the latter is not modality specific. The question is raised whether the late Nd is more closely associated with P300 than with the early Nd.
Brain mechanisms of visual encoding and working memory in psychometrically identified schizotypal individuals and after acute administration of haloperidol
Authors: Kopp Bruno , Wolff Monika , Hruska Claudia , Reischies Friedel M.
Published: December 2004

A probabilistic association task that manipulated the necessity to temporarily store information was combined with the recording of event‐related potentials. In Experiment 1, scores obtained from a positive schizotypy scale were used to categorize participants as either low or high schizotypal individuals. Low, but not high, schizotypal individuals displayed evidence for selective associative learning in the working memory dependent (“trace”) version of the task. The amplitudes of the occipito‐temporal N150 were attenuated in high schizotypal individuals. In Experiment 2, the intravenous administration of a single dose of haloperidol (0.04 mg/kg), but not of a placebo, strengthened the selectivity of associative learning in the trace version of the task. The amplitudes of the occipito‐temporal N150 were augmented by haloperidol. Psychometrically identified schizotypal individuals and normal individuals under mild stress demonstrated defective prioritization of information in working memory and deficient visual encoding. These neurocognitive effects of schizotypy and stress seem to be mediated by the D2 family of dopamine receptors.
Influence of preparatory schema on the speed of responses to spatially compatible and incompatible stimuli
Authors: Jennings J. Richard , van der Molen Maurits W. , van der Veen Frederik M. , Debski Kay B.
Published: December 2004

We investigated the inhibitory regulation of perceptual–motor processing streams in a task that switched between spatially compatible and incompatible stimulus–response mappings. Thirty male and female college‐aged participants performed a reaction time (RT) task in which the response was either spatially compatible or not depending on a cue immediately preceding the stimulus. The cue‐to‐stimulus interval (CI) was either 50 or 500 ms. Incompatible mapping yielded the typical slower responses than compatible mapping at 500 ms, but not at 50 ms. Changes in cardiac interbeat interval (IBI) and performance suggested that automatic responses to compatible stimuli were suppressed at 50 ms. Both performance and IBI changes as well as individual differences in these measures suggested a precue preparatory schema or set biased toward suppressing the compatible mapping. An alternate hypothesis of a cue‐induced suppression was questioned. The results illustrate the operation of different supervisory processes in the anticipatory and online control of action.
The human nociceptive flexion reflex threshold is higher during systole than diastole
Authors: Edwards Louisa , McIntyre David , Carroll Douglas , Ring Christopher , Martin Una
Published: December 2004

A baroreflex mechanism may explain hypertensive hypoalgesia. At rest, arterial baroreceptors are stimulated during the systolic upstroke of the pressure pulse wave. This study examined the effects of naturally occurring variations in baroreceptor activity during the cardiac cycle on an objective measure of pain, the nociceptive flexion reflex (NFR). Two interleaved up–down staircase procedures determined separate NFR thresholds during systole and diastole in 36 healthy, normotensive young adults. On odd‐numbered trials, the sural nerve was stimulated electrocutaneously at R + 300 ms whereas on even‐numbered trials, stimulation was delivered at R + 600 ms. The NFR threshold was higher at R + 300 ms than R + 600 ms. In contrast, stimulus intensity ratings did not differ between R + 300 ms and R + 600 ms. Stimulation of baroreceptors by natural increases in blood pressure during the systolic phase of the cardiac cycle was associated with dampened nociception.