Recent studies have demonstrated that positive and negative affective reactivity can be predicted by resting electroencephalographic (EEG) asymmetry in frontal brain regions. These studies used different methods to assess asymmetry and affectivity. The goal of the present study was a conceptual replication of these results and to investigate their independence of employed procedures. Resting EEG of 37 subjects was recorded and affective slides were presented to obtain ratings of subjects' emotional reactions. Different procedures were applied to the data to assess the relation between asymmetries and affective reactivity. Depending on the particular analysis procedure, there were associations between anterior asymmetry and affectivity in line with the published findings, opponent to those findings, or no relation between anterior asymmetry and affective reactivity.

Recent studies have demonstrated that positive and negative affective reactivity can be predicted by resting electroencephalographic (EEG) asymmetry in frontal brain regions. These studies used different methods to assess asymmetry and affectivity. The goal of the present study was a conceptual replication of these results and to investigate their independence of employed procedures. Resting EEG of 37 subjects was recorded and affective slides were presented to obtain ratings of subjects' emotional reactions. Different procedures were applied to the data to assess the relation between asymmetries and affective reactivity. Depending on the particular analysis procedure, there were associations between anterior asymmetry and affectivity in line with the published findings, opponent to those findings, or no relation between anterior asymmetry and affective reactivity.

Sleep-related vehicle accidents are prevalent early morning, especially in younger drivers. In two independent studies following a night of either restricted or nil sleep, young experienced drivers drove for 2 hr (0600–0800h) continuously in an immobile car on an interactive, computer-generated, dull, and monotonous roadway. This exercise followed ingestion (at 0530h) of 200 mg caffeine (= 2–3 cups coffee) versus placebo, counterbalanced, double blind. Driving incidents (lane drifting), subjective sleepiness, and 4–11 Hz electroencephalogram (EEG) activity were logged. In Study 1 (sleeping 0000–0500h), caffeine significantly reduced incidents and subjective sleepiness throughout the 2-hr drive, and EEG power for the second 30-min period. In Study 2 (no sleep), sleepiness affected all measures profoundly, and driving was terminated after 1 hr. Nevertheless, caffeine reduced incidents significantly for the first 30 min and subjective sleepiness for the hour. This caffeine dose, feasibly taken via coffee, effectively reduces early morning driver sleepiness for about 30 min following nil sleep, and for around 2 hr after sleep restriction.

Pupillary response to noxious stimulation was investigated in men (n = 11) and women (n = 9). Subjects experienced repeated trials of noxious electrical fingertip stimulation at four intensities, ranging from faint to barely tolerable pain. Measures included pupil dilation response (PDR), pain report (PR), and brain evoked potentials (EPs). The PDR began at 0.33 s and peaked at 1.25 s after the stimulus. Multivariate mixed-effects analyses revealed that (a) the PDR increased significantly in peak amplitude as stimulus intensity increased, (b) EP peaks at 150 and 250 ms differed significantly in both amplitude and latency across stimulus intensity, and (c) PR increased significantly with increasing stimulus intensity. Men demonstrated a significantly greater EP peak amplitude and peak latency at 150 ms than did women. With sex and stimulus intensity effects partialled out, the EP peak latency at 150 ms significantly predicted PR, and EP peak amplitude at 150 ms significantly predicted the PDR peak amplitude.

In the present study we evaluated the relationships between the P300 event-related potential and event-related desynchronization (ERD) of electroencephalographic alpha activity by simultaneously analyzing P300 as well as 7–10- and 10–14-Hz alpha ERD responses from auditory passive and active oddball conditions. We compared the effects of task (target vs. nontarget) and electrode (Fz, Cz, Pz) on P300 and ERD, and correlated P300 amplitude/latency with ERD maximal amplitude/latency across individuals. The major findings were that P300 as well as slow and fast alpha ERD manifested similar task and electrode effects. P300 preceded ERD and predicted individual variance of both slow and fast alpha ERD. The relationships of P300 with alpha ERD were different for the slow and fast alpha frequencies. These findings indicate that P300 and ERD are related such that slow and fast alpha ERDs are specifically guided or modified by the internal event(s) indexed by P300.

Reflexive eyeblinks to a startle probe vary with the pleasantness of affective pictures, whereas the corresponding P300 varies with emotional arousal. The impact of attention to the probe on these effects was examined by varying task and probe type. Probes were either nonstartling tones or startling noises presented during affective picture viewing. Half the participants performed a task requiring attention to the probes; the other participants were told to ignore the probes. Blinks to the startle probe varied with picture pleasantness for both task and nontask conditions. In contrast, P300 magnitudes for both startle and tone probes were reduced during emotionally arousing pictures, irrespective of pleasantness, in task and nontask conditions. Further, attending to the startle probe prompted an augmentation of N100 during unpleasant pictures. The data suggest that affective modulation of probe responses reflects obligatory processes in picture perception.

Brain mechanisms extracting invariant information from varying auditory inputs were studied using the mismatch-negativity (MMN) brain response. We wished to determine whether the preattentive sound-analysis mechanisms, reflected by MMN, are capable of extracting invariant relationships based on abstract conjunctions between two sound features. The standard stimuli varied over a large range in frequency and intensity dimensions following the rule that the higher the frequency, the louder the intensity. The occasional deviant stimuli violated this frequency–intensity relationship and elicited an MMN. The results demonstrate that preattentive processing of auditory stimuli extends to unexpectedly complex relationships between the stimulus features.

The P300 component and the oscillatory 4–7 Hz electroencephalographic activity of auditory event-related brain potentials (ERPs) were assessed to study differences between passive and oddball task conditions. Theta responses from 15 adults were analyzed for single-sweep amplitude, phase locking, and enhancement against prestimulus activity. ERPs were characterized by enhanced and strongly phase-locked theta oscillations in the early (0–300 ms) poststimulus epoch, with only the late (300–600 ms) theta responses at Fz and Pz affected by the oddball condition. P300 was strongly associated not only with the concurrent theta oscillations but also with the evoked theta activity preceding P300 (0–300 ms). It was concluded that single theta response parameters can reveal specific functional differences between passive and oddball conditions and that a strong relationship exists between the theta frequency component and the time domain P300 ERP component.

Crossmodal links in spatial attention were studied in an experiment where participants had to detect peripheral tactile or visual targets on the attended side, while ignoring all stimuli on the unattended side and in the currently irrelevant modality. Both relevant locations and relevant modalities were specified on a trial-by-trial basis by auditory precues. Spatial orienting in the cue–target interval was reflected in anterior negativities and occipital positivities contralateral to the cued side, either when vision or touch was cued as relevant. These effects resembled previously reported ERP modulations during shifts of visual attention, implicating supramodal mechanisms in the control of spatial attention and demonstrating their independence of cue modality. Early effects of spatial attention on somatosensory and visual ERPs were of equivalent size for currently relevant and irrelevant modalities. Results support the idea that crossmodal links in spatial attention are mediated by supramodal control mechanisms.

The P300 component and the oscillatory 4–7 Hz electroencephalographic activity of auditory event-related brain potentials (ERPs) were assessed to study differences between passive and oddball task conditions. Theta responses from 15 adults were analyzed for single-sweep amplitude, phase locking, and enhancement against prestimulus activity. ERPs were characterized by enhanced and strongly phase-locked theta oscillations in the early (0–300 ms) poststimulus epoch, with only the late (300–600 ms) theta responses at Fz and Pz affected by the oddball condition. P300 was strongly associated not only with the concurrent theta oscillations but also with the evoked theta activity preceding P300 (0–300 ms). It was concluded that single theta response parameters can reveal specific functional differences between passive and oddball conditions and that a strong relationship exists between the theta frequency component and the time domain P300 ERP component.

In the context of picture viewing, consistent and specific relationships have been found between two emotion dimensions (valence and arousal) and self-report, physiological and overt behavioral responses. Relationships between stimulus content and the emotion-response profile can also be modulated by the formal properties of stimulus presentation such as screen size. The present experiment explored the impact of another presentation attribute, stimulus motion, on the perceived quality of the induced emotion and on its associated physiological response pattern. Using a within-subject design, moving and still versions of emotion-eliciting stimuli were shown to 35 subjects while facial muscle, heart rate, skin conductance, and emotion self-reports were monitored. The impact of motion was dramatic. Self-report and physiological data suggested strongly that motion increased arousal, had little impact on valence, and captured and sustained the subject's attention to the image.

Although the generality of dyslexia and its devastating effects on the individual's life are widely acknowledged, its precursors and associated neural mechanisms are poorly understood. One of the two major competing views maintains that dyslexia is based primarily on a deficit in linguistic processing, whereas the other view suggests a more general processing deficit, one involving the perception of temporal information. Here we present evidence in favor of the latter view by showing that the neural discrimination of temporal information within complex tone patterns fails in dyslexic adults. This failure can be traced to early cortical mechanisms that process auditory information independently of attention.

Event-related potentials (ERPs) were elicited with auditory stimuli, and spectral analysis was performed on the poststimulus electroencephalographic (EEG) activity to assess how variables that influence the P300 affect spectral parameters of the resultant ERP. In Experiment 1, a no-stimulus condition was compared with a single repeated tone that was either ignored or counted. In Experiment 2, an auditory oddball paradigm was used in which the subject ignored all stimuli, counted only the target, or counted both the target and the standard stimuli in different conditions. In Experiment 3, stimulus probability was manipulated in separate conditions (.20, .50, .80), with the subject required to count the target stimulus. Delta and theta band spectral power increased whenever P300 amplitude increased. However, as the attentional requirements increased across tasks, alpha-1 and alpha-2 power and mean frequency increased. The findings indicate that auditory stimulus processing modulates the EEG more than just by adding ERP components to the epoch.

For almost two decades, researchers have demonstrated that hypertension is reliably associated with decreased perception of pain. More recently, a growing body of evidence has begun to suggest that hypoalgesia is not a consequence of high blood pressure, as the phenomenon precedes the onset of hypertension in individuals at risk for the disorder. This article provides a review of empirical evidence of decreased pain perception in normotensive persons with a family history of hypertension, elevated resting blood pressure, or exaggerated cardiovascular reactivity to stress. Based on the existing evidence, hypoalgesia is argued to be a correlate of dysregulation of central nervous system structures involved in both pain control and cardiovascular regulation in individuals who are genetically predisposed to develop high blood pressure. As such, hypoalgesia may serve as a valuable method of identifying individuals at greatest risk for hypertension.

To reveal areas in the central nervous system of importance for electrodermal control, regional cerebral blood flow (rCBF) was correlated to nonspecific skin conductance fluctuations (NSF) during aversive and nonaversive conditions. Participants viewed a TV screen displaying white noise or snake videotapes presented both with and without electric shocks given to the right hand. H215O positron emission tomography was used to measure rCBF, and the constant voltage technique was used to measure NSF from the left hand. Electrodermal activity was positively related to rCBF in the left primary motor cortex (MI, Brodmann's Area 4) and bilaterally in the anterior (Areas 24 and 32) and posterior cingulate cortex (Area 23). Negative relations were observed bilaterally in the secondary visual cortex (Areas 18 and 19) and the right inferior parietal cortex (Area 39), with a tendency also for the right insular cortex (Areas 13, 15, and 16). Because results from lesion and stimulation studies in humans converge with the present imaging results, we conclude that the cingulum and the motor cortex, in addition to the parietal and possibly the insular cortex, form part of one or several distributed neural network(s) involved in electrodermal control. Because these areas also support anticipation, affect, and locomotion, electrodermal responses seem to reflect cognitively or emotionally mediated motor preparation.

Behavioral studies have shown that two different morphed faces belonging to the same identity are harder to discriminate than two faces stemming from two different identities. The temporal course of this categorical perception effect has been explored through event-related potentials. Three kinds of pairs were presented in a matching task: (1) two different morphed faces representing the same identity (within), (2) two other faces representing two different identities (between), and (3) two identical morphed faces (same). Following the second face onset in the pair, the amplitude of the right occipitotemporal negativity (N170) was reduced for within and same pairs as compared with between pairs, suggesting an identity priming effect. We also observed a modulation of the P3b wave, as the amplitude of the responses for within pairs was higher than for between and same pairs, suggesting a higher complexity of the task for within pairs. These results indicate that categorical perception of human faces has a perceptual origin in the right occipitotemporal hemisphere.

The objective of the study was to assess the validity of an activity monitor (AM) within a psychophysiological study. The AM was based on four body-fixed accelerometers and discriminated postures, transitions, and dynamic activities. Three subjects participated in each of two 4-hr sessions. During each session, consisting of two protocols, ambulatory accelerometer and heart rate measurements were made. The output of the AM was compared with simultaneously recorded video tapes. An overall agreement between AM and video of 88 and 96% was found. The number of transitions and dynamic periods, and the duration of activities were well determined. Posture-related heart rate changes were demonstrated. A three-sensor configuration hardly influenced the validity scores. The AM appeared to be a valid instrument to quantify aspects of physical activity, and offers new possibilities for ambulatory psychophysiological research.

Electrophysiological effects of aerobic fitness and maximal aerobic exercise were investigated by comparing P300 and N400 before and after a maximal cycling test. Event-related potentials (ERPs) were obtained from 20 students divided into two matched groups defined by their aerobic fitness level (cyclists vs. sedentary subjects). The session of postexercise ERPs was performed immediately after body temperature and heart rate returned to preexercise values. At rest, no significant differences were observed in ERP parameters between cyclists and sedentary subjects. This finding argued against the hypothesis that ERP modifications may be directly assumed by aerobic fitness level. The postexercise session of ERPs showed a significant P300 amplitude increase and a significant P300 latency decrease in all subjects. Similarly, N400 effect increased significantly after the maximal exercise in all subjects. ERP changes were of the same magnitude in the two groups. The present study argues for a general arousing effect of maximal aerobic exercise, independently of the aerobic fitness level.

A longitudinal study (G. K. Kochanska, 1997) showed that temperamental fearfulness, assessed at toddler age via observational data and maternal ratings, moderated pathways to internalized conscience at age 4. For fearful children, maternal gentle discipline deemphasizing power predicted conscience development; for fearless children, attachment security predicted conscience development. Electrodermal reactivity assessed at age 4 on the same children was used as a physiological reflection of fearful temperament and was substituted for the earlier fearfulness measure to test the theoretical model. As expected, for electrodermally reactive children, maternal gentle discipline predicted conscience, whereas for nonreactive children, attachment security predicted conscience. The findings support the notions of (a) electrodermal reactivity at an early age as a correlate of temperament, (b) temperament as a moderator of socialization in early moral development, and (c) lovelessness in psychopathic individuals as an index of the failure of the alternative pathway (via attachment) to conscience in fearless children.

This study had two objectives: To examine poorly understood patterns of young children's electrodermal reactivity and to test the hypothesis that this reactivity reflects individual differences in the behavioral inhibition system (BIS). We recorded skin conductance responses (SCRs) from 92 4-year-old children during a laboratory session that encompassed physiological and psychological stimuli. Physiological stimuli (breaths), moderately loud to loud sounds (expected and unexpected) and, to a lesser extent, stimuli with psychological significance elicited clear SCRs. Induction of psychological conflict and exposure to emotional film clips for the most part did not elicit increases in skin conductance (SC). Children's temperament dimensions of fearfulness and effortful (or inhibitory) control—two components of the BIS—were assessed using robust observational batteries at age 2 and 4 years. The theoretically expected correlations between overall SC lability (reflecting SC levels) and both dimensions of temperament were significant, albeit modest and limited to the contemporaneous measures at age 4.