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.

Research studies have found that smooth pursuit eye movement dysfunction may serve as an index of genetic liability to develop schizophrenia. The heritability of various measures of smooth pursuit eye tracking proficiency and the saccades that occur during smooth pursuit was examined in 64 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs. Two age cohorts were assessed (11–12 and 17–18 years of age). Intraclass correlations indicated significant similarity in the MZ twins for almost all measures in both age cohorts, whereas few of the DZ twin correlations attained significance. Biometrical modeling indicated that genetic mechanisms influence performance on both global and specific eye tracking measures, accounting for about 40% to 60% of the variance. These findings suggest that the underlying brain systems responsible for smooth pursuit and saccade generation during pursuit are under partial genetic control.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Event-related potentials were recorded to investigate the mechanisms of hierarchical processing and level-repetition effect. Participants identified targets that appeared at global, local, or both levels of hierarchical patterns. Reaction times showed global precedence and level-repetition effects. An occipital P1 wave was enhanced to local relative to global targets. The P1 to local targets was also larger when preceded by global than local targets. Global and both-level target selections were indexed by two posterior negativities peaking at 130 and 190 ms poststimulus, whereas local target selection was indexed by a broad occipitotemporal negativity. A late selection positivity was observed over the left occipitotemporal site for global targets but over the central site for local targets. The findings suggest that sensory-perceptual mechanisms contribute to global precedence and level-repetition effects in hierarchical processing.

This study investigated the relationship between resistive load magnitude, load magnitude estimation, and the respiratory-related evoked potential. In Part 1, 10 healthy subjects estimated the magnitude of five inspiratory resistive loads. Two subjects were shown to have a markedly reduced slope of the magnitude estimation-resistive load relationship and were suggested to be “poor perceivers” of respiratory stimuli. In Part 2, evoked potentials were recorded from the same 10 subjects using the same resistive loads as Part 1. A log-log plot of the group averaged P1 amplitudes showed a linear relationship with resistive load. Aberrant P3 components were seen in the 2 poor perceiving subjects and one of the 2 showed no late response. In the other 8 subjects, P3 varied as a function of resistive load, being augmented to larger loads. These results provide evidence that P3 may be a key index of the perception of respiratory sensitivity and effort.

We hypothesized that patterns of sympathetic and parasympathetic reactivity observed in adults would be apparent in a sample of children and adolescents and that these patterns would be consistent across tasks. We explored the relationship between these patterns and psychosocial risk factors for cardiovascular disease. We measured preejection period (PEP) and an index of respiratory sinus arrhythmia (mean successive difference [MSD] statistic) during three reactivity tasks. We classified participants into four groups based on increases or decreases in PEP and MSD. Ninety percent of the sample exhibited the same pattern during at least two of the tasks. PEP and MSD demonstrated consistency, suggesting individual response stereotypy. Exhibiting a consistent pattern of decreased PEP and increased MSD was associated with less child- and parent-reported family conflict. These results are discussed in the context of vagal regulation of environmental demands.

In this study we examined whether event-related potentials (ERPs) associated with stimulus repetition and recognition in a serial-probe recognition task were comparable to ERPs in other tasks that are more typically used to investigate old/new ERP effects. The experiment consisted of 320 trials in which a recognition probe followed a four-item memory set; 160 trials consisted of images depicting common objects that were easy to label (EL task), and 160 trials consisted of images depicting abstract patterns that were difficult to label (DL task). Nineteen participants indicated whether a probe that followed each memory set was or was not presented in the memory set. Half of the probes matched, and half did not match, an item in the preceding memory set. ERPs appeared to reflect two processes—one that differentiated between recently presented stimuli and other stimuli and another that distinguished between repeated stimuli and new stimuli. ERPs to recent probes were more positive than ERPs to other probes in the EL and DL tasks. ERPs to match (old) probes were more positive than ERPs to nonmatch (new) probes only in the EL task.

We present a new wavelet-based method for single trial analysis of transient and time variant event-related potentials (ERPs). Expecting more accurate filter settings than achieved by other techniques (low-pass filter, a posteriori Wiener filter, time invariant wavelet filter), ERPs were initially balanced in time. By simulation, better filter performance could be established for test signals contaminated with either white noise or isospectral noise. To provide an example of real application, the method was applied to limbic P300 potentials (MTL-P300). As a result, variance of single trial MTL-P300s decreased, without restricting the corresponding mean. The proposed method can be regarded as an alternative for single-trial ERP analysis.