Because it is difficult to distinguish differences in event-related potentials between psychopaths and nonpsychopaths in Figures 1, 2, and 3, replacement figures are available upon request from the corresponding authors, Kent A. Kiehl or Robert D. Hare, 2136 West Mall, Department of Psychology, University of British Columbia, Vancouver, B.C., Canada, V6T 1Z4. E-mail KAK kiehl@cs.ubc.ca, RDH rhare@unixg.ubc.ca.

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.

Electrooculogram (EOG) correction is used to remove eye-movement-related contamination from electroencephalograms (EEG). Correction is reliant on the regression procedure, although when multiple EOG channels are used in the correction, the appropriate type of regression to use is not known. In the present study, we aimed to resolve this matter. Computer simulations were used to compare the simultaneous, multiple-stage, and single-channel regression methods of correction. EOG propagation was modeled on prior findings, under conditions of varying vertical and horizontal EOG (VEOG/HEOG) correlation. The dependent variable was the correlation between the uncontaminated and the corrected EEG. The simultaneous regression procedure gave the best correction, with its advantage increasing as a function of VEOG/HEOG correlation. It is recommended that the simultaneous regression procedure be used for EOG correction of the EEG.

Studies examining the association between laboratory measures of stress-related cardiovascular (CV) reactivity and responses to psychological challenges in the natural environment have yielded mixed results. Frequently, single laboratory tasks have been used to predict responses to natural stressors on a single occasion of measurement. Because aggregation broadens the range of stimuli sampled and reduces measurement error, laboratory-to-life generalizability should be more easily detected when multiple predictor and criterion observations are used. Sixty students in a public speaking course were administered multitask assessments of CV reactivity during two laboratory sessions and during two in-class public speech assignments. CV responses to the classroom speeches were greater among those who showed larger responses in the laboratory, and these associations became stronger as measures were aggregated across multiple samples of behavior. These results support the generalizability of CV reactivity as a measure of individual difference, and they help to shed light on previous inconsistent findings in this area.

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.

Attentional and information processing impairments have been evidenced in nonclinical anhedonic subjects. However, the extent of attentional deficit has not been determined. We studied focused attention, the ability to reject irrelevant or distracting messages, in anhedonic nonclinical subjects. The event-related potentials and behavioral performances of anhedonic subjects were compared with those of control subjects during the Eriksen focused attention task (C.W. Eriksen & B.A. Eriksen, 1974); the task combined one compatible and one incompatible condition, the latter causing an interference. Anhedonic subjects exhibited a smaller P300 and slower reaction times than control subjects. Varying task conditions had different effects on anhedonic subjects and controls, suggesting that anhedonic subjects may have developed a conservative response strategy. In view of previous works, these results suggest that attentional impairment is not ascribed to specific processes, but may involve a more global deficit, that is, a resource allocation deficit.

The underuse of cardiovascular recovery as an adjunct to reactivity may stem from a lack of research on how to assess the process reliably. We explore the test–retest reliability of three simple, intuitive approaches to measuring recovery, and of a more sophisticated curve-fitting technique. Eighteen young normotensive subjects experienced three stressors twice each, with 10-min baseline, 3-min task, and 20-min recovery periods and continuous monitoring of heart rate and blood pressure. Reactivity showed moderate reliability, but the three simple approaches to measuring recovery revealed essentially none. However, the curve-fitting approach, using a three-parameter (amount, speed, and level of recovery) logistic function was reliable. This approach, capturing the inherently dynamic process of cardiovascular recovery, may allow researchers to usefully add the assessment of recovery to paradigms exploring reactivity as a risk factor for cardiovascular disease.

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.

Event-related potentials (ERPs) were recorded during recognition tasks for line drawings (items) or for both drawings and their spatial locations (sources). Recognized drawings elicited more positive ERPs than new drawings. Independent of accuracy in the spatial judgment, the old/new effect in the source recognition task was larger over the prefrontal scalp, and of longer temporal duration than in the item recognition task, suggesting that the source memory task engaged a qualitatively distinct memory process. More posterior scalp sites were sensitive to the accuracy of the source judgment, but this effect was delayed relative to the difference between studied and unstudied drawings, suggesting that source memory processes are completed after item recognition. Similarities and differences between spatial source memory and memory for conjunctions of other stimulus attributes are discussed, together with the role of prefrontal cortex in memory.