Perpetrators of domestic violence describe symptoms that are compatible with exaggerated autonomic arousal at the time of the domestic violence. This inappropriate arousal may be reflected in altered heart rate regulation. If heart rate is systematically regulated by vagal mechanisms, then increases in heart rate should correlate with decreases in cardiac vagal activity, as indexed by respiratory sinus arrhythmia (RSA). We hypothesized that perpetrators of domestic violence have an alteration in heart rate regulation. To test this hypothesis we compared the results of a postural shift performed on perpetrators, healthy volunteers, and nonviolent alcoholics. Results showed there were no significant differences in heart rate, RSA, or catecholamines. However, the significant inverse relationship between posture-elicited changes in RSA and heart rate present in the healthy volunteers was not found in perpetrators. These differences in the covariation between heart rate and RSA may represent differences in the neural regulation of heart rate and may be related to difficulties in controlling autonomic state.

Test–retest stability of electrodermal (EDA) variables indexing both general autonomic arousal (e.g., skin conductance level, number of nonspecific skin conductance responses) and attention to external stimuli (e.g., number of skin conductance orienting responses, electrodermal responder/nonresponder status) was assessed in 71 young, recent-onset schizophrenia patients and 36 demographically matched normal subjects. Significant stability over a 1-year period was found for both patients and normal subjects for most EDA variables and for responder/nonresponder status, with test–retest correlations generally being higher for normal subjects. The lower reliability for patients was not attributable to symptomatic fluctuations during the follow-up period and may reflect poorer arousal regulation among the patients. Among measures of responding to nontask stimuli, a simple count of the number of orienting responses occurring was more stable than was a traditional trials-to-habituation measure.

To examine changes in semantic memory organization and use during aging, we recorded event-related potentials as younger and older adults listened to sentences ending with the expected word, an unexpected word from the same semantic category, or an unexpected word from a different category. Half of the contexts were highly constraining. In both groups, expected words elicited less negativity 300–500 ms (N400) than unexpected ones, and unexpected words elicited smaller N400s when these were categorically related. Whereas younger adults showed the greatest N400 reduction to unexpected but related words in high constraint contexts, older adults showed the opposite tendency. Thus, unlike younger adults, older adults as a group do not seem to be using context predictively. Older adults with higher verbal fluency and larger vocabularies, however, showed the younger response pattern, suggesting resource availability may offset certain age-related changes.

Norepinephrine is believed to modulate CNS processing of environmental signals. However, its specific role in stimulus evaluation processes has not been delineated. We examined the effects of the α2 noradrenergic agents, clonidine and yohimbine, on ERP and performance measures of auditory information processing. Ten healthy participants performed a three-tone target detection experiment, receiving either placebo, 0.2 mg clonidine, or 30 mg yohimbine, in a double-blind randomized design. The principal locus of action of the noradrenergic agents occurred between 100 and 200 ms poststimulus. P200 latency was sped by yohimbine and slowed by clonidine, and the frontal P3a was shifted in tandem. Components related to target detection (N250 and P3b) were unaffected. The results suggest that norepinephrine modulates CNS mechanisms of selective attention to infrequent stimuli. This may be relevant for patients with schizophrenia, a subset of whom exhibit selective abnormalities of these same ERP components. Our results offer a possible link between these two sets of findings, suggesting that some patients with schizophrenia may have dysfunctional noradrenergic systems.

Previous studies have suggested that the memory underlying the mismatch negativity (MMN) can be deactivated by a period of silence and later reactivated. An alternative is that the memory becomes inapplicable due to a period of silence and subsequently reinstated. Both interpretations rest on the absence of a MMN for a deviant in Position 1 of a train (showing deactivation or inapplicability of the memory) and the presence of a MMN in Position 2 of the train (evidencing reactivation or reinstatement of the memory). In these studies, the standards were fixed across all trains of a given condition. Hence, it is not clear if the MMN elicited in Position 2 requires presentation of multiple trains with identical standards or only a single train. Experiment 1 showed that a single train is sufficient. With data from recent studies, Experiment 2 showed that MMNs in Position 2 of trains are due to reinstatement rather than reactivation of the memory.

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.

Accurate and early diagnosis of Alzheimer's Disease (AD) with reliable and noninvasive methods is of great importance for clinical practice as effective and specific antidementive therapies become available. The aim of the study was to evaluate the clinical relevance of event-related P300 in the early diagnosis of AD. Thirty patients with AD, 26 patients with mild cognitive impairment (MCI) from our Memory Clinic and 26 age-matched healthy controls (HC) were studied with event-related P300 potentials. Amplitudes of temporo-basal dipoles (TB-P300) were significantly diminished in AD compared to HC and MCI. Furthermore, latencies of temporo-superior dipoles (TS-P300) were significantly prolonged in AD compared with HC. Sensitivity was 90.0% for the differentiation of patients with AD from HC (specificity 79.1%) using reduced TB-P300 amplitudes and prolonged TS-P300 latencies. Similar results were found using Pz amplitudes as well as Fz latencies. Our data suggest that TB-P300 amplitudes and TS-P300 latencies may be an accurate clinically available, nonexpensive, noninvasive, and reliable marker for AD.

This study examined cardiovascular effects of energy resource depletion. Participants first made a series of easy or difficult grips with their right or left hand. They then made and held a moderately difficult dynamometer grip with their right hand while measures of blood pressure and heart rate were taken. As expected, systolic blood pressure responses during the second task period were greater when the first task was difficult than when it was easy if the first task was performed with the right hand, but not if the first task was performed with the left hand. The data support the view that ability perception and, thus, cardiovascular responsiveness vary with relevant energy stores.

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.

Error trials are associated with faster responses than correct trials in simple discrimination tasks suggesting that errors result from impulsive responding. We investigated the relationship between error negativity (Ne/ERN), an event-related potential associated with error detection, and two behavioral indices of response control: response time (RT) differences between incorrect and correct trials (an index of impulsivity) and percentage of errors. Response-locked ERPs were collected from 17 young adults during a visual flanker task. Consistent with previous findings, participants were significantly faster on error trials. However, participants who exhibited larger Ne/ERN peak amplitudes had significantly smaller RT differences, suggesting a more controlled response strategy. Furthermore, Ne/ERN latencies were positively associated with percentage of errors. These findings are consistent with the view that the Ne/ERN reflects the activity of a monitoring system that is closely linked to remedial systems responsible for individual differences in response control or impulsive behavior.

The present study was aimed at deciphering whether the delay in choice reaction time (RT) and the silent period (SP) caused by transcranial magnetic stimulation (TMS) of the motor cortex in the ongoing electromyogram are due to the same physiological mechanism. To this end, the effect of TMS was studied in 6 healthy volunteers performing a between-hand choice RT task. Specific predictions were derived from a logic inspired from the “postponed stages” hypothesis (Pashler & Johnson, 1989). This logic predicts a correlation between SP duration and RT when the stimulated cortex is involved in the response, and a stronger correlation when the stimulation is delivered later during the RT interval. The effect of TMS on RT was twofold: At early stimulation times, the stimulation shortened the RT and this effect was independent of the involvement of the stimulated motor cortex in the subsequent response. At later stimulation times, TMS had a disruptive effect, provided that the stimulated cortex was involved in the response. When the stimulated cortex was involved in the response, there was a correlation between SP and RT; this correlation was stronger when the stimulation occurred later. In contrast, there was no correlation between these two variables when the stimulated cortex was not involved.

The present study evaluated the ability of a weak electrical prepulse to modify startle caused by a more intense shock. Painful electrical shocks (150 V, 0.5 ms duration) were presented to the upper arm of college student participants, preceded on some trials by a weaker shock (0.5 ms duration, at perceptual threshold) at the same location. Intense shocks elicited eyeblink reflexes, and these eyeblinks were inhibited by weak electrical prepulses. These data suggest that the inclusion of prepulses immediately preceding painful therapeutic shocks, such as those generated by an implanted cardioverter-defibrillator, might be capable of reducing the startle response generated by that therapeutic shock.

To examine gender differences in immune reactions to stress and relationships between immune and cardiovascular reactivity, measures of cellular and mucosal immunity and cardiovascular activity were recorded in 77 men and 78 women at rest and in response to active (mental arithmetic) and passive (cold pressor) stress tasks. Both tasks reduced CD4+ T cells and the CD4/8 ratio. Total lymphocytes, NK cells, CD8+ T cells, and secretory immunoglobulin A (sIgA) increased with active stress. Passive stress decreased sIgA. At rest, men had more NK cells, less CD4+ T cells, and fewer neutrophils than women. Mental stress increased sIgA in men but not women. Cardiovascular reactivity to active stress was associated with increases in NK cells. The data support the hypothesis that stress-related increases in lymphocytes are beta-adrenergically mediated, and suggest that the fall in CD4+ T cells may be alpha-adrenergically driven. Mechanisms underlying sIgA reactions are more difficult to determine. Men and women differed in some cell counts, but not in reactivity, although gender influenced sIgA reactions to arithmetic.

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.

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.

Two experiments compared finger plethysmograph (FP) to electrocardiogram (ECG) in providing accurate heart periods for use in heart rate variability (HRV) calculations. In Experiment 1, simultaneous ECG and FP recordings were taken from 16 healthy subjects at rest. In Experiment 2, 10 additional healthy subjects were recorded at rest and during the Stroop Color-Word Test. In both studies, high correlations were found between FP-derived and ECG-derived band variance for high and low frequency HRV at rest. But, during the Stroop task, correlations were strongly diminished. In addition, under both conditions, HRV measures were significantly higher using the FP signal. Thus, FP may be adequate for determining HRV at rest, but, for experimental use, ECG may still be recommended. Nonetheless, further studies that include test–retest reliability assessment of both data collection techniques are warranted before a more certain determination can be made.

The present study was undertaken to determine whether aversiveness contributes to startle potentiation in anticipation of affective pictures above and beyond the effects of emotional arousal. Further, participants high in trait anxious apprehension, which is characterized by worry about the future, were expected to show especially pronounced anticipatory startle responses. Startle blink reflex was measured during warning stimuli that predicted the valence of ensuing aversive/unpleasant, pleasant, or neutral pictures. Startle magnitude was larger in anticipation of aversive than of pleasant pictures and smallest in anticipation of neutral pictures. Enhanced startle potentiation was not found in anxious apprehension subjects. These data suggest that the aversive nature of stimuli contribute to the potentiation of startle above and beyond the effects of emotional arousal, which may be a universal phenomenon not modulated by individual differences.