Blood pressure presentation mode and personality are likely to influence biofeedback outcome. Thirty-six normotensive subjects were randomly assigned to visual or auditory continuous systolic feedback. “Distracting speech” and “broad band noise” were also superimposed and the effect on the biofeedback response was investigated. Psychological influence was also investigated. Systolic pressure reductions of 4 ± 4.3 mmHg (visual, p = .04) and 5 ± 5.5 mmHg (visual + auditory, p = .03) were achieved compared with auditory feedback (2 ± 4.7 mmHg), which was less effective. The addition of noise or speech had no effect on the systolic response, but speech adversely affected diastolic reduction (p = .04). Mood (p = .003) was associated with systolic lowering, whereas increased trait anxiety (p = .06) and expectation (p = .03) had trends for opposite effects. Increased anger-hostility, state-anxiety, and expectation (p = .06) had links with systolic raising capability. We conclude that feedback modality and psychological characteristics have implications for studies investigating blood pressure manipulation capability.

Two experiments were conducted to understand the influence of estrogen exposure on cardiovascular responses to acute stress measured by impedance cardiography. Study 1 compared stress responses of 29 postmenopausal women who used postmenopausal hormone replacement therapy (HRT) and 29 who did not use HRT. Women who did not use HRT had higher systolic blood pressure and pulse pressure responses to the tasks relative to HRT users. Study 2 compared stress responses of 38 healthy postmenopausal women not initially on HRT who were randomly assigned to transdermal estradiol or placebo treatment for 6–8 weeks. HRT assignment did not influence substantially women's cardiovascular responses to stress. Characteristics correlated with HRT use, not HRT itself, or differences in type, duration, and dosage may account for the discrepancy in results.

Our recent work suggests that innocuous somatosensory activity elicited by a brief electrical stimulus is inhibited by pain evoked by the same electrical stimulus but not by pain evoked by continuous heat. These results led to the hypothesis, tested in the present experiment, namely that pain only inhibits innocuous somatosensation when the painful and innocuous stimuli have short durations and close temporal and spatial overlap. A painful 200-ms laser pulse did not produce a decrease in the perceived magnitude of the innocuous electrical stimulus or in the amplitude of a scalp potential that earlier work suggested is generated by neurons involved in innocuous somatosensation. Hence, the pain-related inhibition of innocuous somatosensation observed in these electrical studies cannot be attributed solely to the duration or to the temporal and spatial overlap of the innocuous and painful stimuli. Laser pain did produce a small increase in the subjective magnitude of the innocuous electrical stimulus, which the electrophysiological evidence suggests might be due to a change in the late- but not the midlatency responses in the central innocuous somatosensory pathways.

This study investigated the influences of both perceived control and physical effort on cardiovascular reactivity. Undergraduates (N = 32) played a video game task interrupted by aversive noise. Perceived control of the noise was manipulated by instructions indicating the presence or absence of a contingency between performance and noise presentations. Physical effort was manipulated by controlling the physical force required to perform the task. There was a significant main effect of control on systolic blood pressure (SBP) and total peripheral resistance (TPR), with both increasing more during low than high control conditions. The results suggest that high perceived control over aversive noise in an effortful task reduces SBP and TPR reactivity relative to low perceived control. The results are consistent with the idea that control buffers the reactivity associated with task performance under aversive conditions.

In the current study, we examined lipid and cardiovascular responses to an acute stressor among men with and without a parental history of myocardial infarction. 37 men were selected from a large group who completed medical history questionnaires and interviews. Twenty-two men who denied parental history of heart disease (negative parental history) were compared with 15 men with one or both parents who had suffered a myocardial infarction (positive parental history). Total cholesterol, high- and low-density lipoprotein cholesterol, triglycerides, heart rate, and blood pressure were measured at rest and during a videotaped speech stressor. Positive parental history men had significantly higher low-density lipoprotein cholesterol levels and blood pressure at baseline, significantly lower high-density lipoprotein cholesterol levels at baseline, and significantly larger total cholesterol and low-density lipoprotein cholesterol reactivity, relative to negative parental history men. Because parental history is a risk factor for subsequent cardiovascular morbidity and mortality, these data suggest that lipid reactivity to stress may be biologically important.

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.

Blood pressure presentation mode and personality are likely to influence biofeedback outcome. Thirty-six normotensive subjects were randomly assigned to visual or auditory continuous systolic feedback. “Distracting speech” and “broad band noise” were also superimposed and the effect on the biofeedback response was investigated. Psychological influence was also investigated. Systolic pressure reductions of 4 ± 4.3 mmHg (visual, p = .04) and 5 ± 5.5 mmHg (visual + auditory, p = .03) were achieved compared with auditory feedback (2 ± 4.7 mmHg), which was less effective. The addition of noise or speech had no effect on the systolic response, but speech adversely affected diastolic reduction (p = .04). Mood (p = .003) was associated with systolic lowering, whereas increased trait anxiety (p = .06) and expectation (p = .03) had trends for opposite effects. Increased anger-hostility, state-anxiety, and expectation (p = .06) had links with systolic raising capability. We conclude that feedback modality and psychological characteristics have implications for studies investigating blood pressure manipulation capability.

Twenty-four 8–10-year-old children (13 very low birthweight, 11 control) performed a lexical decision and a semantic classification task while event-related potentials (ERPs) were recorded. Both groups were within normal range on standardized reading tests, but the very-low-birthweight group had lower scores. There were no differences between groups in reaction times or accuracy for ERP tasks. On analyses of P2a (246 ms anteriorly), P2p (336 ms posteriorly), N2a (356 ms anteriorly), and N2p (396 ms posteriorly) peaks and a late positive component, control children showed greater right than left asymmetry at P2p and greater left than right asymmetry at N2a. Very-low-birthweight children showed less asymmetry. For the late positive component, both groups showed greater left than right asymmetry, which was more marked for the semantic classification task. The results suggest that very-low-birthweight children display differing cortical utilization during reading.

Increased frequency of anticipatory saccades during smooth pursuit eye movements is a potential marker of genetic risk for schizophrenia. Postsaccadic slowing criteria are used to separate anticipatory from other types of saccades. However, the necessary duration of slowed pursuit required to identify an anticipatory saccade remains undetermined. We explored the effect of various postsaccadic slowing duration criteria on effect size in a comparison of younger and older schizophrenic and normal adults. For large anticipatory saccades, varying the duration of postsaccadic slowing criteria did not notably change effect size. For smaller leading saccades, a limited 50-ms duration postsaccadic slowing criterion produced the largest effect size (1.54), and maintained a similar effect size across a broad age range. Leading saccades with a limited duration postsaccadic slowing criteria are a possible marker of genetic risk for schizophrenia.

Performance and event-related potentials (ERPs) were examined in a proactive interference (PI) task with 15 male schizophrenic patients and 15 matched healthy controls. Within a paired-associate task, 30 pairs of semantically unrelated words (A-B) were presented twice, followed by cued recall, in which the paired-associate B had to be named upon cue A. Subsequently, 50% of the A-words were paired with new words (A-C) and presented in random order together with 15 novel pairings (D-E). Slower responses and poorer recall of C- than of E-words in the final recall indicated PI in both groups. During acquisition, the paired-associates (C/E) evoked larger P3 and positive slow wave in controls than in patients. During recall, cues (A/D) evoked a slow wave with predominating anterior negativity in controls and posterior positivity in patients. The group-specific ERP pattern suggests deviant encoding and retrieval processes in schizophrenic individuals.

The effect of visual stimulus significance on saccade latency and accuracy in gaze shifts was investigated. Stimulus significance refers to the temporal proximity of an imperative stimulus. It was hypothesized that stimulus significance serves as a cue that influences the observer's expectancy for a forthcoming event. Twenty-one undergraduate students participated in two experiments involving monitoring of visual events. Stimuli were a sequence of 1,000 single-digit integers presented one at a time at 9° of visual angle to the left or right of a fixation point in random order. The subject was required to make a manual response after the presentation of a sequence of two odd integers. The probability of the subsequent integer being odd, a “target,” after the presentation of an odd integer was 0.75. The integer after a target was always an even integer. When stimulus location was unpredictable (Experiment 1), latency of visually guided saccades to the target was shorter (p < .01) than to the nontarget stimuli. Under the condition of predictable stimulus location (Experiment 2), anticipatory saccades to the target occurred earlier (p < .01), more frequently (p < .01), and more accurately (p < .05). Our results suggest that both timing and accuracy of gaze shift are affected by the observer's expectation of future events.

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.

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.

This study examined the effects of visual selective attention and stimulus discriminability on phasic heart rate changes. Grating stimuli consisting of four vertical bars were presented left or right from fixation. Participants attended to one side of the screen and responded with a button press to attended target stimuli that were defined by shorter middle bars. Stimulus discriminability was manipulated by increasing the length of the middle bars of targets. To examine the time course of response inhibition, participants had to respond to auditory probe stimuli that were presented occasionally and unpredictably at varying intervals following the visual stimulus. Responses to targets and probes following attended nontargets were slower in the difficult condition. Heart rate slowed in anticipation of a target and accelerated back to baseline afterwards. Phase-dependent cardiac slowing was larger for attended nontargets compared to unattended nontargets and was more pronounced in the difficult condition. These findings were interpreted vis-à-vis inhibition accounts of phase-dependent cardiac slowing.

Two human Pavlovian conditioning experiments investigated the impact of reinforcement density (the number of reinforced trials divided by the total number of trials) on discrimination learning. Experiment 1 used a negative patterning problem (A+, B+, AB−) and Experiment 2 used a positive patterning problem (A−, B−, AB+). In both experiments, reinforcement density varied across four levels. Response differentiation between reinforced and nonreinforced stimuli was linearly related to the decrease in reinforcement density. Responses to nonreinforced stimuli did not differ between the four groups in either experiment. In contrast to this, responses to reinforced stimuli were considerably more pronounced in conditions with lower reinforcement density. For negative patterning, this replicates and extends similar observations from other species. For positive patterning, this is a finding that has not yet been reported in other experiments. The results are in agreement with the comparator hypothesis (Miller & Matzel, 1988) and with Wagner's (1981) “standard operating procedures” (SOP) model.

In 1960, the newly founded Society for Psychophysiological Research captured the already considerable breadth of the just-forming field of psychophysiology. The Society began publishing Psychophysiology in 1964 with the mandate to address that breadth. As the field has grown rather enormously in the past 40 years, the journal has expanded accordingly. Whole new (and still overlapping) fields such as behavioral medicine have taken root, and new technologies such as hemodynamic brain imaging continue to enrich the psychophysiologist's toolbox. Beyond important domains of clinical, developmental, and human-factors application and exciting methodological developments, psychophysiology has made great progress on basic substantive questions such as the relationship of fundamental reflexes to emotional behavior and the role of regional brain specialization in perceptual and cognitive function. In so doing, the field has necessarily faced up to conceptual challenges such as what is involved in manipulating emotion in the laboratory and in verifying the manipulation.

In two experiments, we explored the utility of using event-related brain potentials (ERPs) evoked during picture recognition to examine the cognitive and neural processes underlying primacy and recency effects. Each experiment consisted of 210 trials in which a recognition probe followed a 12-picture sequence (105 match and 105 nonmatch trials). The 105 match-probe trials consisted of 35 trials in which the probe matched a prime memory set item (Positions 1–3), 35 in which the probe matched a middle memory set item (Positions 6–8), and 35 in which the probe matched a recent memory set item (Positions 10–12). Behavioral results revealed recency but not primacy effects in both experiments. Recent probes, compared with prime and middle probes, evoked ERPs that were more positive from approximately 300 to 400 ms; this enhanced positivity occurred in a positive component peaking around 315 ms and a negative component peaking around 365 ms. These findings fit more closely with the notion of short-term memory as an activation of elements in long-term memory than as a distinct memory store (or stores) separate from long-term memory.

Presentation to John Cacioppo on the occasion of the Award for Distinguished Contributions to Psychophysiology, Saturday October 21, 2000, San Diego.

AC amplifiers can introduce significant distortions into the low frequency and DC components of recorded electrophysiological data such as event-related potentials (ERPs). Methods for correcting such distortions (i.e., estimating the waveform of the original data) after the data have been amplified and recorded rely on an accurate estimate of the amplifier's time constant (TC). We show that the filter characteristics of AC amplifiers in at least some commercially available ERP recording instruments may vary considerably across individual channels, even when each houses an identical AC amplifier circuit. Clearly, distortion correction methods must take this variability into account. We propose an empirical means of estimating the correct TC value. This approach yields more accurate correction than those based on TCs calculated analytically.

Arterialized and venous blood was compared to determine if the arterialization procedure enhances the detection of stress-related changes in catecholamines. Lipid and hematologic measures were also compared for possible distortion by arterialization. Fifteen men completed two stressors. Indwelling venous catheters were placed retrograde in each hand, and the right hand was warmed to a constant temperature. Blood samples were taken simultaneously from both hands, and plasma catecholamines were determined. Arterialization increased baseline epinephrine; there were no effects of arterialization on catecholamines during stress, nor in lipid or hematologic measures during baseline or stress. Thus, arterialization of blood results in small increases in resting epinephrine levels, but does not obscure lipid measures. More importantly, arterialization of venous blood does not enhance the detection of stress-related changes in catecholamines.