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Deception often occurs in response to a preceding cue (e.g., a precarious question) alerting us about the need to subsequently lie. Here, we simulate this process by adapting a previously established paradigm of intentionally false responding, now instructing participants about the need for deception (vs. truthful responses) by means of a simple cue occurring before each response‐relevant target. We analyzed event‐related brain potentials (ERPs) as well as cortical oscillations recorded from the scalp. In an experimental study (N = 44), we show that a cue signaling the need for deception involves increased attentional selection (P2, P3a, P3b). Moreover, in the period following the cue and leading up to the target, ERP and oscillatory signatures of anticipation and preparation (Contingent Negative Variation, alpha suppression) were found to be increased during trials requiring a deceptive as compared to a truthful response. Additionally, we replicated earlier findings that target processing involves enhanced motivated attention toward words requiring a deceptive response (LPC). Moreover, a signature of integration effort and semantic inhibition (N400) was observed to be larger for words to which responses have to be intentionally false as compared to those to which responses must be truthful. Our findings support the view of the involvement of a series of basic cognitive processes (especially attention and cognitive control) when responses are deliberately wrong instead of right. Moreover, preceding cues signaling the subsequent need for lying already elicit attentional and preparatory mechanisms facilitating the cognitive operations necessary for later successful lying. [ABSTRACT FROM AUTHOR]

In some situations, for example, when we expect to gain a reward in case of good performance, goal‐driven top‐down attention is particularly strong. Little is known about the task specificity of such increases of top‐down attention due to environmental factors. To understand to what extent performance‐contingent reward prospects can result in specific and unspecific changes in cognitive processing, we here investigate reward effects under different levels of task specification. Thirty‐two participants performed a visual or an auditory discrimination task cued by two consecutive visual stimuli: First, a reward cue indicated if good performance was rewarded. Second, a task cue announced either which of the two tasks would follow (precise cue) or that both tasks would follow equally likely (imprecise cue). Reward and task cue preciseness both significantly improved performance. Moreover, the response time difference between precisely and imprecisely cued trials was significantly stronger in rewarded than in unrewarded trials. These effects were reflected in event‐related potential (ERP) slow wave amplitudes: Reward and preciseness both significantly enhanced the contingent negative variation (CNV) prior to the task stimulus. In an early CNV time interval, both factors also showed an interaction. A negative slow wave prior to the task cue was also significantly enhanced for rewarded trials. This effect correlated with the reward difference in response times. These results indicate that reward prospects trigger task‐specific changes in preparatory top‐down attention which can flexibly adapt over time and across different task requirements. This highlights that a reward‐induced increase of cognitive control can occur on different specificity levels. [ABSTRACT FROM AUTHOR]

Accurate time perception is a crucial element in a wide range of cognitive tasks, including decision‐making, memory, and motor control. One commonly observed phenomenon is that when given a range of time intervals to consider, people's estimates often cluster around the midpoint of those intervals. Previous studies have suggested that the range of these intervals can also influence our judgments, but the neural mechanisms behind this "range effect" are not yet understood. We used both behavioral tests and electroencephalographic (EEG) measures to understand how the range of sample time intervals affects the accuracy of people's subsequent time estimates. Study participants were exposed to two different setups: In the "blocked‐range" (BR) session, short and long intervals were presented in separate blocks, whereas in the "interleaved‐range" (IR) session, intervals of various lengths were presented randomly. Our findings indicated that the BR context led to more accurate time estimates compared to the IR context. In terms of EEG data, the BR context resulted in quicker buildup of contingent negative variation (CNV), which also reached higher amplitude levels and dissolved more rapidly during the encoding stage. We also observed an enhanced amplitude in the offset P2 component of the EEG signal. Overall, our results suggest that the variability in time intervals, as defined by their range, influences the neural processes that underlie time estimation. Our study elucidates the neural underpinnings of the sample distribution range effect in temporal reproduction. The EEG data reveal that all timing‐related components (CNV, P2, and LPCt) are sensitive to the target duration, whereas only CNV and P2 are modulated by the range effect. This possibly shows higher anticipation and prior precision in the narrow‐range context. [ABSTRACT FROM AUTHOR]

The current registered report focused on the temporal dynamics of the relationship between expectancy and attention toward threat, to better understand the mechanisms underlying the prioritization of threat detection over expectancy. In the current event‐related potentials experiment, a‐priori expectancy was manipulated, and attention bias was measured, using a well‐validated paradigm. A visual search array was presented, with one of two targets: spiders (threatening) or birds (neutral). A verbal cue stating the likelihood of encountering a target preceded the array, creating congruent and incongruent trials. Following cue presentation, preparatory processes were examined using the contingent negative variation (CNV) component. Following target presentation, two components were measured: early posterior negativity (EPN) and late positive potential (LPP), reflecting early and late stages of natural selective attention toward emotional stimuli, respectively. Behaviorally, spiders were found faster than birds, and congruency effects emerged for both targets. For the CNV, a non‐significant trend of more negative amplitudes following spider cues emerged. As expected, EPN and LPP amplitudes were larger for spider targets compared to bird targets. Data‐driven, exploratory, topographical analyses revealed different patterns of activation for bird cues compared to spider cues. Furthermore, 400–500 ms post‐target, a congruency effect was revealed only for bird targets. Together, these results demonstrate that while expectancy for spider appearance is evident in differential neural preparation, the actual appearance of spider target overrides this expectancy effect and only in later stages of processing does the cueing effect come again into play. This study examined online expectancy and subsequent emotional attention to threat at early as well as late processing stages using event‐related potentials and topographical analyses. This comprehensive study can facilitate the development of better treatments aimed at reducing attention bias and anxiety/phobia symptoms by focusing on the manipulation of expectancies. [ABSTRACT FROM AUTHOR]

The amount of cognitive and neural resources allocated to a task is largely determined by the reward we can expect. However, it remains under‐appreciated how this reward‐expectation‐based control allocation is modulated by effort expenditure. The present event‐related potential study investigated this issue through the lens of neural dynamics. Thirty‐four participants completed an effort‐based monetary incentive delay task while their EEG was recorded. Effort demand was manipulated by adding no (low effort) or much (high effort) noise to the target. Behaviorally, participants exhibited reward‐related speeding regardless of effort expenditure, as revealed by faster RTs for reward than neutral trials. Our ERP results demonstrated a widespread facilitatory influence of reward expectation on neural dynamics extending from cue evaluation as indexed by the cue‐P3, to control preparation as indexed by the contingent negative variation (CNV), and finally to control engagement as indexed by the target‐P3. Critically, the neural facilitation was discounted by effort expenditure during both the control‐preparation and control‐engagement stages instead of the cue‐evaluation stage. Overall, this study provides neurodynamic evidence that control allocation is determined by reward and effort via a cost–benefit analysis. We examine how reward‐expectation‐based control allocation is modulated by effort expenditure through the lens of neural dynamics. We provide evidence that control allocation is facilitated by reward prospects on the CNV and target‐P3, which is further discounted by effort expenditure. Our results highlight that control allocation is determined by reward and effort via a cost–benefit analysis. [ABSTRACT FROM AUTHOR]

In response time (RT) research, RTs which largely deviate from the RT distribution are considered "outliers". Outliers are typically excluded from RT analysis building upon the implicit assumption that cognitive processing is distorted in outlier trials. The present study aims to test this assumption by comparing cognitive processing indexed by event‐related potentials (ERP) of trials with outliers and valid trials in two different tasks. To this end, we compared stimulus‐ and response‐locked ERPs for outliers identified by nine different methods with valid trials, using cluster‐based permutation tests. Consistently across outlier exclusion methods and tasks, the late positive complex (P3) associated with response‐related processes was reduced in outliers. Analyses of response‐locked ERPs related this P3 attenuation to a slower and temporally more extended increase of the P3, possibly indexing reduced evidence accumulation speed in outliers. P3 peak amplitude in response‐locked ERPs was similar between outliers and valid trials, suggesting that the absolute amount of evidence required for a response remained comparable. Furthermore, in addition to these more general ERP correlates of outliers, the contingent negative variation (CNV) ERP component was reduced in outliers as a function of preparatory demands of the task. Hence, electrophysiological correlates, and thus cognitive processing, are altered in outliers compared to valid trials. In order to avoid distortion of observed ERP differences between conditions, the RT outlier distribution should be considered for the analysis of ERPs in combined ERP and RT studies. Many studies in experimental psychology incorporate the assessment of response times (RT). For statistical analysis, RT outliers are typically excluded, as they are implicitly assumed to not represent the cognitive processes intended to be studied. The present study aims to test this assumption by comparing event‐related potentials (ERP) between outliers and valid trials. The results showed that ERPs differ between outlier and valid trials, supporting accounts assuming a distorted processing in outliers. [ABSTRACT FROM AUTHOR]

The C1 ERP component reflects the earliest visual processing in V1. However, it remains debated whether attentional load can influence it or not. We conducted two EEG experiments to investigate the effect of attentional load on the C1. Task difficulty was manipulated at fixation using an oddball detection task that was either easy (low load) or difficult (high load), while the distractor was presented in the upper visual field (UVF) to score the C1. In Experiment 1, we used a block design and the stimulus onset asynchrony (SOA) between the central stimulus and the peripheral distractor was either short or long. In Experiment 2, task difficulty was manipulated on a trial‐by‐trial basis using a visual cue, and the peripheral distractor was presented either before or after the central stimulus. The results showed that the C1 was larger in the high compared to the low load condition irrespective of SOA in Experiment 1. In Experiment 2, no significant load modulation of the C1 was observed. However, we found that the contingent negative variation (CNV) was larger in the low compared to the high load condition. Moreover, the C1 was larger when the peripheral distractor was presented after than before the central stimulus. Combined together, these results suggest that different top‐down control processes can influence the initial feedforward stage of visual processing in V1 captured by the C1 ERP component. Our new ERP findings inform about top‐down modulatory effects created by attentional load on early visual processing in the primary visual cortex (V1). In two experiments, we found that V1 activity was not reduced when attentional load increased. However, this lack of modulation could be explained by the likely contribution of other cognitive processes, including working memory, which could mask or interfere with the early gating of sensory processing in V1 created by attentional load. [ABSTRACT FROM AUTHOR]

Previous studies have established that effort can either decrease reward value as a cost or increase reward value as an augmenter, which is referred to as the effort paradox. The present event‐related potential study investigated the neural dynamics underlying the modulation of reward processing by effort expenditure. Thirty‐two participants completed a modified monetary incentive delay task in a high‐effort context and a low‐effort context to earn monetary rewards while their EEG was recorded during effort anticipation, effort execution, and effort completion, respectively. Results revealed the multiphase nature of the effort–reward relationship, which unfolds over time. During effort anticipation, effort discounts reward value as reflected by a reduced contingent negative variation for high‐ versus low‐effort trials. During effort exertion, the target‐P3 reward effect was accrued by effort expenditure. Finally, effort also provides its own value following effort completion, as revealed by an enhanced stimulus‐preceding negativity for high‐effort relative to low‐effort trials. These findings provide new insights into the relationship between effort expenditure and reward processing and are helpful to mitigate the effort paradox. Our findings add a new perspective on the effort–reward relationship in terms of neural dynamics. We provide evidence that effort discounts reward value during effort anticipation but enhances reward value during effort exertion and provides its own value following effort completion. Our results demonstrate a multiphase model of the effort paradox. [ABSTRACT FROM AUTHOR]

Motor learning is associated with a decrease in frontal control-related brain activity and increase of central and parietal motor-related activity. Contextual interference (CI), manipulated typically by blocked versus randomized training schedules, affects motor learning, resulting in inferior performance during training but in superior performance during retention and transfer. The CI effect is often explained by increased processing demands under high CI training. Consistently, in the motor preparation phase, the activity of control- and attention-related brain areas is increased under high CI. Here, we investigated the effect of CI on learning-related changes in ERPs during motor preparation. Participants learned throwing at virtual targets and were tested for retention in the target condition 1 week later. The frontal P3 component decreased with learning during the first session and across sessions. In addition, there was a trend for a stronger reduction of P3 during retention after high CI training. Both initial and late contingent negative variation (iCNV and lCNV) amplitudes decreased with learning and showed a significantly stronger reduction under high CI. We conclude that CI modulates the interplay of cognitive and motor processes in the preparatory phase of motor learning and that a stronger involvement of cognitive processes during high CI training accounts for differential effects of CI on ERP indicators of motor preparation during retention. [ABSTRACT FROM AUTHOR]

The present study investigated how components of ERPs are modulated when participants optimize speed versus accuracy in a cued go/no-go task. Using a crossover design, 35 participants received instructions to complete the task prioritizing response speed in half of the task, and accurate responding in the other half of the task. Analysis was performed on the contingent negative variation (CNV), P3go, and P3no-go and the corresponding independent components (IC), as identified by group independent component analysis. After speed instructions, the IC CNVlate, P3goanterior, P3no-goearly, and P3no-golate all had larger amplitudes than after accuracy instructions. Furthermore, both the IC P3goposterior and IC P3goanterior had shorter latencies after speed than after accuracy instructions. The results demonstrate that components derived from the CNV and P3 components are facilitated when participants optimize response speed. These findings indicate that these ERP components reflect executive processes enabling adjustment of behavior to changing demands. [ABSTRACT FROM AUTHOR]

The present study used ERPs to test the extent to which temporal processing is modality specific or modality general. Participants were presented with auditory and visual temporal patterns that consisted of initial two- or three-event beginning patterns. This delineated a constant standard time interval, followed by a two-event ending pattern delineating a variable test interval. Participants judged whether they perceived the pattern as a whole to be speeding up or slowing down. The contingent negative variation (CNV), a negative potential reflecting temporal expectancy, showed a larger amplitude for the auditory modality compared to the visual modality but a high degree of similarity in scalp voltage patterns across modalities, suggesting that the CNV arises from modality-general processes. A late, memory-dependent positive component (P3) also showed similar patterns across modalities. [ABSTRACT FROM AUTHOR]

Unexpected novel sounds can capture our attention and impair performance. Recent behavioral research revealed that only novel sounds that provided target-related (but not task-related) information impaired performance. This poses the question of the automaticity of novelty processing and its expression at the behavioral level. In an auditory-visual oddball paradigm, the informational content of sounds regarding the time and probability of target occurrence was varied. Independent from the informational content, novel, and deviant sounds elicited the P3a, an ERP-component related to novelty processing. In contrast, impaired performance was only observed if target-related information was provided. Results indicate that distractor sounds are automatically evaluated as potentially significant, but that the consequences for behavior depend on further processes such as the processing of the given information. [ABSTRACT FROM AUTHOR]

The study investigated interactions between autonomic cardiovascular regulation and cortical activity. In 54 healthy subjects, baroreflex sensitivity ( BRS) and respiratory sinus arrhythmia ( RSA) were assessed at resting conditions. As an EEG indicator of cortical excitability, the contingent negative variation ( CNV) was induced using a constant foreperiod reaction time task. At bivariate level, only RSA showed a moderate positive correlation with the CNV recorded at frontal electrodes. However, when common variance of BRS and RSA was controlled for in multiple regression analysis, an inverse association between BRS and the frontal CNV also arose. The inverse association between BRS and the CNV is discussed as reflecting bottom-up modulation of cortical excitability by baroreceptor afferents. The positive correlation between RSA and the CNV may relate to the interplay between prefrontal processing and cardiac vagal tone. [ABSTRACT FROM AUTHOR]

We investigated whether prior probability (PP) information modulates preparatory processes at a central premotor level or at a peripheral motor level. We provided parametrically graded probability information during the foreperiod of a precuing paradigm. The Contingent Negative Variation (CNV) and the Lateralized Readiness Potential (LRP) were used as indicators for premotor and motor preparation during the foreperiod, respectively. The CNV amplitude was parametrically modulated by PP. In contrast, the LRP amplitude during the foreperiod differed from baseline only when the precue was reliable. The interval between precue and LRP onset was shortened when probability information was delivered in contrast to noninformative advance information. Furthermore, a source analysis for the foreperiod revealed a dipole in the anterior cingulate cortex. Together, our results suggest that PP modulates preparatory processes at a central premotor level. [ABSTRACT FROM AUTHOR]

During the CNV recorded in a simple auditory working memory task, task-specific decrease of the relative delta band and a transient increase of the absolute theta band were seen, accompanied by an increase of the absolute alpha1 and alpha2 bands in the posterior region. The decreased delta power probably corresponds to increased task-evoked arousal, whereas the transient theta power increase corresponds to working memory demand and possibly to the orienting response. The increased alpha1 and alpha2 power may be a manifestation of a top-down mechanism revealing control over the execution of a response. The area-specific, task-related, and frequency-dependent changes of EEG complexity measures indicate frontally increasing complexity during the early part of the CNV in the beta frequency bands, which underscores the importance of this region in the mechanisms of anticipatory behavior. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the mechanisms underlying movement preprogramming in situations where informative but ambiguous precue information is used. In a response precuing task that involved flexion or extension movements with the right or left index finger, a spatially compatible precue conveyed partial information about side, about direction, no parameter information (ambiguous condition), or no information at all. Advance movement preparation was indicated by reaction-time shortening for all informative precue conditions. The analysis of stimulus- and response-locked lateralized readiness potential onsets revealed a clear and exclusive motoric origin of the ambiguous-precue benefit. Additional analyses ruled out a strategic trial by trial choice of just one of the two ambiguous alternatives and provided evidence for a parallel preparation of both response alternatives when information only about direction or ambiguous precue information is provided. [ABSTRACT FROM AUTHOR]

Abstract It is well established that reaction time (RT) is shorter when a response signal is preceded by a warning signal, because the warning signal causes the participant to prepare for the upcoming response. A review of chronometric and psychophysiological studies reveals the prevailing view that this temporal preparation operates mainly at a motor level speeding up rather late processes. To assess the locus of this preparation effect, we conducted two experiments employing the lateralized readiness potential (LRP). Contrary to this prevailing view, the results of both experiments clearly indicate that temporal preparation enhances the processing speed of relatively early processes, because a manipulation of temporal uncertainty affected RT, the P300 latency, and the stimulus-to-LRP interval but not the LRP-to-keypress interval. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The effects of mental fatigue on planning and preparation for future actions were examined, using a task switching paradigm. Fatigue was induced by “time on task,” with subjects performing a switch task continuously for 2 hr. Subjects had to alternate between tasks on every second trial, so that a new task set was required on every second trial. Manipulations of response–stimulus intervals (RSIs) were used to examine whether subjects prepared themselves for the task change. Behavioral measurements, event-related potentials (ERPs), and mood questionnaires were used to assess the effects of mental fatigue. Reaction times (RTs) were faster on trials in which no change in task set was required in comparison with switch trials, requiring a new task set. Long RSIs were used efficiently to prepare for the processing of subsequent stimuli. With increasing mental fatigue, preparation processes seemed to become less adequate and the number of errors increased. A clear poststimulus parietal negativity was observed on repetition trials, which reduced with time on task. This attention-related component was less pronounced in switch trials; instead, ERPs elicited in switch trials showed a clear frontal negativity. This negativity was also diminished by time on task. ERP differences between repetition and switch trials became smaller with increasing time on task. [ABSTRACT FROM AUTHOR]

Effects of movement advance information were assessed on the prestimulus amplitude of the lateralized readiness potential (LRP), on the contingent negative variation (CNV), and on reaction time (RT). In a precuing paradigm with movement parameters hand, direction, and force, partial precues provided advance information about either hand alone, hand plus force, or hand plus direction, and the full precue specified all response parameters. The full precue produced the shortest RTs and the largest CNV amplitude, precuing hand and force or hand and movement direction produced somewhat slower RTs and a somewhat smaller CNV amplitude, and precuing only hand yielded slowest RTs and the smallest CNV amplitude. In contrast, the LRP amplitude was largest for the full precue and was the same for the remaining precues. The CNV appears to index the central assembling of a motor program, and the LRP represents the implementation of the program at more peripheral levels. [ABSTRACT FROM AUTHOR]

The topography of the postimperative negative variation (PINV) was analyzed in participants with high and low scores on the German version of the Schizotypal Personality Questionnaire. Scalp amplitude and Laplacian maps of the terminal contingent negative variation (tCNV) and PINV and the time course of the PINV were compared between the two groups. CNV and PINV were induced with a delayed matching-to-sample task, in which the pattern of the imperative stimulus was either clearly or ambiguous matched to one of the two diamonds simultaneously presented as a warning stimulus 4.0 s earlier. Electroencephalograms were recorded with a DC amplifier (32 channels). Negativity increased from tCNV to PINV, especially at frontal sites, and the PINV was larger under ambiguous than under clear matching conditions. Low-scoring participants showed a right-sided predominance of the PINV, which was absent in high-scoring participants. These results resemble differences in the topography of the PINV between healthy control participants and those with schizophrenia under identical experimental conditions and suggest functional differences between tCNV and PINV. [ABSTRACT FROM AUTHOR]

This study focused on the covariation of response speed and event-related potentials during response preparation and on whether these variations can be brought under experimental control. Two SI-S2 choice response tasks with temporal uncertainty were conducted. In Experiment I, SI was 100% informative. Fast subjects showed larger P3s with SI than slow subjects. The terminal CNV (tCNV) increased intraindividually with response speed. In Experiment 2, 50% of SIs were uninformative and the visual display was designed to attract more attention. Effects of information were found on P3 amplitude, on the topography of tCNV, and on the temporal distribution of response rimes. Interindividual differences disappeared in Experiment 2. The results suggest that group differences in Experiment I were due to different strategies of allocating visual attention, Interindividual variations of strategy showed a pattern of effects different from intraindividual variations of efficiency. [ABSTRACT FROM AUTHOR]

Psychophysiological research on preparedness has previously focused on autonomic nervous system parameters. The present study used electrocortical indices of fear conditioning. Subjects (n = 10) were tested under fear-relevant and fear-irrelevant conditions (I week apart, order of conditions counterbalanced). Each condition comprised acquisition and extinction sessions. The contingent negative variation (CNV) was elicited in anticipation of forewarned slides (fear relevant: small animals; fear irrelevant: landscapes). In acquisition, reinforced conditioned stimulus (CS+) (but not nonreinforced conditioned stimulus [CS-]) slides were followed by white noise as an unconditioned stimulus (UCS). In extinction, the UCS was omitted. In the fear-relevant condition, CNV amplitude was significantly larger for CS+ than CS- in both acquisition and extinction. In the fear-irrelevant condition, CNV differentiation between CS+ and CS- was weak in both sessions. CNV was significantly larger in the fear-relevant than in the fear-irrelevant condition, for CS+ but not CS-. The findings are consistent with a preparedness interpretation and suggest that CNV under such circumstances may represent an automatic affective response to fear-relevant stimuli. Electrocortical measures could be particularly useful in examining information processing mechanisms in phobia and cognition-affect relationships generally. [ABSTRACT FROM AUTHOR]

The present study employed event-related potentials (ERPs) of the brain to improve the understanding of temporal processing. A reproduction paradigm was realized by presenting a visual stimulus (illuminated screen) for intervals of varying length. A few seconds after presentation of such standard intervals the visual stimulus was switched on again and subjects were asked to reproduce the duration of the standard interval by turning off the illumination after a corresponding interval had elapsed. The length of standard intervals varied randomly with each of the following lengths being presented 20 times: 1, 2, 3, 4, 6, and 8 s. Reproduction was accurate for standard intervals up to 3 s but deteriorated with increasing interval length. Brain potentials during reproduction intervals of 1-3 s differed from those recorded during the longer intervals. A CNV-like slow negative shift developed during the shorter reproduction intervals. Negativity was reduced or even absent, when subjects had to reproduce standard intervals of 4 s or longer. The ERP results suggest that intervals shorter than 3-4 s may evoke a processing mode that is qualitatively different from the one dominating when periods in the range of several seconds have to be processed. [ABSTRACT FROM AUTHOR]

The present study investigated the relationship between lateralized sensorimotor activation and lateralized elevation of electrodermal activity. Within a two-stimulus reaction time paradigm skin conductance responses (SCRs) were recorded from both hands, while subjects awaited and performed unilateral sensorimotor tasks. A tactile warning stimulus was applied 6 s prior to a tactile imperative stimulus either to the same or to the contralateral hand; the imperative stimulus was associated with a choice reaction time task. Task-dependent lateral asymmetry with larger skin conductance responses contralateral to the involved hemisphere indicated contralateral facilitatory processes rather than inhibition. This asymmetry disappeared with repeated stimulation (across trials). Only right-hand (left hemispheric) tasks proved to be sensitive to habituation. The asymmetry, recorded in slow brain potentials (SPs), assured that lateralized cortical processing was induced through the present experimental arrangement. The brain potentials specified the time course of lateralized processing, exhibiting larger late negative shifts at the precentral areas contralateral to the hand involved in the sensorimotor task and larger early negativity and a more pronounced positive evoked potential (late positive complex, LPC) contralateral to the hand stimulated by the tactile warning stimulus. [ABSTRACT FROM AUTHOR]

The contingent negative variation (CNV) can be spontaneously followed in psychiatric patients by a post- imperative negative variation (PINV), and also in normal subjects who have undergone sufficiently intense interference during the CNV paradigm. Our hypothesis was that sleep deprivation could facilitate the induction of a spontaneous PINV which would reflect a transient psychophysiological perturbation. The present experiment investigates the influence of total sleep deprivation on event-related potentials (PINV, CNV, auditory evoked potential), behavioral performance (reaction time), and autonomic response (heart rate). Nineteen subjects participated in the experiment. The subjects were studied before and after 2 consecutive nights of total sleep deprivation. The event-related potentials resulted from the summation of 16 trials. The warning stimulus (tone burst) was followed 1.5 sec later by an imperative stimulus (continuous tone) which was stopped by the subject. After the deprivation, 6 subjects underwent the CNV paradigm with interference. None of the subjects showed a PINV after sleep deprivation either spontaneously or with an interference which had induced it under non-deprived conditions. The CNV and auditory evoked potential (AEP) amplitudes were reduced after the deprivation whereas AEP latencies increased. The unobtainable PINV after sleep deprivation and the low CNV amplitude could suggest a common neurophysiological origin for these two slow potentials. [ABSTRACT FROM AUTHOR]

A problem frequently encountered by investigators measuring scalp-recorded DC potentials is baseline drift artifact. The sources of baseline drift are many and it is often very difficult to remove drift from the primary data. The problem is particularly acute when long recording epochs are under investigation. The present paper proposes a software solution. A FORTRAN IV computer program defines drift as a significant linear trend in prestimulus voltage on successive experimental trials. When drift Is determined to be present. its slope is computed and statistically removed from the data in the poststimulus (response) period. A sample data set is included which demonstrates the method's marked improvement of signal-to-noise rats, as represented by reduced error variance and improved statistical discrimination between the independent variables of an experiment. [ABSTRACT FROM AUTHOR]

Thirteen subjects low in fear of mutilation and 11 subjects high in this fear were exposed to repeated presentations of a 6-sec tone followed by slides depicting a mutilated body or a 6-sec tone of a different frequency paired with a slide of a neutral scene. For both groups, the N140 component of the evoked potential was larger following the signal for gruesome slides. Slow EEG activity displayed two negative waves. Notably, the late CNV wave was present even though a motor response was not required at the end of the foreperiod. Overall, high-fear subjects' early waves tended to be larger preceding neutral scenes than gruesome slides, whereas Low-fear subjects showed a trend in the opposite direction. Similar but largely nonsignificant trends were present for the late wave. Heart rate reactions of both groups in the foreperiod included an early deceleration, acceleration, and a late deceleration. Among high-fear subjects both the acceleratory and late deceleratory limbs were greater preceding mutilation than neutral slides. In contrast, low-fear subjects' reactions lacked the acceleratory reaction and did not vary as a function of type of warning signal. These results, therefore, indicate differential autonomic patterns of anticipation of affective stimulation as a function of individual differences in fear. [ABSTRACT FROM AUTHOR]

Stimuli were delivered to 12 subjects in a sequence that included regularly occurring standard tone pips, random warning tone pips, and random white noise bunts. Half the noise bursts were preceded by warning tones (high probability), and half were not (low probability). There were four runs, each having one of two noise burst intensities, and each having the warning tone and noise bursts either both task-relevant to a reaction time task or both task-irrelevant. Event-related potentials (ERPs) were obtained by signal averaging in F[SUBz], C[SUBz], P[SUBz], and eye leads. The P3 to the warning tone was largest in P[SUBx] and was not affected by task relevance. CNVs preceded all the high probability noise bursts. These CNVs had an amplitude of 5μV even when the bursts were task irrelevant. Low probability noise bursts elicited larger P3s in all leads for the task-irrelevant conditions, but only in P[SUBz] for the task-relevant conditions. In C[SUBz], the amplitudes of N1, P2, and P3 to the high probability, task-relevant noise bursts correlated with the amplitude of the preceding CNV. [ABSTRACT FROM AUTHOR]

Ten-, 14-, and 19-yr-olds participated in a simple RT task with S-sec foreperiod. CNV waveforms contained an early and a late negative component, and comparable deceleratory limbs characterized the cardiac waveforms. The ]9-yr-olds* early cardiac deceleration underwent intersession habituation and the analogous CNV response intra-session diminution; both processes were absent in younger subjects. Only young adults exhibited steady growth of late cardiac and CNV waves across both sessions. There were no developmental differences in basal body movement or anticipatory slowing of somatic activity or cardiac rate. However, l0-yr-olds had faster basal heart rates and larger4ccelerntory cardiac responses within the foreperiod than either older group. The results demonstrated partial dissociation of somatic and cardiac activity under the present experimental conditions. The overall results underscore the need for developmental psychophysiological research including childhood and adolescence. [ABSTRACT FROM AUTHOR]

There have been a number of reports of a cerebral potential occurring at about the time of an expected but absent stimulus when absence provided significant information for the subject. This potential consists primarily of a positive peak occurring with a latency of about 300 msec with respect to the lime of stimulus absence and is referred to as an emitted P300 potential. It has been conjectured that the emitted P300 is a manifestation of the same process that underlies the evoked P300. Evidence supporting this hypothesis is provided by demonstrating that both the evoked and emitted P300 potentials are similarly affected by variation in event probability. A paradigm was used in which click presence and absence provided information. The relative probability of click presence and absence was experimentally manipulated. Both evoked and emitted P300 amplitude responded in the same way to event probability, larger for the less frequent event and smaller for the more frequent event [ABSTRACT FROM AUTHOR]

Weak lead stimulation can modify the human startle reflex. It is proposed that, with the aid of physiological measures taken in the interval between lend and startle stimuli, this paradigm offers a promising method of Investigating different levels of central processing, the operation of a short time-constant as opposed to a long time-constant stem, and the operation of an orienting-attentional as opposed loan intensity-dependent activational system. [ABSTRACT FROM AUTHOR]

Multichannel recording of scalp CNV (Contingent Negative Variation and RT (Reaction Time) was carried out on 12 normal adult Ss in a fixed foreperiod RT experiment. Single trial responses were stored on digital tape and averaged off-line. Strict control over eye movement artifact was exerted through fixation technique, coupled with mechanical and electro-oculographic monitoring of movement. Analysis of single-trial data gave an intra-individual picture of correlation apparently in conflict with the across-Ss picture gained from averages. A rationalization is attempted of these results and some evidence is offered that, in the individual S, a negative and probably nonlinear relationship holds between CNV amplitude and RT. Analysis of average data demonstrates the distribution of CNV across the scalp and shows a lack of correlation between CNV and RT in prefrontal areas, in contrast with that found in central-parietal areas. It is suggested that the CNV is an index of functionally different processes in these areas. [ABSTRACT FROM AUTHOR]

The topographic distribution of the amplitudes of the contingent negative variation (CNV) recorded along the midline at the anterior, central, and posterior regions of the human scalp varied as a function of type of information processing demanded. A parietal-dominant CNV was found when active problem-solving behavior was required. A central-dominant CNV was evident in a disjunctive reaction time task. The results are interpreted as evidence supporting a model of cortical function which predicts shifts in cortical involvement as a function of type of task demands. A late positive component (LPC) of the average evoked potential was also found to vary as a function of stage of learning, recording sites, and an attitudinal dimension measured by Rotter's internal-external locus of control scale. [ABSTRACT FROM AUTHOR]

The CNV was measured from 5 female and 5 male Ss during a pitch discrimination task with two levels of difficulty. It was found that females had larger CNVs during easy trials titan during difficult trials. They also had larger CNVs for difficult trials in which they made incorrect judgments than for difficult trials in which they made correct judgments. The effect of difficulty and of correctness on the CNV is interpreted as a distraction phenomenon. [ABSTRACT FROM AUTHOR]

Presents the abstracts that will be presented in the poster session of the Society for Psychophysiological Research conference. "Prepulse Inhibition and the Psychological Refractory Period," by Melissa L. Rawley; "Sex Differences in Event Related Brain Responses in Semantic Priming," by Jerome Daltrozzo and Boris Kotchoubey; "Neuroelectric Assessment of Ecstasy Use in Young Adults," by Brian A. Lopez and John Polich.