The cognitive mechanisms underlying deception: An event-related potential study

Smoking/nicotine improves cognitive performance for a variety of tasks. In most cases, reaction time (RT) is generally shorter after smoking/nicotine. While there may be some slight facilitation of stimulus-evaluation processing, most of the RT effects of nicotine appear to take place following the response-selection stage. This study investigated possible effects (in smokers) of smoking/nicotine on response preparation and execution processes using the lateralized readiness potential (LRP). On each trial, a warning stimulus preceded an imperative stimulus by 1.2s. The warning stimulus completely specified the correct response to the imperative stimulus. The study was completed in two morning sessions in which 4 cigarettes were smoked in each session. The nicotine yield of the cigarettes varied between sessions (0.05mg or 1.1mg). Maximum amplitudes of both the stimulus and response-locked LRPs were larger in the 1.1 mg session. For both stimulus- and response-locked LRPs, smoking the 1.1 mg cigarette (but not the 0.05 mg cigarette) shortened onset latency. However, the magnitude of the effect was much larger for the stimulus-locked LRPs, suggesting that response preparation is facilitated by smoking/nicotine to a greater degree than response execution.

Almost 40 years ago two papers appeared with an important impact on the psychophysiological and neurophysiological literature. Kornhuber and Deecke (1965) published their first recordings of the Bereitschaftspotential (BP), brain activity preceding a self-paced movement, while Walter et al. (1964) presented their study on the contingent negative variation (CNV). Recently Jahanshahi and Hallett (2003) edited a book on the BP, demonstrating that the topic is still of interest for many researchers. Both potentials reflect processes that are future-directed, coupled to an upcoming event that will take place within a few seconds. The subject, whose brain activity is recorded, has a notion about what is going to happen and when it is going to happen. The event may be the execution of a self-paced movement or the presentation of an informative stimulus with behavioral consequences. Preparation of a movement or anticipation of an upcoming stimulus goes along with behaviorally hidden processes that result in a better performance. Apart from the event, the timing is an essential aspect of each future-directed behavior. Certainty about when an event will take place allows better preparation and, therefore, a more adequate behavioral result. Both readiness potential (RP) and CNV are recorded under experimental conditions. A real life situation is transferred to circumstances that can be kept constant, in order to allow conclusions about the only experimental factor the investigator is interested in. The investigator asks the subject to do something, and the subject agrees to do so. All experiments are based upon this implicit agreement. If we ask a subject to press a button every 5 s, we call that movement self-paced because the subject does it voluntarily. However, at the same time he has to keep the instruction in a working memory system for the time of the experiment. In animal research we train subjects and reinforce the behavior we would like to see. Many monkey studies have been done in which BP, CNV, or unit activity have been recorded. Under these circumstances the animal is doing what he does in order to get the reinforcement. Thus, in all such experiments it is not only the task at hand but also the impending reinforcement, which has to be taken into account when interpreting the data. Grunewald and Grunewald-Zuberbier (1983, 1984) were among the first to record slow potentials not only prior to a movement, but also during the movement. Lang et al. (1984) also recorded brain activity during stimulus-guided movements. Under these circumstances slow potentials reflect the ongoing control of motor activity. In a more abstract situation subjects might be involved in memory search processes, which are also accompanied by slow waves, now reflecting the search for a specific item among a number of alternatives (Ruchkin et al., 1995; Rosler et al., 1995). While slow potentials in such settings reflect an on-line control of specific brain functions, this is not the topic of the present issue. Rather we concentrate on the use of slow potentials in anticipatory behavior. The late wave of the CNV is a combination of a movement-preceding negativity (MPN) and a stimulus preceding negativity (SPN; Brunia, 1988). To investigate anticipatory attention a time estimation task was used, in which both slow potentials can be separated in time. In the first contribution, van Boxtel and Bocker give an overview of the studies of the SPN. They show that the SPN is not restricted to the time estimation task, and that, apart from anticipatory attention, an emotional anticipation plays a role in the emergence of the SPN, too. While van Boxtel and Bocker stayed away from the CNV in order to study anticipatory processes not confounded with any motor activity, Leuthold, Sommer, and Ulrich use the CNV explicitly to investigate motor preparation. In their review they show that the application of the lateralized RP (LRP), derived from the CNV and not from the RP, is an interesting tool with which to investigate behaviorally hidden stages in motor preparation. Next, Journal of Psychophysiology 18 (2004) 59–60 © 2004 Federation of European Psychophysiology Societies

Cognitive load significantly influences learning effectiveness. All the three types of cognitive load—intrinsic, extraneous, and germane—are important for guiding teachers in preparing effective instructional designs for students. However, the techniques used to assess the relationship between brain activity and cognitive load during learning activities require further investigation. This study preliminarily examined cognitive load during mathematics computations based on cognitive-load theory. We used event-related potentials to compare carryover and without carryover additions under three types of stimuli (uncoloured Arabic numerals, colourful Arabic numerals, and Chinese numerals) to measure learners’ cognitive load. According to the concept and rationale of cognitive-load theory, the design defined the extraneous and germane cognitive load to measure the N1 and P2 components and the relevant behavioural data. The highest P2 amplitude was observed in the Chinese numerals condition as extraneous cognitive load, and the N1 component was observed in the colourful Arabic numerals condition as germane cognitive load. Thus, both components may play an important role in extraneous and germane cognitive load. Additionally, these exhibit negative correlations during mathematical computations. This study’s findings and implications offer insights into future ways for assessing cognitive load using brain imaging techniques and potential applications for brain–computer interfaces.

Reaction time (RT), the most common measure of CNS efficiency, shows intra- and inter-individual variability. This may be accounted for by hemispheric specialization, individual neuroanatomy, and transient functional fluctuations between trials. To explore RT on these three levels, ERPs were measured in a visual 4-choice RT task with lateralized stimuli (left lateral, left middle, right middle, and right lateral) in 28 healthy right-handed subjects. We analyzed behavioral data, ERP microstates (MS), N1 and P3 components, and trial-by-trial variance. Across subjects, the N1 component was contralateral to the stimulation side. N1-MSs were stronger over the left hemisphere, and middle stimulation evoked stronger activation than lateral stimulation in both hemispheres. The P3 was larger for the right visual field stimulation. RTs were shorter for the right visual hemifield stimulation/right hand responses. Within subjects, covariance analysis of single trial ERPs with RTs showed consistent lateralized predictors of RT over the motor cortex (MC) in the 112-248ms interval. Decreased RTs were related to negativity over the MC contralateral to the stimulation side, an effect that could be interpreted as the lateralized readiness potential (LRP), and which was strongest for right side stimulation. The covariance analysis linking individual mean RTs and individual mean ERPs showed a frontal negativity and an occipital positivity correlating with decreased RTs in the 212-232ms interval. We concluded that a particular RT is a composite measure that depends on the appropriateness of the motor preparation to a particular response and on stimulus lateralization that selectively involves a particular hemisphere.

Attention-related modulation of frontal midline theta oscillations in cingulate cortex during a spatial cueing Go/NoGo task

The major purpose of the present study was to further elucidate dopaminergic modulation of sensorimotor processing in healthy human subjects. To more specifically analyze dopaminergic effects on premotor and motor stages of sensorimotor processing, lateralized readiness potentials (LRPs) were obtained. In a randomized double-blind crossover design, either 0.075 mg of the D1/D2 dopamine (DA) agonist pergolide or placebo were administered to 12 healthy male volunteers ranging from 19 to 25 years in age. The subjects performed a two-choice visual reaction time task. In addition to behavioral measures, such as response speed and error rate, stimulus-locked LRP (S-LRP) and response-locked LRP (LRP-R) latencies were determined. To better dissociate potential central and peripheral motor effects, measures of response dynamics and response-locked electromyogram (EMG-R) recordings were also obtained. Pergolide reliably enhanced speed of stimulus-related information processing as indicated by shorter S-LRP latencies while LRP-R latencies, reaction time, and indicators of response dynamics were not influenced by DA agonistic treatment. Furthermore, lower EMG-R amplitudes and an increased number of wrong-hand responses were observed under pergolide compared to placebo. The results indicate that dopaminergic neurotransmission effectively modulates early perceptual and cognitive stages of information processing as suggested by neural network models of the functional role of prefrontal DA. The lack of an effect on aspects of motor processing may be due to a higher capacity of the nigrostriatal compared to the mesocortical DA system to compensate pharmacologically induced changes in dopaminergic activity.

Anodal transcranial direct current stimulation (tDCS) over the motor cortex is considered a potential treatment for motor rehabilitation following stroke and other neurological pathologies. However, both the context under which this stimulation is effective and the underlying mechanisms remain to be determined. In this study, we examined the mechanisms by which anodal tDCS may affect motor performance by recording event-related potentials (ERPs) during a cued go/nogo task after anodal tDCS over dominant primary motor cortex (M1) in young adults (Experiment 1) and both dominant and non-dominant M1 in older adults (Experiment 2). In both experiments, anodal tDCS had no effect on either response time (RT) or response-related ERPs, including the cue-locked contingent negative variation (CNV) and both target-locked and response-locked lateralized readiness potentials (LRP). Bayesian model selection analyses showed that, for all measures, the null effects model was stronger than a model including anodal tDCS vs. sham. We conclude that anodal tDCS has no effect on RT or response-related ERPs during a cued go/nogo task in either young or older adults.

Slow potential changes and choice reaction time as a function of interstimulus interval

When the lateralized readiness potential (LRP) is recorded in stimulus-response compatibility (SRC) tasks, two processes may overlap in the LRP, stimulus-driven response priming and activation based on response selection rules. These overlapping processes are hard to disentangle with standard analytical tools. Here, we show that Residue Iteration Decomposition (RIDE), based on latency variability, separates the overlapping LRP components from a Simon task into stimulus-driven and response-related components. SRC affected LRP amplitudes only in the stimulus-driven component, whereas LRP onsets were affected only in the response-locked component. Importantly, the compatibility effect in reaction times was more similar to the effect in the onsets of the RIDE-derived response-locked LRP component than in the unseparated LRP. Thus, RIDE-separated LRP components are devoid of distortions inherent to standard LRPs.

BackgroundEvent-related potentials (ERPs) may be used as a highly sensitive way of detecting subtle degrees of cognitive dysfunction. On the other hand, impairment of cognitive skills is increasingly recognised as a hallmark of patients suffering from multiple sclerosis (MS). We sought to determine the psychophysiological pattern of information processing among MS patients with the relapsing-remitting form of the disease and low physical disability considered as two subtypes: 'typical relapsing-remitting' (RRMS) and 'benign MS' (BMS). Furthermore, we subjected our data to a cluster analysis to determine whether MS patients and healthy controls could be differentiated in terms of their psychophysiological profile.MethodsWe investigated MS patients with RRMS and BMS subtypes using event-related potentials (ERPs) acquired in the context of a Posner visual-spatial cueing paradigm. Specifically, our study aimed to assess ERP brain activity in response preparation (contingent negative variation -CNV) and stimuli processing in MS patients. Latency and amplitude of different ERP components (P1, eN1, N1, P2, N2, P3 and late negativity -LN) as well as behavioural responses (reaction time -RT; correct responses -CRs; and number of errors) were analyzed and then subjected to cluster analysis.ResultsBoth MS groups showed delayed behavioural responses and enhanced latency for long-latency ERP components (P2, N2, P3) as well as relatively preserved ERP amplitude, but BMS patients obtained more important performance deficits (lower CRs and higher RTs) and abnormalities related to the latency (N1, P3) and amplitude of ERPs (eCNV, eN1, LN). However, RRMS patients also demonstrated abnormally high amplitudes related to the preparation performance period of CNV (cCNV) and post-processing phase (LN). Cluster analyses revealed that RRMS patients appear to make up a relatively homogeneous group with moderate deficits mainly related to ERP latencies, whereas BMS patients appear to make up a rather more heterogeneous group with more severe information processing and attentional deficits.ConclusionsOur findings are suggestive of a slowing of information processing for MS patients that may be a consequence of demyelination and axonal degeneration, which also seems to occur in MS patients that show little or no progression in the physical severity of the disease over time.

Effect of Gumchewing with CNV Paradigm on Event-related Potential

The temporal selectivity of additive factor effects on the reaction process revealed in ERP component latencies

Ulrich, Leuthold, and Sommer (1998) suggested that movement preparation at the level of the motor cortex, as indexed by the lateralized readiness potential (LRP), proceeds in a strongly hierarchical fashion, where parameters other than response hand are prepared only if all the movement parameters are known. These conclusions were based on an experiment where a precue provided information about response hand, direction of finger movement, and movement force. To assess the generality of these findings, we replaced the force parameter with response finger. LRP indicated that preparation of the required finger is possible even when preliminary information is incomplete. Therefore, movement preparation appears to follow different rules when anatomical relationships (hand and finger) are concerned as compared to functional parameters like movement direction. On the other hand, at a limb-unspecific level, as indicated by the contingent negative variation, we confirmed evidence for parallel programming of all movement parameters.

A growing body of research has demonstrated that affect modulates cognitive control modes such as proactive and reactive control. Several studies have suggested that positive affect decreases proactive control compared to neutral affect. However, these studies only focused on the valence of affect and often omitted two of its components: arousal and approach motivation. Therefore, we designed the present study to test the hypothesis that cognitive control modes would differ as a function of arousal and approach motivated positive affect. In our study, we used an AX-continuous performance task (AX-CPT), commonly used to examine shifts in proactive and reactive control. We also measured P3b, contingent negative variation (CNV), N2 and P3a components of event-related brain potentials (ERPs) as indicators of the use of cognitive control modes. The findings of the present study demonstrated that approach motivated positive affect modified only the P3b and the CNV without effects on the N2 and P3a components. However, arousal induced by pictures modified P3b, CNV and N2 amplitudes. Specifically, the P3b amplitude was larger, and CNV amplitude was less negative in the high than in the low-approach motivated affect. In contrast, the P3b amplitude was larger and both the CNV and N2 amplitudes more negative in low- compared with high-arousal conditions. These ERP results suggest that approach motivated positive affect enhanced proactive control with no effect on reactive control. However, arousal influenced both proactive and reactive control. High arousal decreased proactive control and increased reactive control compared to low arousal. The present study provides novel insights into the relationship between affect, specifically, arousal and approach motivated positive affect and cognitive control modes. In addition, our results help to explain discrepancies found in previous research.

Abnormalities in motor skills have been regarded as part of the symptomatology characterizing autism spectrum disorder (ASD). It has been estimated that 80 % of subjects with autism display "motor dyspraxia" or clumsiness that are not readily identified in a routine neurological examination. In this study we used behavioral measures, event-related potentials (ERP), and lateralized readiness potential (LRP) to study cognitive and motor preparation deficits contributing to the dyspraxia of autism. A modified Posner cueing task was used to analyze motor preparation abnormalities in children with autism and in typically developing children (N = 30/per group). In this task, subjects engage in preparing motor response based on a visual cue, and then execute a motor movement based on the subsequent imperative stimulus. The experimental conditions, such as the validity of the cue and the spatial location of the target stimuli were manipulated to influence motor response selection, preparation, and execution. Reaction time and accuracy benefited from validly cued targets in both groups, while main effects of target spatial position were more obvious in the autism group. The main ERP findings were prolonged and more negative early frontal potentials in the ASD in incongruent trials in both types of spatial location. The LRP amplitude was larger in incongruent trials and had stronger effect in the children with ASD. These effects were better expressed at the earlier stages of LRP, specifically those related to response selection, and showed difficulties at the cognitive phase of stimulus processing rather that at the motor execution stage. The LRP measures at different stages reflect the chronology of cognitive aspects of movement preparation and are sensitive to manipulations of cue correctness, thus representing very useful biomarker in autism dyspraxia research. Future studies may use more advance and diverse manipulations of movement preparation demands in testing more refined specifics of dyspraxia symptoms to investigate functional connectivity abnormalities underlying motor skills deficits in autism.