P300 amplitude age reductions are not caused by latency jitter

Studies of the event-related potentials (ERPs) P3a/P3b have given insights into age effects on cognitive processes in the brain, and it has been established that latency increases and amplitude decreases with age. However, if latency jitter, that is, variation in single trial latencies, is larger in elderly than in younger participants, this may create an artificial age-amplitude correlation. The aim of this article is to test whether correction for latency jitter affects the P3a/P3b age correlations. One hundred thirty-three healthy adults (20-88 years old) went through a 3-stimuli visual oddball paradigm. Latency jitter was corrected by use of a Maximum Likelihood Estimation method. The results showed that corrections for latency jitter did not significantly affect the correlations between P3a/P3b and age. It is concluded that previous reports of amplitude reduction as a function of age seem to be valid regardless of whether latency jitter correction has been applied.     

Life-span changes in P3a

The relationship of visual P3a to age was investigated in a life-span sample. The aims of the study were (1) to assess to what extent P3a, relative to P3b, decreases with increasing age; (2) To assess at which recording sites the relationship between P3a and age is strongest; (3) to investigate whether the relationship between P3a and age is best described as linear or nonlinear. One hundred and three well-functioning adults, 20-92 years old, were given a health interview, a battery of neuropsychological tests, and performed a visual three-stimuli oddball ERP task yielding both a P3a and a P3b. P3a and age was moderately correlated, with coefficients reaching.53 (Cz) and -.52 (Pz) for latency and amplitude, respectively. P3b was to a much lesser extent related to age. Generally, the age-P3a relationship was strongest at midline and central electrodes. Finally, the relationship between age and P3a was best described as linear. P3a seems selectively more impaired with age than P3b, but this impairment seems less pronounced at Fz than at Cz and Pz. There is a need for complex theoretical integration of these and previous findings.     

Habituation of P3a and P3b brain potentials in men engaged in extreme sports

Do person characteristics determine when novel, attention-grabbing stimuli loose their novelty? The aim of the present study was to investigate habituation of the visual event-related potentials (ERP) P3a and P3b in men that (1) were engaged in extreme sports, (2) had extremely high scores on the Impulsivity Sensation Seeking scale of the Zuckerman–Kuhlman Personality Questionnaire (ZKPQ), yet were not engaged in extreme sports, or (3) had extremely low scores on ZKPQ. The results showed that P3a habituated significantly more in extreme sporters than in the other groups. The same was not found in comparison of the high and the low ZKPQ scorers. There were not differences between the groups in overall amplitude. It is concluded that ERP habituation may be more relevant than mere amplitude to the sensation seeking trait in extreme sporters, and that they differ from others in ERPs related to automatic alerting-related processes, not controlled cognitive processing.     

Stimulus context determines P3a and P3b

P300 differences for target (.10), nontarget (.10), and standard tones (.80) were assessed using a three-stimulus oddball paradigm in which participants responded only to the target ( n = 12). Target/standard (easy or difficult) and nontarget/standard (large or small) pitch differences were manipulated orthogonally. In all conditions, target tones elicited a parietal P300, which was affected only by the target/standard discrimination ease. Nontarget in the easy/large and difficult/small conditions elicited a parietal but smaller P300 than the target but in the easy/small condition elicited similar ERPs to the standard. However, nontarget stimuli in the difficult/large condition elicited an anterior maximum and earlier P300 (P3a) component. The findings suggest that target P300s are not influenced by the nontarget stimulus configuration, whereas the nontarget P300 outcomes are determined directly by the stimulus context. The theoretical implications are discussed.     

抑郁症患者的多导联听觉P3a和P3b事件相关电位研究

目的：研究抑郁症患者的16导联听觉事件相关电位P300的脑区强度分布。方法：选择抑郁症患者27例和正常人30名，用脑诱发电位仪记录受试者16导事件相关电位P3a和P3b，分析受试者在额区、颞区、中央区和顶区的P300幅度分布，比较抑郁症患者和正常对照组的显著差异。结果：抑郁症患者的P3a、P3b幅度的额区／顶区比值较正常对照组都发生显著降低（P〈0．01），颞区／顶区比值也显著降低（P〈0．01），中央区／顶区比值同样显著降低（P〈0．01），另外，抑郁症患者的额1区／额2区P3b幅度比值显著降低。结论：通过多导联记录P300，并分析P300幅度在脑区间的相对强弱关系，将能获得抑郁症患者的异常ERPs特征，并能提示主要相关脑区的功能状况，因此，有助于提高P300诊断抑郁症的特异性水平。     

Arousal and valence effects on event-related P3a and P3b during emotional categorization

Due to the adaptive value of emotional situations, categorizing along the valence dimension may be supported by critical brain functions. The present study examined emotion–cognition relationships by focusing on the influence of an emotional categorization task on the cognitive processing induced by an oddball-like paradigm. Event-related potentials (ERPs) were recorded from subjects explicitly asked to categorize along the valence dimension (unpleasant, neutral or pleasant) deviant target pictures embedded in a train of standard stimuli. Late positivities evoked in response to the target pictures were decomposed into a P3a and a P3b and topographical differences were observed according to the valence content of the stimuli. P3a showed enhanced amplitudes at posterior sites in response to unpleasant pictures as compared to both neutral and pleasant pictures. This effect is interpreted as a negativity bias related to attentional processing. The P3b component was sensitive to the arousal value of the stimulation, with higher amplitudes at several posterior sites for both types of emotional pictures. Moreover, unpleasant pictures evoked smaller amplitudes than pleasant ones at fronto-central sites. Thus, the context updating process may be differentially modulated by the affective arousal and valence of the stimulus. The present study supports the assumption that, during an emotional categorization, the emotional content of the stimulus may modulate the reorientation of attention and the subsequent updating process in a specific way.     

Wavelet Analysis of P3a and P3b

Target/standard discrimination difficulty and the degree of stimulus "novelty" were manipulated systematically in a three-stimulus oddball task to assess how these variables affect target and non-target P300 scalp distributions for visual stimuli. Wavelet transformation (WT) analyses were performed on the non-target (P3a) and target (P3b) ERPs to assay how the underlying electroencephalographic (EEG) activity was affected by both the difficulty and novelty factors. When target/standard discrimination was easy, P300 amplitude was higher for the target than the non-target across all electrode sites, and both demonstrated parietal maximums. In contrast, when target/standard discrimination was difficult, non-target amplitude (P3a) was higher and earlier over the frontal/central electrode sites for both levels of novelty, whereas target amplitude (P3b) was greater parietally and occurred later than the non-target components and was generally unaffected by non-target novelty level. The WT analyses indicated that appreciable theta activity was related to the more novel non-target stimuli; primarily target component delta coefficients were affected by the discrimination difficulty variable. The findings suggest that target/standard discrimination difficulty, rather than stimulus novelty, determines P3a generation for visual stimuli but that the underlying theta oscillations are differentially affected by stimulus novelty. WT analysis methods are discussed along with the theoretical and neurophysiological implications of the findings.     

P3a and P3b components associated to the neurocognitive evaluation of invalidly cued targets

The present report focuses on evaluating the neurocognitive consequences of the correct or incorrect spatial prediction induced by a spatial cue. Positions in the vertical meridian were cued in order to evaluate the cognitive consequences in the processing of the validly (VC) or invalidly cued (IC) targets. The behavioural responses and the 64 EEG channel were recorded. The late endogenous event-related potential (ERP) induced by target stimuli in VC and IC targets were compared in voltage amplitude, voltage and current source density topographies. The P3a and a late positive complex, possibly P3b were increased in a statistically significant manner in the IC targets with regard to the VC targets. The previous result suggests that subjects prepare to accomplish the task upon specification of the cue, and when the IC target appeared it is treated as a low probability stimulus in a similar manner to deviant stimuli in odd-ball paradigms.     

On the topography of P3a and P3b across the adult lifespan--a factor-analytic study using orthogonal procrustes rotation

The purpose of this study was to investigate whether the activity distribution of P3a and P3b across the scalp changes with age or remains identical. 103 well-functioning adults, 20-90 years, performed a visual three-stimuli oddball ERP task yielding both a P3a and a P3b. The sample was divided into three age groups: 20-44 years, 45-69 years, and 70-90 years. The P3as and P3bs from 20 electrodes were subjected to principal component factor analyses. The unrotated factor matrices from the three different age groups were then compared using orthogonal Procrustes rotation to maximize congruence, and Tucker's coefficient of congruence was used as index of similarity. The results showed that less variance in latency than in amplitude was explained by three factors. Further, for amplitude, the factor structure remained the same for both P3a and P3b across different age groups, implying that the structure of the neurophysiological generation of the P3 amplitude operates similarly at different ages. For P3a and P3b latency the congruence coefficients were weaker, implying that when it comes to latency, the neural generators or parts of the generator circuits are differentially susceptible to the influence of age. It is speculated that a possible reduced temporal synchronicity across electrodes could result in less predictable shifts of the clustering of P3 latency, and may explain the presently observed factor variability with age. Implications of the findings and the utility of Procrustes rotation in ERP studies are discussed.     

Age,physical fitness,and attention: P3a and P3b

The influence of age and fitness on the neuroelectric correlates of attentional orienting and processing during stimulus discrimination were investigated. Younger and older adult participants completed a maximal aerobic exercise test and were separated into higher‐ and lower‐fit groups according to their cardiorespiratory fitness. Task performance and event‐related potential measures were obtained during two‐ and three‐stimulus oddball tasks. Results indicated that fitness may ameliorate or protect against cognitive aging for simple stimulus discriminations. Increases in task difficulty indicated that fitness may not be sufficient to overcome age‐related deficits in stimulus discrimination. Further, fitness did not influence attentional orienting. The findings suggest that fitness‐related changes in cognitive function may originate from other attentional mechanisms. Theoretical implications are discussed.     

Acute exercise has a general facilitative effect on cognitive function: A combined ERP temporal dynamics and BDNF study

This study examined whether acute moderate intensity exercise results in a general or selective improvement in cognitive function. In addition, multiple stimulus‐locked ERP components and serum BDNF levels were assessed to investigate potential neurobiological mechanisms underlying acute exercise effects on select aspects of cognitive performance. Thirty young adults were recruited and participated in exercise and reading control sessions in a counterbalanced order. Following treatments, the Stroop task was administrated, and N1, N2, P3, and N450 components of the ERP waveform were recorded and analyzed. Additionally, blood samples were withdrawn immediately following exercise or rest conditions prior to administration of the Stroop task. Acute exercise facilitated response times for both Stroop congruent and incongruent task conditions, with a similar magnitude of improvement. Larger P3 and reduced N450 amplitudes as well as decreased N450 latency were observed following exercise, but no effects on N1 and N2 components were found. This dose of exercise also did not influence serum BDNF levels. These findings suggest that moderate intensity acute exercise results in a generalized rather than selective improvement in cognition. The facilitation may be related to an increase in attentional or neural resource allocation and conflict detection processes reflected by longer latency endogenous components (P3, N450), but is not influenced by earlier sensory and monitoring processes revealed by earlier ERP components or by serum levels of BDNF.     

Sources of P300 attenuation after head injury: Single-trial amplitude, latency jitter, and EEG power

Single trial amplitude, latency jitter, and electroencephalographic (EEG) power were examined as sources of the group difference in averaged P300 amplitude among 15 traumatically brain injured and 20 control individuals in an auditory oddball paradigm. Mean amplitude of the individual trials was highly correlated with the amplitude of the averaged P300, with little additional unique variance attributable to latency jitter or EEG power. The group difference in P300 amplitude was also explained by the mean amplitude of the single trials. These results support the robustness of the event-related potential averaging technique within the paradigm used.     

On the relation of movement-related potentials to the go/no-go effect on P3

According to Simson et al. [Simson, R., Vaughan, H.G., Jr., Ritter, W., 1977. The scalp topography of potentials in auditory and visual go/nogo tasks. Electroencephalography and Clinical Neurophysiology 43, 864-875], the difference between no-go P3 and go-P3 (the go/no-go effect) is due to overlap of P3 onto the return of the preceding contingent negative variation (CNV) in no-go trials and onto the continuing CNV in go trials. Similarly, according to Kok [Kok, A., 1986. Effects of degradation of visual stimuli on components of the event-related potential (ERP) in go/nogo reaction tasks. Biological Psychology 23, 21-38], the go/no-go effect is due to movement-related negative potentials, in particular contralateral negativity, adding with P3 in go trials. To investigate these notions, we studied how CNV, go-P3 and no-go P3 are lateralized at fronto-central sites when the side of the response varies across trials, comparing these effects between hand movements and eye movements and delineating them more precisely for hand movements with multichannel recordings. The go/no-go effect was larger and contralaterally lateralized with hand movements than with eye movements. Dipole analysis dissected its components into a large contribution of the medial cingulate gyrus, into activity of motor areas contralateral to the cued hand and a left-frontal source. Motor-related portions of the effect seemed to build upon and extend motor-related components included in CNV. Results provide support for the notion that the go/no-go effect is related to movement-related potentials. We suggest that go-P3 and no-go P3 are characterized by addition and reduction of motor-related activation to the core P3.     

Functional Differences Between Members of the P300 Complex: P3e and P3b

The main findings of this study bear upon differences in the functional roles of P3b and a shorter latency, more centrally distributed endogenous positive component denoted as P3e. At the present writing, we have observed P3e only in conjunction with P3b. As in the case of P3b, P3e is fully endogenous in that it can be- elicited by omission of a stimulus if stimulus omission conveys relevant information to the subject. It was found that P3e and P3b relate differently to information delivery. Information delivery was manipulated by varying event probabilities and the discriminability of the events. The well known properties of P3b, namely that its amplitude is large when elicited by low probability (high information content) events and is reduced by perceptual difficulty (information loss-equivocation), were replicated in the current study. In contrast to P3b, variation of event probability had no effect upon P3e amplitude, but increased perceptual difficulty markedly reduced P3e amplitude. In addition, two CNV-type negativities were observed in the epochs prior to presentation of the informative signal event: 1) A negativity that was maximal over central scalp related to the subject's prediction that a rare or frequent event would be presented; 2) A negativity that was maximal over occipital scalp related to a stimulus that informed the subject whether the subsequent discrimination of the signal would be easy or difficult. Finally, there was a serendipitous Hading of an apparently new short duration component, tentatively labeled Px, which is elicited by presentation of the signal that informs the subject whether the subsequent discrimination will be easy or difficult.     

P300 topography of amplitude/latency correlations

Summary The correlational association from 19 electrode sites between peak amplitude and latency for the P3(00) event-related brain potential (ERP) for n=80 homogeneous subjects was assessed using a simple auditory discrimination task. The correlation strength varied systematically across scalp topography in different ways for the various ERP components. For the target stimuli, P3 amplitude and latency were negatively correlated and most tightly coupled over the frontal-central and right medial/lateral recording sites. In contrast, the N1 produced negative correlations that were strongest over the left and right central/lateral locations; P2 demonstrated a positive correlation that was strongest frontally and centrally; N2 demonstrated a positive correlations that was strongest over the central and parietal sites. ERPs from the standard stimuli produced generally similar patterns for the P3 and P2 components, with only weak or no reliable effects observed for the N1 and N2 potentials. Taken together, the findings suggest that analysis of amplitude/latency correlational relationships can provide information about ERP component generation. Theoretical implications are discussed.Collaborative studies on the Genetics of Alcoholism (H. Begleiter, SUNY HSCB, Principal Investigator, T. Reich, Washington University, Co-Principal Investigator) includes six different centers where data collection takes place. The six sites and Principal Investigator and Co-Investigators are: Indiana University (J. Nurnberger, Jr., P.M. Conneally); University of Iowa (R. Crow, S. Kuperman); University of California, San Diego and The Scripps Research Institute (M. Schuckit, F.E. Bloom); University of Connecticut (V. Hesselbrock); State University of New York, Health Science Center at Brooklyn (H. Begleiter, B. Porjesz); Washington University in St. Louis (T. Reich, C.R. Cloninger). This national collaborative study is supported by the National Institute on Alcohol Abuse and Alcoholism (NIAAAA) by U.S.P.H.S. grant U10AA08402-07, This paper is publication number NP10292 from The Scripps Research Institute.     

P3a from visual stimuli: typicality,task, and topography

A visual three-stimulus (target, nontarget, standard) paradigm was employed in which subjects responded only to the target. Nontarget stimulus properties were varied systematically to evaluate how stimulus typicality (non-novel vs. novel) across task discrimination (easy vs. difficult) conditions affects P3a scalp topography. Nontarget stimuli consisted of letters, small squares, large squares, and novel patterns; discrimination difficulty between the target and standard was varied across conditions. When the discrimination was easy, P300 amplitude was larger for the target than the nontarget with parietal maximums for both. In contrast, when the discrimination was difficult, nontarget amplitude (P3a) was larger and earlier than the target P300 over the frontal/central electrode sites, whereas target amplitude (P3b) was larger parietally and occurred later. P3a was largest when elicited by either the large square or novel pattern stimuli. The findings suggest that stimulus context as defined by the target/standard discrimination difficulty rather than stimulus novelty determines P3a generation.     

Effects of relevance and response frequency on P3b amplitudes: Review of findings and comparison of hypotheses about the process reflected by P3b

Diverse psychological correlates have been ascribed to “P300,” the conspicuous P3b component of event-related potentials (ERPs) recorded in many laboratory tasks. Traditionally, hypotheses on P3b have conceived of this component being independent from implementing the response to the present stimulus. This has changed in the recent decade when P3b has been related to aspects of the decision process. The present review first focusses on effects of the classic variables stimulus frequency and relevance on P3b amplitude. It turns out that already these effects are related to response requirements because effects of stimulus frequency actually are effects of frequency of response-defined stimulus categories and effects of relevance may be defined as effects of graduating the response requirements. Then, constructs and hypotheses on psychological functions reflected by P3b are evaluated for their abilities in explaining those effects. The tested constructs are information, relevance, and capacity, and the hypotheses are priming, cognitive processing, memory storage, context updating, closure, response facilitation, decision, stimulus–response (S–R) link reactivation, and conscious representations. S–R link reactivation hypothesis performed best, closely followed by memory storage and closure hypotheses. To make further progress, more studies should conduct tests between competing hypotheses.     

Nutritional strategies to optimise cognitive function in the aging brain

Old age is the greatest risk factor for most neurodegenerative diseases. During recent decades there have been major advances in understanding the biology of aging, and the development of nutritional interventions that delay aging including calorie restriction (CR) and intermittent fasting (IF), and chemicals that influence pathways linking nutrition and aging processes. CR influences brain aging in many animal models and recent findings suggest that dietary interventions can influence brain health and dementia in older humans. The role of individual macronutrients in brain aging also has been studied, with conflicting results about the effects of dietary protein and carbohydrates. A new approach known as the Geometric Framework (GF) has been used to unravel the complex interactions between macronutrients (protein, fat, and carbohydrate) and total energy on outcomes such as aging. These studies have shown that low-protein, high-carbohydrate (LPHC) diets are optimal for lifespan in ad libitum fed animals, while total calories have minimal effect once macronutrients are taken into account. One of the primary purposes of this review is to explore the notion that macronutrients may have a more translational potential than CR and IF in humans, and therefore there is a pressing need to use GF to study the impact of diet on brain aging. Furthermore, given the growing recognition of the role of aging biology in dementia, such studies might provide a new approach for dietary interventions for optimizing brain health and preventing dementia in older people.     

Multiple Sources of P3b Associated with Different Types of Information

This experiment investigated how the P3a, P3b, and Slow Wave components of the event-related brain potential (ERP) respond to manipulations of the nature, timing, and extent of information delivery. There were two experiments in which the total amount of task information was distributed between pairs of successive stimuli (S1 and S2) within each trail. The task was to predict the relation between S1 and S2. In Experiment 1, the S1 could resolve no, partial, or all uncertainty with respect to the prediction outcome (correct or incorrect). Each S1 delivered three types of information: 1) outcome information--which resolved the subjects' uncertainty about the correctness of their prediction; 2) procedural information--which resolved uncertainty about how much outcome information would be delivered by S1; and 3) memory information--the identity of S1, which had to be stored for subsequent comparison with S2. In Experiment 2, the activity of these components was contrasted in two conditions in which the S1 delivered either memory information alone or both memory and procedural information. P3a and Slow Wave were sensitive only to outcome information. P3b was sensitive to all three types of information, and its scalp topography varied as a function of the type of information. The topographic variations indicate that P3b is not a unitary phenomenon but rather is a composite of activity arising from multiple intracranial sources of bioelectric activity.     

Event-related brain potentials to violations of arithmetic syntax represented by place value structure

We dissociated ERP markers of semantic (numerical distance) vs. syntactic (place value) incongruence in the domain of arithmetic. Participants verified additions with four-digit numbers. Semantic incongruencies elicited the N400 ERP effect. A centro-parietal (putative P600) effect to place value violations was not related to arithmetic syntax. Rather, this effect was an enlarged P3b reflecting different surprise values of place value vs. non-place value violations. This potential confound should be considered in numerical cognition experiments. The latency of the N400 and P3a effects were differentially affected by place value analysis. The amplitude of the P3a and that of a fronto-central positive effect (FP600) was sensitive to place value analysis and digit content. Results suggest that ERPs can index the syntactical analysis of multi-digit numbers. Both ERP and behavioral data confirmed that multi-digit numbers were decomposed into their constituent digits, rather than evaluated holistically.