The P300 amplitude of the event-related brain potential indicates changes within a frame-of-reference

The starting point of this study was the fact that investigations in the frame-of-reference research were mostly performed on the behavioural level. The present study aimed at studying behaviour of P300 amplitude of the event-related brain potential in a frame-of-reference investigation. Ten healthy volunteers participated in the investigation. Test material consisted of horizontal bars of different lengths presented successively on a screen. Each bar (serial stimulus) was preceded by a prestimulus (anchor) of constant length. Each serial stimulus was to be evaluated according to a 9 step rating scale. There were no significant differences in the overt length judgements of the serial stimuli depending on the 3 different anchor lengths. However, the mean P300 amplitude increased with growing dissimilarity between the length of the anchor and serial stimulus length. Thus, it is assumed that the adaptation level on the internal dimension of stimulus length, which was assumed to be influenced by the anchor stimuli, led to the different behaviour of P300 amplitude.     

The P300 component of the event-related brain potential in a short-term memory paradigm]

In numerous investigations the P300-component of the event-related-brain-potential (ERP) has proved a valid indicator of memory activities. The present study explores the amplitude of the P300 in an isolated short term memory task with variant difficulties. In two experiments the reproduction of senseless memory material was examined using the categories "syllables" and "consonants". One syllable was thereby synonymous with the so-called "chunk" which represents a subjective unit arising from grouping of memory material. The results show a significant increase in P300-amplitude in a line with memory load in both categories. On the contrary there is no significant difference in the amplitude of P300 between the two categories. These results suggest that the costs for storing one syllable are comparable with those for one consonant.     

Stuttering treatment control using P300 event-related potentials

Positron emission tomography studies during speech have indicated a failure to show the normal activation of auditory cortical areas in stuttering individuals. In the present study, P300 event-related potentials were used to investigate possible effects of behavioral treatment on the pattern of signal amplitude and latency between waves. In order to compare variations in P300 measurements, a control group paired by age and gender to the group of stutterers, was included in the study. Findings suggest that the group of stutterers presented a significant decrease in stuttering severity after the fluency treatment program. Regarding P300 measurements, stutterers and their controls presented results within normal limits in all testing situations and no significant statistical variations between pre and post treatment testing. When comparing individual results between the testing situations, stutterers presented a higher average decrease in wave latency for the right ear following treatment. The results are discussed in light of previous P300 event-related potentials and functional imaging studies with stuttering adults.Educational objectives: The reader will learn about and be able to describe the: (1) use of P300 event-related potentials in the study of stuttering; (2) differences between stuttering and non-stuttering adults; and (3) effects of behavioral fluency treatment on cerebral activity in stuttering speakers.     

The P300 component of the event-related brain potential as an indicator in the study of information processing

Event-related bioelectrical brain activity plays an important role in psychophysiological investigations of mental processes. One of the so-called endogenous components of ERP, the P300, occurring in the time range from 300 ms to 800 ms after stimulus presentation accompanies the selective call on cognitive processing of stimulus information. An overview of some influencing factors and of hypotheses according functional significance of P300 is given. Although functional significance of P300 is only partly known there are interesting possibilities of application, e.g. in Neurology, Psychiatry and Occupational medicine.     

Alcoholism risk and the P300 event-related brain potential: modality, task, and gender effects

The P300 event related potential (ERP) was elicited from young adults at low- (LR) and high-risk (HR) for alcoholism (n = 24/risk group), with equal numbers of male and female subjects employed. The effects of stimulus modality, task difficulty, and gender were assessed with analogous auditory and visual paradigms (tone location/head rotation and tone matching/shape matching). Although task performance was generally comparable across risk groups, LR subjects produced smaller P300 amplitudes than HR subjects for the visual matching tasks. No consistent risk group P300 latency effects were obtained. Gender, task difficulty, and scalp topography differentially modulated the risk group outcomes across paradigms. These findings suggest that P300 amplitude reflects risk-for-alcoholism in male and female young adults, but the specific task conditions and electrode location affect the strength of risk group differences.     

Effects of alcohol sensitivity on P3 event-related potential reactivity to alcohol cues.

Although alcoholics and individuals at risk for alcoholism often show smaller amplitude of the P3 event-related brain potential (ERP), recent data (K. Namkoong, E. Lee, C. H. Lee, B. O. Lee, & S. K. An, 2004) indicate that alcohol-related cues elicit larger P3 amplitude in alcoholics than in controls. Little is known concerning the ERP profiles or alcohol cue reactivity of social drinkers at risk for alcoholism due to low sensitivity to alcohol's effects. Participants differing in alcohol sensitivity viewed images of alcoholic and nonalcoholic beverages while ERPs were recorded and provided information about their alcohol use patterns at baseline and 4 months later. Compared to high-sensitivity participants, those low in sensitivity showed larger P3s to alcohol cues, even when recent alcohol use was statistically controlled for. Moreover, the P3 elicited by alcohol cues predicted alcohol use at follow-up, a finding supporting the idea that P3 amplitude reflects the motivational significance of substance-related cues. These findings point to risk status, not consumption history, as an important predictor of cue reactivity effects.     

Slow movement execution in event-related potentials (P300)

We examined whether slow movement execution has an effect on cognitive and information processing by measuring the P300 component. 8 subjects performed a continuous slow forearm rotational movement using 2 task speeds. Slow (a 30-50% decrease from the subject's Preferred speed) and Very Slow (a 60-80% decrease). The mean coefficient of variation for rotation speed under Very Slow was higher than that under Slow, showing that the subjects found it difficult to perform the Very Slow task smoothly. The EEG score of alpha-1 (8-10 Hz) under Slow Condition was increased significantly more than under the Preferred Condition; however, the increase under Very Slow was small when compared with Preferred. After performing the task. P300 latency under Very Slow increased significantly as compared to that at pretask. Further, P300 amplitude decreased tinder both speed conditions when compared to that at pretask, and a significant decrease was seen under the Slow Condition at Fz, whereas the decrease under the Very Slow Condition was small. These differences indicated that a more complicated neural composition and an increase in subjects' attention might have been involved when the task was performed under the Very Slow Condition. We concluded that slow movement execution may have an influence on cognitive function and may depend on the percentage of decrease from the Preferred speed of the individual.     

Reprint of: stuttering treatment control using P300 event-related potentials

Positron emission tomography studies during speech have indicated a failure to show the normal activation of auditory cortical areas in stuttering individuals. In the present study, P300 event-related potentials were used to investigate possible effects of behavioral treatment on the pattern of signal amplitude and latency between waves. In order to compare variations in P300 measurements, a control group paired by age and gender to the group of stutterers, was included in the study. Findings suggest that the group of stutterers presented a significant decrease in stuttering severity after the fluency treatment program. Regarding P300 measurements, stutterers and their controls presented results within normal limits in all testing situations and no significant statistical variations between pre and post treatment testing. When comparing individual results between the testing situations, stutterers presented a higher average decrease in wave latency for the right ear following treatment. The results are discussed in light of previous P300 event-related potentials and functional imaging studies with stuttering adults.Educational objectives: The reader will learn about and be able to describe the: (1) use of P300 event-related potentials in the study of stuttering; (2) differences between stuttering and non-stuttering adults; and (3) effects of behavioral fluency treatment on cerebral activity in stuttering speakers.     

Effects of negative content on the processing of gender information: An event-related potential study

Previous research on emotion in language has mainly concerned the impact of emotional information on several aspects of lexico-semantic analyses of single words. However, affective influences on morphosyntactic processing are less understood. In the present study, we focused on the impact of negative valence in the processing of gender agreement relations. Event-related potentials (ERPs) were recorded while participants read three-word phrases and performed a syntactic judgment task. Negative and neutral adjectives could agree or disagree in gender with the preceding noun. At an electrophysiological level, the amplitude of a left anterior negativity (LAN) to gender agreement mismatches decreased in negative words, relative to neutral words. The behavioral data suggested that LAN amplitudes might be indexing the processing costs associated with the detection of gender agreement errors, since the detection of gender mismatches resulted in faster and more accurate responses than did the detection of correct gender agreement relations. According to this view, it seems that negative content facilitated the processes implicated in the early detection of gender agreement mismatches. However, gender agreement violations in negative words triggered processes involved in the reanalysis and repair of the syntactic structure, as reflected in larger P600 amplitudes to incorrect than to correct phrases, irrespective of their emotional valence.     

Effects of additional tasks on language perception: an event-related brain potential investigation

The authors investigated effects of task and overlapping processing load on semantic processing. In 3 experiments the brain potential component N400 was elicited by synonymous and nonsynonymous spoken noun pairs that were to be classified according to semantic relatedness. The time course of the N400 component to the nouns was delayed, and its amplitude was reduced when additional tasks had to be performed. The delay increased with temporal overlap and was more pronounced for language-related than for spatial additional tasks. Delays of N400 were also caused by a compatibility manipulation in the additional tasks. Theoretical accounts of the observed interference of overlapping tasks with language perception in terms of attentional shifts were discarded. Explanations in terms of resource sharing and single channel processing are discussed.     

Effects of implicit power motive on the processing of anger faces: An event-related potential study

Implicit motives are one form of motivation that regulates cognitive and emotional processing. In this study, we investigated the impact of implicit power motive (nPower) on the processing of anger faces. Event-related potentials were recorded while high- and low-nPower individuals performed a face version of an emotion Stroop task comprised of anger and neutral faces. It was found that nPower does not modify early perceptual and attentional components (P2 and N2), but a later component is affected. Indeed, power-motivated participants showed enhanced P3/LPPs (Late positive potentials) amplitude compared to low-nPower subjects, in response to anger stimuli. These findings demonstrate that anger faces have greater salience for high-nPower individuals and are subject to a more salient, conscious processing.     

An event-related potential study of the revelation effect

Event-related potentials (ERPs) were recorded during a verbal recognition memory task in order to investigate whether changes in familiarity are part of the explanation for the revelation effect. For half of the test words, participants solved an anagram prior to making the old/new recognition judgment. A revelation effect was obtained: When test words were preceded by the anagram task, a higher probability of an old response was associated with the items than was otherwise the case. The ERPs recorded time-locked to the onset of the test words were separated according to old/new status andthe presence/absence of the anagram task. The ERP index of familiarity was of lower amplitude for both old and new items that were preceded by the anagram task. These findings are consistent with the view that part of the explanation for the revelation effect is a reduction in the familiarity of the critical test items.     

An event-related potential study on the observation of erroneous everyday actions

Recent experiments have demonstrated that error-related negativity (ERN) is not only elicited when people commit errors, but also when they observe others committing errors. The present study investigates whether this observed ERN is also present when participants observe execution errors in an everyday context. Participants observed short sequences of pictures showing steps of everyday actions ending either erroneously or correctly. Participants were instructed to indicate by a delayed response whether the observed action was correctly executed or not. The results showed a large P300 for execution errors compared with the observation of correct sequences, but no ERN activity was found. The present experiment indicates that the detection of execution errors in observation does not rely on the error processing mechanism responsible for generating the ERN. The increased P300 amplitudes suggest a more general monitoring process that signals that the occurrence of unexpected events is involved in the detection of execution errors.     

Methodological issues in event-related brain potential research

Event-related brain potential (ERP) measures have become increasingly popular in experimental psychology and are often employed by researchers who are not formally trained in electrophysiology. A proper application of these measures requires knowledge about the methodological principles and practical issues that are relevant to ERP measurement, analysis, and interpretation. A brief introductory survey of different aspects of ERP methodology (recording, data processing and signal extraction, statistical analysis and interpretation of ERP effects) is presented, and the contributions collected in this special issue on ERP methodology are introduced.