Functionally independent components of the late positive event-related potential during visual spatial attention.
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Human event-related potentials (ERPs) were recorded from 10 subjects presented with visual target and nontarget stimuli at five screen locations and responding to targets presented at one of the locations. The late positive response complexes of 25-75 ERP average waveforms from the two task conditions were simultaneously analyzed with Independent Component Analysis, a new computational method for blindly separating linearly mixed signals. Three spatially fixed, temporally independent, behaviorally relevant, and physiologically plausible components were identified without reference to peaks in single-channel waveforms. A novel frontoparietal component (P3f) began at approximately 140 msec and peaked, in faster responders, at the onset of the motor command. The scalp distribution of P3f appeared consistent with brain regions activated during spatial orienting in functional imaging experiments. A longer-latency large component (P3b), positive over parietal cortex, was followed by a postmotor potential (Pmp) component that peaked 200 msec after the button press and reversed polarity near the central sulcus. A fourth component associated with a left frontocentral nontarget positivity (Pnt) was evoked primarily by target-like distractors presented in the attended location. When no distractors were presented, responses of five faster-responding subjects contained largest P3f and smallest Pmp components; when distractors were included, a Pmp component appeared only in responses of the five slower-responding subjects. Direct relationships between component amplitudes, latencies, and behavioral responses, plus similarities between component scalp distributions and regional activations reported in functional brain imaging experiments suggest that P3f, Pmp, and Pnt measure the time course and strength of functionally distinct brain processes. (+info)
Auditory event-related potentials (P300) in partial and generalized epileptic patients.
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We evaluated the P300 components of event-related potentials (ERP) in 64 cryptogenic partial epilepsy (CPE) patients, and 52 idiopathic generalized epilepsy (IGE) patients as well as in their age-matched control groups. The P200, N200 and P300 latencies recorded from Cz were significantly longer in CPE patients compared with those of their control group (P = 0.0371, P = 0.0092 and P = 0.0405, respectively). The P200 and N200 latencies recorded from Fz were significantly longer than in their control group (P = 0.0448 and P = 0.0107) while the prolongation in the P300 latencies was not found to be statistically significant (P = 0.0733). All latencies were longer in IGE patients, and the amplitudes of the N200/P300 components of ERP were lower in both epileptic groups compared with their control groups, but these differences were not significant. The prolongation of the P300 latencies was not correlated with the type or serum level of antiepileptic drug or seizure control. Our findings suggest that the prolongation of the P300 latency of ERP is related to the type of epilepsy. (+info)
Identification of neural circuits underlying P300 abnormalities in schizophrenia.
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Event-related potentials (ERPs) provide a noninvasive method to evaluate neural activation and cognitive processes in schizophrenia. The pathophysiological significance of these findings would be greatly enhanced if scalp-recorded ERP abnormalities could be related to specific neural circuits and/or regions of the brain. Using quantitative approaches in which scalp-recorded ERP components are correlated with underlying neuroanatomy in schizophrenia, we focused on biophysical and statistical procedures (partial least squares) to relate the auditory P300 component to anatomic measures obtained from quantitative magnetic resonance imaging. These findings are consistent with other evidence that temporal lobe structures contribute to the generation of the scalp-recorded P300 component and that P300 amplitude asymmetry over temporal recording sites on the scalp may reflect anatomic asymmetries in the volume of the superior temporal gyrus in schizophrenia. (+info)
Subtypes of family history and conduct disorder: effects on P300 during the stroop test.
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The goal of the present study was to identify neurophysiological differences associated with a family history of substance dependence, and its subtypes (paternal alcohol, cocaine, or opiate dependence), and with conduct disorder, and its subtypes (aggression, deceitfulness/theft, and rules violations). P300 event-related brain potentials were recorded from 210 males and females, aged 15-20 years while they performed the Stroop color-word compatibility test. Analyses revealed no significant effects of familial substance dependence on P300. However, an elevated number of conduct disorder problems was associated with a statistically significant reduction in P300 amplitude. The P300 amplitude reduction was related to the severity of the "rules violation" subtype, but was unrelated to aggression or deceitfulness and theft. It is concluded that conduct disorder can explain many of the P300 findings previously attributed to a family history of alcohol dependence. Furthermore, it appears that conduct disorder may be a heterogenous classification comprised of neurophysiologically different subtypes. (+info)
ESBRA-Nordmann 1998 Award Lecture: Visual P3 as a potential vulnerability marker of alcoholism: evidence from the Amsterdam study of children of alcoholics. European Society for Biomedical Research on Alcoholism.
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Recent data from the Amsterdam Study of Children of Alcoholics add to the evidence for considering the P300 or P3 component of the event-related potential (ERP) as a potential vulnerability marker of alcoholism. In this study, multi-channel ERPs were recorded from 7- to 18-year-old children of alcoholics (COAs) and age- and sex-matched low-risk controls using several experimental paradigms, including a visual novelty oddball task and a visual selective attention task. The results indicated that differences between COAs and controls in the visual P3 amplitude: (1) can be elicited both actively by task-relevant target stimuli and passively by irrelevant novel stimuli; (2) are a function of both the attentional relevance and the target properties of the eliciting stimulus; (3) are mediated by multiple brain generators, rather than by a single generator; (4) originate from a difference in the strength, rather than in the spatial configuration, of the underlying brain generators; (5) cannot be accounted for by differences in visual attention-related earlier occurring ERP components; and (6) can be moderated by current behavioural and emotional problems, general intellectual ability, and socio-economic background. These findings support the notion that a relatively small visual P3 amplitude in COAs reflects heritable biases in attention and information processing that are related to their increased vulnerability to alcoholism. (+info)
Joint multipoint linkage analysis of multivariate qualitative and quantitative traits. II. Alcoholism and event-related potentials.
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The availability of robust quantitative biological markers that are correlated with qualitative psychiatric phenotypes can potentially improve the power of linkage methods to detect quantitative-trait loci influencing psychiatric disorders. We apply a variance-component method for joint multipoint linkage analysis of multivariate discrete and continuous traits to the extended pedigree data from the Collaborative Study on the Genetics of Alcoholism, in a bivariate analysis of qualitative alcoholism phenotypes and quantitative event-related potentials. Joint consideration of the DSM-IV diagnosis of alcoholism and the amplitude of the P300 component of the Cz event-related potential significantly increases the evidence for linkage of these traits to a chromosome 4 region near the class I alcohol dehydrogenase locus ADH3. A likelihood-ratio test for complete pleiotropy is significant, suggesting that the same quantitative-trait locus influences both risk of alcoholism and the amplitude of the P300 component. (+info)
Feedback processing as parallel task in P300 conditioning.
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Previous reports on conditioning P300 amplitude indicated that downtraining produced a stronger effect than uptraining. This asymmetry can be due to the effect of drain on processing resources of the brain produced by the attempts to use feedback information (parallel task effect). Such a drain should reduce P300 amplitude regardless of the direction of training. The aim of the experiment was to demonstrate this effect. Event-related potentials (ERPs) evoked by light stimuli in a standard odd-ball procedure were recorded from Fz, Cz and Pz scalp sites. Subjects were instructed to enlarge or to reduce the P300 amplitude. The first 30 presentations of the target stimulus were analyzed during which the effect of learning should be negligible and processing of feedback information should be intensive. ERPs recorded during uptraining and downtraining were compared with the no-feedback recordings. As predicted, downtraining significantly reduced the P300 amplitude even in the first session of learning. Unexpectedly, uptraining recordings did not differ from no-feedback ERPs but differed significantly from downtraining waves. Such results support the prediction that feedback procedures involve a number of processes that alter the P300 amplitude even before the effects of learning can be expected. But if the hypothesis of the parallel task is to be accepted there must be another instantaneous process that compensates for P300 amplitude reduction during uptraining. (+info)
The functional neuroanatomy of target detection: an fMRI study of visual and auditory oddball tasks.
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The neuronal response patterns that are required for an adequate behavioural reaction to subjectively relevant changes in the environment are commonly studied by means of oddball paradigms, in which occasional 'target' stimuli have to be detected in a train of frequent 'non-target' stimuli. The detection of such task-relevant stimuli is accompanied by a parietocentral positive component of the event-related potential, the P300. We performed EEG recordings of visual and auditory event-related potentials and functional magnetic resonance imaging (fMRI) when healthy subjects performed an oddball task. Significant increases in fMRI signal for target versus non-target conditions were observed in the supramarginal gyrus, frontal operculum and insular cortex bilaterally, and in further circumscribed parietal and frontal regions. These effects were consistent over various stimulation and response modalities and can be regarded as specific for target detection in both the auditory and the visual modality. These results therefore contribute to the understanding of the target detection network in human cerebral cortex and impose constraints on attempts at localizing the neuronal P300 generator. This is of importance both from a neurobiological perspective and because of the widespread application of the physiological correlates of target detection in clinical P300 studies. (+info)