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Results for “Contingent Negative Variation”

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PubMed1980

Combined effects of alcohol and sleep deprivation in normal young adults.

The effect of combining sleep deprivation and moderate alcohol consumption in male college students differed from the effects of each treatment alone. Following either alcohol or sleep deprivation, there was mild performance impairment, decreased alertness and reduced amplitude and increased latency of cortical evoked potential (EP) components. Heart rate increased after alcohol and anxiety increased after sleep deprivation. When alcohol and sleep deprivation were combined, antagonistic effects were found for most measures (reaction time, heart rate, alertness, anxiety, latency of early EP components), but synergistic effects also occurred (performance accuracy, latency of late EP components). These effects were found in a double-blind experiment using 24 subjects. The experimental treatments were alcohol doses of 0, 0.45 and 0.90 ml/kg of 95% ethanol and 0 and 26 h of sleep deprivation.

Adult↗
PubMed1976

Variability of cortical evoked responses in man related to slow wave activity.

Acoustically evoked responses were recorded from subdural and intracerebral electrodes chronically implanted in man. It was found that during slow wave activity especially the negative component at about 100 ms latency varies in form and amplitude. If the stimuli were presented during increasing cortical negativity, the amplitude of the 100 ms component of the evoked responses was generally larger than in the case of stimuli presented during decreasing negativity.

Cerebral Cortex↗
PubMed1993

Self-regulation of slow cortical potentials in psychiatric patients: alcohol dependency.

Ten unmediated alcohol-dependent male inpatients participated in a Slow Cortical Potential (SCP) self-regulation task utilizing biofeedback and instrumental conditioning. These patients were hospitalized for treatment of alcohol dependency after chronic abuse of alcoholic beverages. Somatic withdrawal symptomatology had occurred recently and the patients were free of any withdrawal symptoms of the autonomic nervous system. Immediately after hospitalization patients were unable to control their SCPs without the reinforcement of immediate feedback across 4 sessions. Seven patients participated in a fifth session an average of 4 months later. Six out of these 7 patients had not had a relapse at the follow-up. In the fifth session these patients were immediately able to differentiate between the required negativity and negativity suppression, whereas the seventh patient, who had relapsed, was unable to control his brain potentials successfully. Results are further evidence that some of the frontocortical dysfunctions in alcohol-dependent patients are reversible. This could covary with a morphological restitution of the cortex.

Adult↗
PubMed1994

A spatiotemporal dipole model of the stimulus preceding negativity (SPN) prior to feedback stimuli.

Ten subjects performed a time production task, in which they were instructed to press a button four seconds after the presentation of an auditory stimulus. Two seconds after the button press they received either auditory or visual feedback on the temporal accuracy of their response. In such a paradigm negative slow brain potentials can be recorded preceding the response (Movement Preceding Negativity, MPN) as well as preceding the feedback stimulus (Stimulus Preceding Negativity, SPN). Spatiotemporal dipole modelling is used to gain insight in the possible generators of MPN and SPN. From the models it follows that the MPN can be described by one contralateral radial dipole and a bilateral pair of tangential dipoles. All three dipoles are located near central electrode positions, so the generators of the MPN probably reside within the motor cortex. The SPN is modelled by a bilateral frontotemporal pair of dipoles, hypothetically representing activation of the Insulae Reili. The insular cortex is involved in the processing of affective-motivational input, such as carried by the feedback in the present paradigm. However, processing of the information content of the feedback stimulus might by itself also activate the frontal cortex. Both the response and the feedback stimulus are followed by a positive peak, which can be described by the same deep posterior dipole. Both peaks probably represent a P3, which is related to context updating.

Adult↗
PubMed1994

Cortical magnetic and electric fields associated with voluntary finger movements.

Multichannel recordings of both movement-related magnetic fields (MRMFs) and movement-related cortical potentials (MRCPs) were simultaneously recorded in association with voluntary unilateral self-paced index finger abduction movement in two normal volunteers. 1) Slow magnetic field (readiness field; RF) can be detected several hundred msec before the movement onset, and its field distribution indicates the existence of the largest generator source over the contralateral primary motor area. Taken together with the vertex-maximal Bereitschaftspotential which corresponds to the earlier part of the RF, the complexity of this magnetic field suggested by relatively low correlation value in single dipole model indicates the co-activation of other underlying generators besides this largest dipole. 2) The utilization of MRMF with MRCP facilitates the separation of two distinct electrophysiological events in proximity to the movement onset, which are difficult to be determined by the technique of MRCP only. Those are the motor field (MF) and the movement evoked field I (MEFI) in MRMF, and the parietal peak motor potential (ppMP) and the frontal peak motor potential (fpMP) in MRCP, which occur approximately 20 and 100 msec after EMG onset, respectively. These two subcomponents may imply the culmination of motor cortex and sensory feedback activation, respectively. Combined study of MRMF and MRCP will provide better definition of cortical events related to voluntary movement than the study of either modality alone.

Adult↗
PubMed1982

Slow brain potentials after withdrawal of control.

The present experiment was designed to replicate and extend the previous finding of an increased postimperative negative slow brain potential shift (PINV) in healthy subjects following an unexpected change from the condition of control over an aversive imperative stimulus to that of loss of control. Two groups of 16 male students each participated in a constant-foreperiod reaction time paradigm with two warning stimuli (WS), each of 6 s duration, followed by two imperative stimuli (IS) of either aversive (loud noise) or neutral (soft tone) quality. The experimental subjects could terminate each IS by pressing a microswitch within 300 ms of IS-onset. After they had experienced this contingency for 40 trials, control was withdrawn in that the IS lasted for 5 s during another 40-trial block, irrespective of the actual motor response of the subject. The yoked control subjects received the same stimuli and performed the same motor response as the experimental subjects, but experienced no contingency between response and IS-termination. EEGs were recorded monopolarly from Fz, Cz, and Pz. In response to the unexpectedly uncontrollable aversive IS, the experimental subjects showed a pronounced PINV over frontal areas, while no comparable PINV developed in yoked controls. Experimental subjects showed no PINV during the first trial block (control conditions), and in response to the neutral uncontrollable IS. Statistical analyses of principle components documented that the PINV can be considered an independent endogenous component.

Avoidance Learning↗
PubMed1995

Brain electrical activity (quantitative EEG and bit-mapping neurocognitive CNV components), psychometrics and clinical findings in presenile subjects with initial mild cognitive decline or probable Alzheimer-type dementia.

Clinical, neuropsychological and neuropsychophysiological data (Q-EEG, ERPs and CNV/RT activity) were obtained from 24 patients who had more or less severe presenile primary cognitive decline without depression, and compared with similar data from 10 age-matched healthy volunteers (mean age, 59.4 years). All of the patients (15 M and 9 F; mean age 59.6 years) were selected according to the DSM III-R, ICD-10 and NINCDS-ADRDA criteria and underwent CT and MRI scanning, in addition to a standard clinical examination, a battery of psychometric tests, spectral EEG, and bit-mapped CNV complex and RT to S2 analyses. Twelve of the 24 patients presented an initial presenile idiopathic cognitive decline (PICD) but did not wholly fulfil the clinical and neuropsychological criteria for primary dementia or for a diagnosis of probable AD; the remaining 12 patients showed characteristic clinical signs and symptoms of a very probable early stage of presenile Alzheimer-type dementia (PAD). ANOVA, correlational and discriminant analyses of the neuropsychological test scores, and the neurophysiological and RT to S2 data revealed 22 highest-ranked between-group discriminant factors (all with a significance level of p < 0.01). The conclusive discriminant analysis retained 13 of these factors as final canonical functions, and these showed a 97% grouping accuracy (33 of the 34 subjects examined); the same percentage of correct classifications was also achieved using only the 15 best indicators in the group of CNV/RT findings. Using both of these sets of highest-ranked discriminators, all of the normal subjects and all of the PAD patients were correctly classified; only 1 PICD patient was misclassified as normal when the first group of 13 factors was used, and another PICD patient was misclassified as PAD using the second group of 15 factors. Our findings suggest that, providing they are correctly performed and interpreted, these non-invasive techniques may be an important tool for identifying incipient stages of presenile Alzheimer-type dementia.

Aged↗
PubMed1990

Auditory event-related potentials and reaction times during simple sensorymotor tasks in subjects with sickle cell disease and related hemoglobinopathies.

40 subjects of both sexes assigned to five groups of 8: healthy students, homozygous sicklemics, hemoglobin SC sicklemics, sickle cell Bo thalassemics, and sickle cell B+ thalassemics were subjected to 1/simple auditory stimuli; 2/paired auditory stimuli. The subjects were asked to respond quickly, by pressing a push button on detection of the simple stimulus or the unconditional stimulus of paired stimuli. A subsequent increase in reaction times and a reduction in event-related potential component amplitudes were obvious in major (SS and SC) sicklemics compared to controls and sickle cell B thalassemics. Between simple and paired auditory conditions, reaction times were more increased in sicklemics than in controls. These findings suggest that impairment of attentiveness, performance and cognitive capability in sicklemics is a function of sickle cell anemia severity.

Adolescent↗
PubMedDate not supplied

Possible mechanisms of delay in initiation of voluntary movements.

Studies were made of psychomotor responses and accompanying cortical evoked potentials in healthy subjects and patients with Parkinson's disease. Measurements showed that delays in a variety of psychomotor responses resulted from delays in movement initiation. The frontal regions showed increases in the N2 component of evoked potentials and delayed development of P3 waves. It is suggested that delayed initiation of movements in patients with Parkinson's disease might be associated with strengthening of frontal inhibitory systems, preventing the onset of movements.

Contingent Negative Variation↗
PubMedDate not supplied

Event-related brain potentials elicited by rhyming and non-rhyming pictures differentiate subgroups of reading disabled adolescents.

Event-related brain potentials were recorded while disabled adolescent subjects read and judged whether two sequentially presented pictures had names that rhymed. Subjects with relatively good phonetic skills displayed an N400 priming effect, i.e., a significant reduction in the amplitude of the negative peak, occurring approximately 400 msec post-stimulus, for pictures with names that rhymed with preceding pictures as compared with pictures that had names that did not rhyme with the prime. No such effect was evident for subjects with relatively poor phonetic skills. This lack of an N400 priming effect provides evidence for a reduction in neural capacity and/or activation during phonological processing in the subjects with poor phonological skills. Demonstrating the N400 priming effect to be stronger in one group of reading disabled subjects, compared to another, supports the position that specific subtypes of reading disability exist. In addition to the stronger N400 priming effect, the phonetically stronger group also exhibited an enhanced negativity, from 700 to 1,000 msec after target stimulus onset, compared to phonetically inferior subjects. This finding replicates earlier work and possibly reflects a higher level of confidence in the group with better phonetic skills.

Adolescent↗
PubMed1997

Topography and dipole analysis of reafferent electrical brain activity following the Bereitschaftspotential.

The cerebral events related to limb movements can be studied noninvasively with the method of evoked potentials. In this study, a brain potential is analysed that follows the onset of a simple finger movement. Because this potential occurred after active as well as after passive movements, its previously alleged reafferent somatosensory nature is confirmed in this study. Detailed topographic analysis revealed that this potential has the same polarity and merges with the preceeding Bereitschaftspotential (BP; in the active movement) at central electrodes, whereas at parietal electrodes polarity is opposite to the BP. In individual subjects, the maximum of the BP and the peak of the reafferent potential are separated by a small gap, previously described as pre-motion positivity. A comparison with the N20 potential of the electrically evoked somatosensory potential showed similar potential topography, albeit opposite polarity. The dipole analysis supported the view that the reafferent and the electrically evoked potentials are likely to arise from the same cortical area, namely the primary somatosensory cortex.

Adult↗
PubMed2004

[Mismatch negativity in schizophrenia research. An indicator of early processing disorders of acoustic information].

Mismatch negativity (MMN) represents an event-related component of the auditory evoked potentials at about 100-250 ms, evoked by discernible changes in an ongoing uniform acoustic stimulation. The current paper reviews all recently published MMN studies in the field of schizophrenia research. A reduced MMN in schizophrenic patients is found in the majority of the studies. This deficit is likely to be related to the disorder, since antipsychotic medication seems to have little influence on these results. Interestingly, a reduced MMN is also found in first-degree relatives of patients. Clear evidence for a hemispheric lateralization of the MMN reduction in schizophrenic patients is lacking. A hypofunction of the N-methyl-D-aspartate (NMDA) receptor is discussed as a possible explanation of this deficit.

Auditory Perceptual Disorders↗
PubMed2006

Sensorimotor effects of pergolide, a dopamine agonist, in healthy subjects: a lateralized readiness potential study.

OBJECTIVE: The major purpose of the present study was to further elucidate dopaminergic modulation of sensorimotor processing in healthy human subjects. MATERIALS AND METHODS: 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. OBSERVATIONS: 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. CONCLUSION: 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.

Adult↗