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Results for “Contingent Negative Variation”

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PubMed1994

Event-related potentials in humans as indices of access to stored information during sleep.

The even-related potentials are good indices of brain functions during sleep stages. The contingent negative variation (CNV), occurring in the interval between a conditional and a target stimulus, reflects information processing. The emitted potential which occurs when an expected stimulus is omitted reflects the access to a specific memory. During waking, deep slow wave sleep (stage 4) and paradoxical sleep seven subjects were submitted to a CNV paradigm, the target stimulus of which was occasionally omitted. The endogenous components of the evoked potentials induced at Fz, Cz and Pz locations by the auditory stimuli were analysed during the three behavioral stages. During stage 4 they were of largest amplitude and longest latency. These results are discussed in terms of neural excitability. CNV and emitted potentials were observed during waking and paradoxical sleep, but not during stage 4. These results suggest that information processing occurs during paradoxical sleep with access to waking memories during this stage of sleep, whereas information processing is absent during stage 4.

Adult↗
PubMed1995

[Noninvasive study of cortical neuronal mechanism in voluntary movements: role of basal ganglia and cerebellum].

Voluntary movements can be classified into the two categories depending on how those are initiated; ones initiated internally, and others triggered or paced by external stimuli. Central neuronal mechanisms involved in those preparation and execution could be represented by movement-related cortical potentials (MRCP) or Bereitschaftspotential (BP), and contingent negative variation (CNV), respectively. The both potentials, as the field potentials, can be recorded with long time constant, and represent transient changes of the membrane potentials of the cortical neurons. In patients with the lesion at the cerebellar efferent system, the BP disappeared completely whereas the late CNV was normally seen. In patients with parkinsonism, in contrast, the late CNV was significantly smaller in amplitude in severe than in mild symptom group. Recent subdural recording in epilepsy patients demonstrated that the BP and late CNV were commonly generated from the primary and supplementary motor areas, and that late CNV also arose from the frontal association cortices (mesial, basal and lateral prefrontal areas). It is therefore suggested that subcortical generating mechanism is different for the late CNV and BP although both commonly share at least some cortical generators, and that the basal ganglia are most likely responsible for the generation of the late CNV and the cerebellar efferent system for the generation of the BP.

Basal Ganglia↗
PubMed1996

Event-related potentials in Parkinson's disease.

The increasingly recognized occurrence of dementia in Parkinson's disease (PD) has prompted study of cognitive evoked potentials in this disorder. The P300 wave is related to cognitive performance, while the contingent negative variation (CNV) may reflect dopaminergic function. We measured P300 and CNV in 21 nondemented PD patients and compared them to elderly controls. The P300 was recorded from Cz with linked ear reference. 3,000 and 1,000 Hz tones were presented in an 80:20 ratio at 76 dBSL interstimulus interval was 1.1 seconds, and filter bandpass was 1-100 Hz. CNV recording utilized a 2000 Hz tone followed after 1.5 seconds by a light flash and button press, and was recorded from Fz with linked ear reference, 10-second analysis time, and 0.1-20 Hz filter bond pass. N200 and P300 amplitudes were significantly longer and latency significantly lower in PD patients than in controls, and P300 latency was correlated with composite score on cognitive tests. CNV amplitude was significantly reduced in PD patients, but was correlated with measures of motor disability rather than cognition. These findings suggest that bradyphrenia may occur in nondemented PD patients, and that P300 may measure cognitive changes in PD. CNV may be a dopaminergic slow potential and may correlate with motor function in nondemented PD patients.

Aged↗
PubMed1997

[Cognitive impairment in Parkinson's disease--a visual event-related potential study].

The visual event-related potentials(ERPs) in Parkinson's disease(PD) are reviewed. In patients with demented PD, the task-relevant P3(P3b, target P3) latency is significantly prolonged compared with the control, while patients with nondemented PD show inconsistent results, probably due to the difference in experimental procedure or antiparkinsonian medication. The task-irrelevant P3(P3a, nontarget P3) latency under conditions of passive attention is not prolonged in PD regardless of the presence of dementia. The results of P3 amplitudes remain controversial. The N2 latency is delayed compared to the control during the semantic discrimination task, although there is no difference in NA latency. The attenuation in the CNV(contingent negative variation) amplitude is found in PD patients, probably due to the impairment, either in maintaining their attention or preparing the response.

Cognition↗
PubMed1997

[Neurophysiological studies of headaches].

INTRODUCTION AND OBJECTIVE: The diagnosis of headache is based on the clinical criteria suggested by the IHS in 1988. The neurophysiological examinations often used in the study of headache may support the clinical diagnosis and give information as to the prognosis. The objective of this paper is to review the neurophysiological examinations most often used in the clinical and pathological investigation of headache. DEVELOPMENT: As shown by recent studies, the EEG is of little value in the routine evaluation of a patient with headache. However, it may be useful as an exploratory test for underlying pathology in atypical headache or when intra-cranial pathology is suspected. Evoked potentials, when used to study migraine, show absence of Habituation (or Potentiation) in migraine patients. This finding may represent abnormality in the processing of information at a cortical level in these patients. There is a tendency to unify the theory of neurone hypoxia and the absence of Habituation in Migraine as a single hypothesis of pathogenesis. Negative Contingent Variation has proved to be clinically useful to optimize treatment in Migraine. The electromyogram and Muscle Reflexes have been used in the study of Tension Type Headaches, ES2 changes, showing brainstem antinociceptive reflexes support the participation of a central factor in the origin of chronic Tension Headache. CONCLUSION: Neurophysiological tests may be useful in investigation of the pathology of headache since they permit a functional study of many neurone paths and the action of drugs on the central nervous system.

Blinking↗
PubMed1998

Methylphenidate's effects on paired-associate learning and event-related potentials of young adults.

The effects of methylphenidate (0.3 mg/kg) on young adults paired-associate learning (PAL) of consonant-vowel-consonant (CVC) pairs and concomitant event-related potentials were assessed. The stimulant elevated mood and heart rate but did not affect PAL performance. For the first CVC, there were amplitude increases with learning for P3b at Pz, P2 at midline sites, and for a negative slow wave at Cz. For the second CVC, P3b and positive slow wave amplitude declined with learning. Increases in P3b amplitude to the first CVC were attributed to increments in stimulus meaningfulness. Decreases in P3b amplitude to the second CVC were interpreted as resulting from fewer disconfirmed expectations of feedback. The negative slow wave following the first CVC was viewed as a contingent negative variation. Methylphenidate increased parietal P3b amplitude for CVC 2, averaged over learning phases.

Adolescent↗
PubMedDate not supplied

Clinical efficacy and central mechanisms of cyclandelate in migraine: a double-blind placebo-controlled study.

The mechanisms of action of calcium antagonists in the prophylactic treatment of migraine remain unclear. The most likely proposed mechanism seems to be via influence on the central nervous system, but the central effects of calcium entry blockers are insufficiently characterized. The aim of the present study was to investigate the central mechanisms behind the efficacy of cyclandelate in a double-blind placebo-controlled parallel-designed study using the contingent negative variation (CNV), an event-related slow potential for measuring cortical excitability and investigating preparation processes. The CNV recordings were performed in 25 females suffering from migraine without aura before treatment (baseline), after single dose administration of cyclandelate or placebo and after 8 weeks' treatment with cyclandelate (cyclandelate group, no.=15) or placebo (placebo group, no.=10). Cyclandelate reduced significantly the days with migraine and duration of migraine compared to placebo. In the cyclandelate group a significant reduction of all CNV components was observed and the changes in amplitudes compared to baseline were more pronounced after treatment. Placebo reduced the late CNV component only after single dose administration. There were no changes in the early and total CNV. Cyclandelate did not normalize the habituation of the slow negative potential. The results are discussed in terms of the influence of cyclandelate on cortical excitability and of the prevention of cortical spreading depression via antagonistic effect on calcium channels.

Adult↗
PubMedDate not supplied

[Stress and anxiety: what are they?].

Although anxiety and stress were two distinguished concepts, they were used confusedly by medical and psychological talks. Whereas anxiety is currently a well-known psychopathological notion, stress remains blurred and unclear. The aim of the study was of course to exhibit the relationships between stress and anxiety, but also to show by which mechanisms anxiety would have a role in the stress-response modulation. Three groups of subjects, paired in age and sex, were compared: 28 paid controls (13 male) aged 37 +/- 12 years, 25 subjects (12 male) aged 38 +/- 8 who consulted in a framework of CITES Prevert (clinic of stress) but without mental disorders, and 28 subjects (13 male) aged 37 +/- 12, out-patients suffering from anxiety disorders (generalized anxiety disorders according to DSM IV). All of subjects were drug free when examined. They were submitted to auto-evaluation psychological tests: Amiel-Lebigre life events, Spielberger anxiety trait and state, Plutchik and Van Praag depression and finally Chapman anhedonia. After that, two ERPs were recorded, the P300 by using the classical "Oddball experimental paradigm" in auditive modality and the Contingent Negative Variation (CNV) by using a reaction time task with warning stimulus. A close relationships between stress and anxiety could be an evidence as showed by the positive correlations between life events and psychological data (anxiety and depression). In addition, the results displayed correlations between anxiety trait and CNV reaction time (positive correlation) and early P300 (P3a) component amplitude (negative correlation). This could support the hypothesis according to the anxiety would disturb the behavior (slow motor response) and the cognitive processes (attentional changes), and therefore would have a role in the stress-response modulation. Nevertheless, anxiety trait were not correlated to the late P300 component (P3b) amplitude, thus to controlled attention processes. Moreover P3b amplitude were reduced exclusively in subjects who suffered from anxiety disorders. This could mean that anxiety trait would not be solely involved in cognitive changes. Pathological states, as anxiety disorders, could involve another logic of the mental functioning. These results will be discussed according to the cognitive psychology and psychophysiology knowledges.

Adult↗
PubMed1998

[A neurophysiological model of the "paroxysmal brain" (cerebral mechanisms in the genesis of paroxysmal states)].

This paper attempts to elucidate whether common (nonspecific) brain mechanisms are responsible for seizures of epileptic and nonepileptic origin. A comparative study of the following 4 paroxysmal disorders--partial epileptic seizures, paroxysmal dystonia, pseudoseizures and panic attacks was performed. Spontaneous (EEG-mapping) and evoked (contingent negative variation-CNV) bioelectrical activity was measures in all patients several times during interictal periods and after 24-hour sleep deprivation. The main common neurophysiological features of these types of paroxysmal disorders were the increased total power of spontaneous electrical activity, an asymmetric increase of theta-EEC power in the right hemisphere, an increase in total amplitude of CNV. Readiness of the brain for the development of the paroxysms was characterized by dynamic increases of the above parameters of spontaneous and evoked bioelectrical activity.

Brain↗
PubMed1978

A CNV study in a group of patients with traumatic head injuries.

CNVs were studied in a group of 27 subjects with traumatic head injuries followed by protracted coma. Before CNV recording, all patients were subjected to Wechsler-Bellevue Intelligence Scale and to Benton's visual retention test. The findings were compared with those obtained from 80 normal subjects. A statistically significant decrease was observed in the CNV area in the group with traumatic lesions. No correlation could be found between CNV parameters and the results of the mental tests. In 7 of the subjects who presented the highest percentage of errors in Benton's test, a large post-imperative negative variation was observed.

Adolescent↗
PubMed1990

Cognitive determinants of the postimperative negative variation.

This study examined cognitive determinants of the postimperative negative variation (PINV), a slow brain potential observable after the onset of an imperative stimulus in a forewarned reaction time task. Controllability of the aversive imperative stimulus by a motor reaction and predictability of the contingency were varied in a factorial design. The exogenous portion of the slow negative wave was assessed in a passive listening condition using tones of the same quality as the imperative stimuli, but presented without forewarning. Results show that PINV not only occurs when control is absent but also during unpredictably gained control. Similarly, unpredictable lack of control yields a more negative potential than continual helplessness. Negativity elicited by the aversive tone alone was not significantly different from PINV during predictable lack of control. The order of conditions, which was manipulated between groups, did not affect amplitudes. It was concluded that contingency change is a crucial cognitive determinant of the PINV, whereas the effect of lack of control is difficult to differentiate from the sensory influence of the acoustic stimulation.

Adult↗
PubMed1996

Preparation for action: an ERP study about two tasks provoking variability in response speed.

This study focused on the covariation of response speed and event-related potentials during response preparation and on whether these variations can be brought under experimental control. Two S1-S2 choice response tasks with temporal uncertainty were conducted. In Experiment 1, S1 was 100% informative. Fast subjects showed larger P3s with S1 than slow subjects. The terminal CNV (tCNV) increased intraindividually with response speed. In Experiment 2, 50% of S1s were uninformative and the visual display was designed to attract more attention. Effects of information were found on P3 amplitude, on the topography of tCNV, and on the temporal distribution of response times. Interindividual differences disappeared in Experiment 2. The results suggest that group differences in Experiment 1 were due to different strategies of allocating visual attention. Interindividual variations of strategy showed a pattern of effects different from intraindividual variations of efficiency.

Adult↗
PubMed1987

[Changes in slow evoked potentials in depressed patients treated with amitriptyline and oxaprotiline].

Using a simple S1S2-R paradigm, acoustically evoked potentials, CNV, and PINV were recorded in 59 patients with major depressive disorder before and during a 4 week double blind pharmacological treatment with either amitriptyline (AT) or oxaprotiline (OT). In parallel, 30 healthy subjects were investigated 3 times, in identical intervals of 2 weeks. In the depressed state patients exhibited significantly smaller CNVs than the controls. In the AT-group clinical improvement and drug plasma levels of nortriptyline (NT, the principal metabolite of AT and an active antidepressant by itself) were positively related to increases in CNV-area; in the OT-group the reverse was true: increase in CNV-area was related to smaller OT plasma levels and less favourable outcome. The control group displayed a steady decline in CNV area during the 3 test sessions. N1P2 amplitude and PINV were not significantly different between groups and exhibited only minor variations during treatment.

Adult↗