[Variations in the contingent negative variation induced by administration of phenelzine and diazepam in normal adult subjects].
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Brain↗
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Results for “Contingent Negative Variation”
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Influences between the contingent negative variation and the preceding readiness potential.
Contingent negative variation (CNV) is a slow negative shift in the potential, developing in the period of association between the warning and the imperative stimulus. The readiness potential (RP) resembles the CNV in morphology and amplitude and appears before the performance of a voluntary action. When RP precedes the appearance of the warning stimulus, CNV amplitude reaches considerably lower values. This phenomenon could be explained with the assumptions about a common neuronal pool of McAdam (1971) and with the "ceiling" hypothesis of Hamilton et al. (1973). The aim of the present study is to examine the effect of time intervals with different duration between RP and CNV. A decrease in the amplitude of CNV following RP has been found, without statistically significant differences depending on the interval between them. A more significant influence is observed on CNV morphology: in addition to a decrease in the amplitude, there is also a transition from type B to type A CNV when it is preceded by RP. Under conditions of a more complicated task involving combination with CNV, the RP itself shows lower values compared with the case of independent generation. This gives grounds for the conclusion that the complexity and the complex requirements of the task determine the value of the negatively directed slow-potential changes.
Adult↗
Reliability of the contingent negative variation and the auditory evoked potential.
Contingent negative variations (CNVs) composed of 32 trials had a median subject consistency of 0.68 in retests separated from 5 min to 7 days. Hand measurement of the CNV was highly reliable with a median reliability of 0.96. Subject consistencies for the amplitudes and latencies of N1 and P2 components of a auditory evoked potential (AEP) had a median of 0.59 when 265 trials were averaged. These consistencies for N1 and P3 components had a median of 0.45 when only 16 trials were averaged. Median measurement reliabilities for the AEP were 0.92 for amplitudes and 0.66 for latencies.
Adult↗
REM sleep and contingent negative variation development.
Three subjects demonstrated the ability to respond in a contingent negative variation (CNV) paradigm during rapid eye movement (REM) sleep. However, the CNV did not appear as it does in the waking state. This failure of the CNV to develop during REM sleep might be attributed to electrophysiological changes accompanying REM sleep.
Adult↗
Further studies of effects of chlorpromazine on the contingent negative variation.
The effect of 25 mg of chlorpromazine (CPZ) on the contingent negative variation (CNV) at Cz and Oz was studied in nine male subjects. Two kinds of warning stimulus (S1)--imperative stimulus--and motor response (MR) were used. A click as S1 was common to both, while either flashes or electrical stimulation was used as S2. Simultaneously with CNV recording, the reaction time of the finger movement as MR to S2 was measured in five of nine subjects. The results obtained were as follows. 1) CNV amplitudes after CPZ administration were decreased significantly both at Cz and Oz when S2 was flashes and only at Cz when S2 was electrical stimulation. 2) Significant positive correlations of CNV amplitudes between Cz and Oz were found both before and after the drug administration. 3) Reaction times to flashes and electrical stimulation as S2 were not affected by CPZ administration. 4) The reaction time to flashes was significantly shorter than that to electrical stimulation irrespective of pre- and post-administration of CPZ.
Adult↗
Neurophysiological study of 47, XYY and 47, XXY psychopaths: contingent negative variation, evoked potentials and motor nerve conduction.
Neurophysiological investigations-including sensory-evoked responses, contingent negative variation (CNV), and nerve conduction velocities-were done in 11 male polygonosomic patients and in comparison with a control group. Some significant data are reported pointing out differences which may be related to a hypovigil type (47, XYY) and a hypervigil type (47, XXY). The importance of the CNV and conduction velocity as an index of a constitutional minimal brain dysfunction is discussed.
Adult↗
Contingent negative variation and accuracy of time estimation: a study on cats.
Slow cortical potential shifts, similar to the contingent negative variation (CNV) discovered in man, were analysed in cats submitted to a schedule of temporal conditioning. Two situations were compared, according to information delivered during a 7 sec delay: in the first (A), a fixed visual signal appeared on an oscilloscope screen; in the second (B), the signal moved across with time. In both cases, the cat had to press a lever 5-7 sec after signal onset. The CNV recorded during the delay had different amplitudes according to the cortical site involved. It could be dissociated into two components, which showed similar evolutions as a function of experimental conditions. The characteristics of the CNV as a whole varied with temporal parameters. CNV amplitude and time course were related to the accuracy of the cat's responses; prolonged training in unchanged experimental conditions led to a decline in negativity, which seemed to reflect automation of time estimation processes. These data suggest that CNV may be an index of a phase of information processing aimed at constituting internal time bases congruent with a particular situation.
Animals↗
Relationships between the late component of the contingent negative variation and the bereitschaftspotential.
The purpose of this study was to determine whether the late component of the contingent negative variation (CNV) in a S1-S2-respond paradigm shares critical features with the Bereitschaftspotential (BP) prior to self-paced voluntary movements. In a group of 8 subjects, the late CNV and the BP exhibited: (a) similar effects of response speed variation, (b) corresponding influences of subjective factors, and (c) a similar scalp distribution with the exception that the BP was much more lateralized. In contrast, no such relationships were found between early CNV and BP.
Brain↗
The effect of diazepam, chlorpromazine and amobarbital on the contingent negative variation.
The effects of diazepam (5 mg), chlorpromazine (CPZ, 12.5 mg) and amobarbital (100 mg) on the contingent negative variation (CNV) at Cz and Oz were studied in groups of 10 subjects each. Amobarbital and placebo were given by the double-blind crossover method. Two kinds of experimental paradigms were used: Click (warning stimulus, S1)--flashes (imperative stimulus, S2)--and click--electrical stimulation--motor response. The results obtained were as follows; 1) CNV amplitudes were decreased significantly by administration of diazepam only at Cz when S2 was flashes and at both Cz and Oz when S2 was electrical stimulation. 2) CPZ-induced effects were of either augmentation or decrement in CNV amplitudes depending on the subject and on the modality of S2. Involvement of dose-dependent factor was suggested. 3) Amobarbital and placebo did not give any significant changes to the CNV. 4) Significant correlations between CNV amplitudes at Cz and Oz were found before drug administration and even after taking drugs exclusive of diazepam. Its decremental ratio from Cz to Oz was approximately 0.6 to 0.8. The correlation coefficient became to be insignificant after taking diazepam only when S2 was flashes.
Adult↗
The effect of warning stimulus novelty on the P300 and components of the contingent negative variation.
This experiment evaluated the effects of stimulus and response probability on the P300 and components of the contingent negative variation (CNV) in three different reaction tasks. In the first task the warning stimulus (S1) indicated that the imperative stimulus (S2) would require either a left or a right button press response; in the two other tasks the S1 indicated that S2 would either require a button press response or not. The a priori probability of S1 and the response to S2 were independently varied. The results show that a novel S1 significantly increased the amplitude and latency of the P300 and early CNV component: the late CNV component, however, increased significantly when a motor response to S2 was required. Early and late CNV components also differed in midline distribution. It is concluded that the early CNV can be viewed as the slow wave part of the event-related potential to S1, while the late CNV is an event preceding shift that strongly relates to the motor requirements of S2. It is finally suggested that both the P300 and early CNV reflect an orienting response to S1.
Acoustic Stimulation↗
Study of contingent negative variation and the post-imperative wave in the presence of interference.
The aim of this investigation was to study ways of inducing prolonged contingent negative variations (CNV) in human subjects. Fourteen subjects underwent the following experimental procedure: 1st day: 2 CNVs in control conditions were recorded (16 successive trials, each with standard S1--S2 paradigm). 2nd day: 5 successive CNVs were recorded:(1) control; (2) labyrinthine stimulation before 1st, 5th, 9th and 13th trials with simple mental calculation performed between S1 and S2, i.e. during CNV; (3) mental calculation only; (4) labyrinthine stimulation only; (5) control. None of the three interference situations caused any significant changes in the mean and maximal CNV amplitudes measured between S1 and S2. On the other hand, the post-imperative part of the CNV was significantly (P less than 0.025) prolonged but only in the situation where 2 types of interference were applied at the same time. This increase disappeared with removal of the double interference. This change, which matches that observed spontaneously and reversibly in certain mental patients in the acute phase of their illness, seems to reflect a transient alteration of the psychophysiological state of the subject. The possibility of inducing these changes in a normal subject could serve as a means of determining the individual threshold of stress.
Adult↗
Dissociation between motor potential and contingent negative variation after lesions of some basal ganglia in man: electrophysiological study of torticollis.
Studied slow cortical potentials associated with voluntary movements ("readiness potential", RP and "motor potential", MP) and discrimination tasks (contingent negative variation", CNV, "expectancy wave", EW) in 11 normal subjects and 11 patients with torticollis (every person going through 2 experimental sessions). The following was found: 1. In torticollis-patients, the RP appeared as a complex, irregular wave with low--voltage, ataxic course. 2. The mean amplitude of the RP was significantly lower in the torticollis-group than in the control group. 3. The mean amplitude of the late positive component P2 of the MP was also significantly lower in torticollis-patients than in controls. 4. The CNV showed a high-voltage course in patients with torticollis. 5. The mean amplitude of the CNV was significantly higher in torticollis--patients than in controls. 6. The mean amplitude of the late positive component P2 after the resolution of the discrimination task was also higher in the torticollis--group than in the control group, but the difference did not reach the level of significance.--This marked dissociation between the adynamic RP-MP field generators and the very responsive CNV field generators is being interpreted partly as an electrophysiological symptom of impairment in programming and performance of sequential motor acts (in the case of the RP-MP), partly as a disruption of the control of emotional and affective processes, as well as non-specific (extralemniscal) afferences (in the case of the CNV) resulting from a basal ganglia lesion in torticollis.
Adolescent↗
Characteristics of the contingent negative variation in patients suffering from specific phobias.
The essential clinical feature of phobic neurosis is the anticipatory fear of certain objects and situations. Since an important factor in the generation of the contingent negative variation (CNV) is the anticipation of the imperative stimulus, records of CNVs were used as an indicator of electrocortical activity in a group of 14 patients suffering from specific phobias. After clinical evaluation, a CNV to a picture of a nondisturbing object was obtained. The amplitude of the CNV and duration of the PINV (postimperative negative variation) were taken as reference values against which response to the phobic objects were evaluated. Reaction time was automatically measured between the period of S2 and the button press. Significant differences, viz., larger CNV amplitude, longer PINV duration, and shorter reaction time, were found with phobogenic than with nondisturbing stimuli. After behavioral recovery with behavior therapy, no differences were noted in the CNVs obtained with the presentation of non-disturbing and the ones that were phobogenic stimuli. The significance of the results for an understanding of phobic neurosis and behavior therapy are discussed.
Adult↗
Contingent negative variation and alpha attenuation responses in children with different abilities to concentrate.
In three paralleled groups, each of seven children (age, 11 years) with reliable high, average and low ability to concentrate, measured by psychological tests, the contingent negative variation (CNV) and the concomitant alpha attenuation responses were studied in warned reaction time experiments. Stimuli were tone (S1) and patterned light (S2). In half of the trials, S2 was a square, in the other half a triagle, stimuli being projected in random order onto the fixation point. In two experiments the children had to react (a) to each type of S2, and (b) selectively to one type of S2. Significant group differences were found. In comparison to the children with low ability to concentrate, the children with average and especially those with high ability to concentrate showed: (1) stronger central occipital alpha attenuation responses to the warning stimulus, but no differences in the early CNVs; (2) more occipital alpha reduction and enhanced development of central negativity before the imperative stimulus; (3) task-specific modulation of these responses, i.e. larger pre-S2 rise in negativity in the simple reaction task, and stronger pre-S2 reduction of alpha amplitudes in the discriminative reaction task.
Alpha Rhythm↗
[The P 300 wave: psychophysiological aspects and correlations with contingent negative variation (CNV)].
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Acoustic Stimulation↗
[The importance of the "contingent negative variation" (CNV) for audiometry (author's transl)].
Previous proofs of "central processes" in hearing were based on the determination of the late "auditory evoked potentials" (AEP's: 50--300 ms) in EEG. The appearance of AEP's in different sleep stages raises the question, if the AEP actually conscious hearing. Since the discovery of the "Contingent Negative Variation" (CNV), as a potential depending on conscious and cognitive factors, an appropriate "instrument" is available to solve this problem. Using the CNV-technique three proofs of central auditory perception are described and discussed: a) "The objective proof of the perception of pure-tones", useful for threshold determination, test in the case of simulation and central hearing disorders. b) "The objective proof of the perception of stimulus-changes", useful for exact determination of differential thresholds for frequencies or intensities. c) "The objective speech audiometry", proof of speech comprehension, useful in case of aphasia and simulation.
Auditory Perception↗
The contingent negative variation during a memory retrieval task.
Evoked potentials were recorded from the human scalp during performance of a memory retrieval task modeled after a paradigm originated by Sternberg (1966). Subjects were required to decide whether a probe digit was contained in a series of one to four target digits presented a few seconds before. The amplitude of the contingent negative variation (CNV) preceding the probe digit and the speed of CNV resolution after the probe varied as a function of target set size. CNV amplitude was greatest when the set size was one. The smaller the set size, the more positive the evoked potential 300 msec after the probe, regardless of whether a motor response was required.
Adult↗
S1 modality effects on the two components of the contingent negative variation (CNV) [proceedings].
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Acoustic Stimulation↗