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PubMed1975

The impact of warning signal intensity on reaction time and components of the contingent negative variation.

Slow EEG potentials were recorded during performance of a simple reaction task in which warning signal intensity was varied from trial to trial under foreperiod durations of 1, 3 and 8 sec. As shown by speed of reaction, the warning signal had an activating effect which increased with its intensity and decreased with foreperiod duration. This effect was related to the amplitude of a slow potential which appears in the EEG shortly after presentation of the warning signal. This potential is interpreted as a component of the orienting response regulating sensitivity to subsequent stimulation, so that reaction time is affected through change in the effective intensity of the imperative signal.

Acoustic Stimulation↗
PubMed1981

[Concerning the interpretation of the contingent negative variation in psychiatry (author's transl)].

After a review of the literature stressing the biological factors underlying CNV genesis, the author sets up a tentative biological model of CNV, based on the neurophysiological and neurochemical findings of Skinner and Yingling (1977) and Marczynski (1978). In terms of balance between excitatory and inhibitory processes this model encompasses different CNV abnormalities in amplitude or duration frequently observed in mental pathology. The interest of such a model lies in the physiopathologic and therapeutic hypotheses it may lead to. In this respect, CNVs of prolonged duration, which would reflect a catecholaminergic hyperactivity, could constitute an indication for treatment by neuroleptics and/or benzodiazepines. CNVs with a weak amplitude would rather invite one to prescribe antidepressant drugs.

Acetylcholine↗
PubMed1976

Effects of changes in carbon dioxide tension in abnormally prolonged contingent negative variation (CNV).

The effects of changes in pCO2 in the development and resolution of normal (return to base line within 2 sec after S2) and abnormal (return to base line in more than 2 sec after S2) CNVs were studied. Decreased pCO2 produced by hyperventilation induced a significant reduction in the duration of the post-imperative negative variation (PINV) without significantly affecting the amplitude of the CNV. Increased pCO2, by inhalation of 5% CO2, on the contrary, produced prolongation of the PINV in two subjects. Control subjects with normal CNVs did not show significant changes in the amplitude or in the duration of the CNV wave when pCO2 was altered. The results are discussed in terms of the possible independence and higher sensitivity to metabolic changes of the PINV brain generators compared with the generators of the CNV wave per se.

Administration, Intranasal↗
PubMed1979

Contingent negative variation and evoked potential amplitude as a function of inspired nitrous oxide concentration.

Nine subjects were given to breath 10%, 20%, 30% and 40% nitrous oxide in oxygen. The inhaled gas concentrations were monitored by a mass spectrograph. At each gas concentration the CNV was measured in a standard long S1-S2 CNV paradigm to a click and tone with a mandatory button press at S2. The results confirmed the previous observations of Lader and Morris (1974) that the cortical evoked potential decreases rapidly with increasing concentrations of nitrous oxide. The CNV, however, against prediction remains surprisingly well preserved up to the borders of unconsciousness. In this situation there is little correlation between CNV amplitude and attention, arousal or reaction time.

Adult↗
PubMed1984

Early and late components of the contingent negative variation prior to manual and speech responses in stutterers and non-stutterers.

The early and late components of the CNV were measured in 18 stutterers and 18 non-stutterers, all dextral, prior to a manual and 3 speech tasks. It was hypothesized that, due to a proposed deficit in articulatory timing, prior to the more complex speech tasks, stutterers would show reduced late CNV amplitudes over Broca's area when compared to the non-stutterers. This hypothesis was not confirmed. In both groups, there was a finding of greater late CNV activity over the right hemisphere prior to speech responses. Explanations for this finding in terms of (a) CNV polarity, and (b) right hemisphere involvement in the speech responses used, are proposed. It is suggested that attention be paid to the nature of the response when attempting to record slow brain potentials prior to speech.

Adult↗
PubMed1976

The contingent negative variation and psychological findings in chronic hepatic encephalopathy.

Early diagnosis of chronic hepatic encephalopathy (CHE) in the latent stage before the appearance of clinical signs, should reduce both morbidity and mortality as deterioration is often preventable by treatment. Since existing diagnostic procedures are inadequate, we have investigated a test in which morphine is used as a provocative agent and any resulting change in cerebral function assessed by measurement of the CNV in conjuction with a psychological trail test. Twenty six patients were studied, 6 of whom had clinically overt CHE. A significant correlation (P less than 0.05) between the change in CNV amplitude with morphine and the initial CNV amplitude, consistent with the theoretical model of Tecce (1972), was found. However, the CNV and trail test results taken as a whole did not allow even those patients with overt CHE to be distinguished and we conclude that it is unlikely that differing degrees of latent CHE could be detected.

Chronic Disease↗
PubMed1978

The effects of a depressant and a stimulant drug on the contingent negative variation.

Three groups, each comprising eight subjects, were twice tested with an interval of one week: one group receiving 10 and 20 mg chlordiazepoxide, another group receiving 150 and 300 mg caffeine and a control group receiving placebo and 'no-drug' treatment. During each session the CNV was determined five times: one pre-drug and four post-drug measurements, each divided in a condition with and one without 'white noise'. Based on Eysenck's theory it was predicted that the CNV would increase after administering chlordiazepoxide and would decrease after administering caffeine. Furthermore it was expected that 'white noise' would attenuate the CNV of introverts and would enhance the CNV of extraverts. The first hypothesis was significantly verified comparing the chlordiazepoxide group with the caffeine group. However, making comparisons within groups, only the decrease between the measurement before taking caffeine and the first one after administering was significant. The second hypothesis could be supported for introverts only.

Acoustic Stimulation↗
PubMed1978

The contingent negative variation in antisocial behaviour: a pilot study of Broadmoor patients.

Using a classical click/flash paradigm, the CNV was recorded from the following three groups of subjects at Broadmoor Hospital: (1) 14 'psychopathic' patients selected by use of the 4/9 MMPI profile and confirmed by independent clinical diagnosis; (2) 15 'non psychopathic' patients, all psychotic and mainly schizophrenic; (3) 14 healthy staff control subjects. All three groups were matched for age and sex; the two patients groups were also matched for length of stay. Two series of 32 paired stimuli were used, separated by an interval of 30 minutes. The mean CNV voltage was significantly lower in the 'non-psychopathic' patients. The amplitude of the 'psychopath's' CNV response did not differ significantly from that of the staff controls, but the response variability between the first and second series of trials was much greater in the 'psychopathic' patients than in the other two subject groups. The 'psychopathic' subjects tended to show more rapid initial development of the CNV.

Adult↗
PubMed2001

[Interindividual variability of contingent negative variation].

The use of CNV in clinical practice requires the choice of a standardised protocol, the constitution of reference normative data and the consideration of intra- and interindividual variability. For this purpose, we recorded CNV in 86 control subjects (44 men and 42 women, 18 to 62 years old (mean age = 34 +/- 13 years) during a reaction time paradigm with a warning signal and a 1-second S1-S2 interval. Moreover, the role of inter-stimulation interval was analysed in a group of 12 subjects through the comparison of recordings made with 1- and 3-second intervals. The CNV amplitude, its morphology and topographic distribution as well as its resolution mode and evolution through the recording were studied. The subjects' performances and their interactions with electroencephalographic data were also included in the analyses. Our results underscore the contribution of age and gender and psychological factors to CNV variability. CNV amplitude (both M1 and M2) increased and changed topographic distribution toward more central sites in older. Men had faster reaction times than women and lower post-S1 P300. Moreover, the life events-related stress and the subject's current anxiety level were accompanied by a decreased CNV amplitude.

Adolescent↗
PubMed1984

Contingent negative variation in obsessional-compulsive patients.

Obsessional-compulsive disorder has been conceptualised in terms of overattention to irrelevant details. The aim of the present study was to investigate whether this feature would be reflected in the 'early' CNV component. Sixteen obsessional patients and matched controls were tested in a motor-set CNV paradigm with a 5 sec interval between S1 and S2. Patients exhibited a higher amplitude of the 'late' component and male patients prolonged negativity during the first half of trials. In addition, patients yielded lower levels of heart-period than controls. Results are accounted for better by the assumption of uncertainty and doubt in patients compared with controls.

Adult↗
PubMed1981

[Olfactory stimulation and contingent negative variation (CNV) (author's transl)].

In addition to olfactory evoked responses (Fig. 1a) the vertex-negative voltage shift was registered in 20 normal adults. Fig. 2 shows this potential for an olfactory indicative stimulus followed by a tone burst or flash sequence, which are stopped by the test person's manual reaction. In Fig. 3 two alternating odorous stimuli are presented, one of which is followed by the tone. The selective expectancy wave is followed by the tone. The selective expectancy wave is only built up by the marked olfactory stimulus. For the first time CNV can be used as a clinical investigation tool to confirm central perception of odorous stimuli and furthermore to objectivate impaired central odour discrimination (parosmia).

Adult↗
PubMed1975

Effect of motor-response-deprivation on contingent negative variation (CNV). I: Normal adult data.

CNV's were obtained in S1-S2-MR paradigm from 22 normal subjects between the ages of 19 and 67 years (the mean age, 33.5+/-12.5). And then the effect of the presence or absence of a motor response on the CNV was studied. Results were as follows; (1) In the control session (S1-S2-MR), the mean CNV amplitude was 14+/-5 muV, and the mean response time was 291+/-76 msec. There was no significant difference with age, but the mean CNV amplitude for female was significantly higher than that for male. (2) Under the nonresponse condition (S1-S2) where the subject was instructed to attend to S1-S2 without a motor response, CNV amplitude significantly reduced for all subjects (7+/-5 muV). The mean voltage of the attentive-to-stimuli group was significantly higher than that of the inattentive group, and sex difference was not significant for the attentive group. However, CNV of the inattentive male disappeared completely, while the CNV of the inattentive female was significantly higher (8+/-5 muV). (3) Under the response condition (S1-S2-MR), CNV recovered almost to the magnitude level of the control condition (14+/-3 muV), in spite of the fact that the mean response time was significantly shortened between the control and response sessions. (4) We speculate that CNV changes may be dependent upon the dynamic balance of the excitatory-inhibitory activity.

Adult↗
PubMed1992

Changes in bit-mapped contingent negative variation (CNV) activity due to initial normal involutional processes of the human brain.

Bit-color mapped multicomponent CNV complexes and RTs to S2 evoked with a simple warned CNV/RT paradigm were recorded and measured in 20 selected right-handed very healthy volunteers (10 young adults and 10 presenile subjects, mean age 28.3 and 59.6, respectively). EEG and CNV components (post S1, N1, P2, P3; early CNV; N1200; late CNV; CNV resolution) were recorded from Fz, C3, Cz, C4, P3, Pz, and P4 referenced to linked mastoid electrodes. EOG, RT and stimuli were also recorded. The presenile group differed significantly from the younger group in the auditory post-S1 N1 and early (O-wave) and late (P-wave) CNV complex components. A progressive amplitude reduction limited to frontal leads between O-wave and P-wave, the lowest point being reached in the P-wave, was characteristic in the presenile group. Moreover, presenile subjects showed relatively flat CNV waveshapes of low amplitude and, on the whole, performed a little less well than young ones. This finding suggests that the statistically significant changes in auditory post-S1 N1 and CNV activity recorded in our presenile subjects, without any appreciable deficits in behavioral or mental performance, could be alerting signs of early brain involutional processes related to minimal and subclinical decline in orienting, attentiveness and response preparation capabilities. If such is the case, and it could be confirmed in a larger sample of very healthy subjects, these age-related changes in the presenium might prove to be of considerable practical importance for clinical research.

Adult↗
PubMed1976

Contingent negative variation and the distraction--arousal hypothesis.

Thirty-two normal volunteers were tested in three conditions: (1) a constant-foreperiod reaction-time situation consisting of a flash--tone--key-press sequence (control condition); (2) the addition of a short-term memory task consisting of four letters presented within the flash--tone interval with the requirement that they be repeated after key-press to tone (letters--recall); (3) the presentation of letters without short-term memory (letters--no recall). The task involving short-term memory of letters produced a significant reduction in amplitude of CNV for central (Cz) and parietal (Pz) recording sites. The association of CNV decrease and lengthened reaction time to tone was interpreted as a CNV distraction effect. The accompaniment of this distraction effect by elevated heart rate levels and increased frequency of eyeblinks was considered a distraction--arousal association and an important source of disruption in CNV development. These results were interpreted as support for the distraction--arousal hypothesis and appear to provide a sensitive complex of four measures for the evaluation of psychological processes, including the assessment of psychotropic drug effects. Eyeblink frequency in particular appears to be a sensitive indicator of distraction--arousal processes and a potentially useful measure of disturbed psychological functioning. The finding in control conditions of lower CNV amplitude in frontal than in central and posterior recording sites was viewed as a distraction effect due to efforts at eye movement control. The possibility was raised that frontal areas of the brain mediate sustained (tonic) distraction effects whereas centro-parietal regions mediate phasic distraction effects, at least when produced by stimuli of a lexical nature.

Adolescent↗
PubMed1979

[Contingent negative variation in patients with severe closed head injury--its diagnostic value as a quantitative evaluating method for certain aspect of posttraumatic syndrome (author's transl)].

CNVs were studied in 48 subjects with closed head injury followed by posttraumatic amnesia over than 7 days. Electrical motor-threshold stimulation of the median nerve or subjectively painful stimulation of the fingertip was used for imperative stimulus. An amplitude of CNV and its enhancement by painful imperative stimulus were measured and compared with those obtained from 34 normal subjects. In subacute stage within 3 months after the head injury, correlation between CNV abnormalities and an existence of some noticeable psychiatric disorders was found. In many of the subjects with CNV abnormalities, diffuse slow wave activities were observed in the background EEG, so that it was supposed that CNV abnormalities in subacute stage might reflect diffuse cerebral dysfunction and decreased vigilance. Any statistically significant correlation of CNV abnormalities to an existence of psychiatric disabilities, low score in WAIS and background EEG patterns could not be found in chronic stage 12 months after head injury. However, suppressed CNV was observed in all of 4 subjects who presented generalized epileptic patterns in the background EEG. Many of the subjects with suppressed CNV also showed a small effect of painful imperative stimulus on its amplitude. Statistically significant correlation between CNV abnormalities and work capacity was found. From these findings, together with previous observations (Tsubokawa et al. 19,36,40,44)), it is concluded that the measurement of the CNV is inimitable examination to evaluate certain psychiatric disability which is apt to be overlooked but, in fact, concerned intimately to the work capacity.

Adolescent↗
PubMed1976

Effects of warning-signal modality on the contingent negative variation (CNV).

CNVs were recorded during the S1-S2 interval of a prolonged simple reaction task. In the task, a warning stimulus S1 is followed by an imperative stimulus S2, to which the subject makes a motor response. The differential effects of a visual and an auditory S1 were investigated under two interstimulus interval (ISI) durations (1 and 3 sec). Under the 3 sec ISI condition, the form of the slow negative wave demonstrated clearly a biphasic character: an orientation wave (O wave) following S1 with a peak latency at about 650 msec and an expectancy wave (E wave), which reaches its largest amplitude towards the end of the ISI. Under the 1 sec ISI condition the two components of the CNV are confounded. The O wave had a fronto-central distribution, while the E wave was located precentrally. The O wave was enhanced after an auditory S1, as compared to a visual S1.

Acoustic Stimulation↗
PubMed1996

Contingent negative variation (CNV) and determinants of the post-imperative negative variation (PINV) in schizophrenic patients and healthy controls.

A slowly rising cortical potential shift with negative polarity following the imperative stimulus of a forewarned reaction time task, the 'post-imperative negative variation' (PINV), is regularly observed in schizophrenic patients but not in controls. The topography of the PINV suggests that it may originate in frontal cortical regions. We used a task designed to test two putative prefrontal cortical functions: working memory and processing of ambiguity. Nineteen patients with a chronic schizophrenic disorder and 19 control subjects matched for age, sex, and education participated in two experimental sessions. The EEG was recorded from frontal, central, temporal, and parietal leads over both hemispheres using a DC amplifier. PINV amplitudes were generally larger in patients than in controls. If the result of comparing physical features of the two successively presented stimuli (warning and imperative stimulus) was ambiguous rather than clear, an augmentation of the PINV amplitudes was seen in both groups. If this comparison required high rather than low involvement of working memory functions, PINV amplitudes were augmented in schizophrenic patients only. Scalp distribution of the PINV indicated a left-hemisphere fronto-central PINV maximum in patients, and a right-hemisphere predominance in controls, which was larger following ambiguous stimulus comparisons. These results suggest that ambiguity during the comparison of physical features of successively presented stimuli may be a general factor of the PINV in schizophrenic patients and healthy controls. Augmented involvement of working memory functions, presumably subserved by the prefrontal cortex, specifically affected the fronto-centrally predominant PINV in schizophrenic patients. This result is compatible with the hypothesis of prefrontal cortical dysfunctions in schizophrenia.

Adult↗
PubMed1987

Contingent negative variation (CNV) influenced by preceding slow potential shifts (pSPSs).

The study was undertaken to elaborate the influence of slow potential shifts preceding S1 on the CNV. Eighteen subjects participated in a forewarned reaction time task. The EEG was recorded from F3, F4, Cz, P3 and P4 referred to linked mastoids. Selected averages of EOG-corrected trials with negative, positive and no shifts greater than 8 microV - within 2 sec before S1 at the respective location - were compared. Results showed greater CNV after positive shifts compared to negative shifts (P less than 0.05) and no significant interaction with location. Slow potential shifts before S1 did not affect reaction time. Evidence of a baseline effect is discussed as a ceiling effect as well as an expression of an active regulatory mechanism responsible for a desired activation at S2. As slow potentials may also interact with task conditions, it is suggested first to control the baseline in order to obtain reliable CNV measures, and secondly to use baseline effects as a tool to get insight into brain regulatory mechanisms.

Adolescent↗