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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↗
PubMed2000

The effects on auditory neurocognitive evoked responses and contingent negative variation activity of frontal cortex lesions or ablations in man: three new case studies.

Our previous research in patients with extensive surgical ablations of the prefrontal cortex contradict the hypothesis of some authors that the generators of several auditory event-related potentials (ERPs) (N100; P200; N200; P300; SW), recordable in humans with depth/scalp electrodes and MEG over the prefrontal dorsolateral cortical areas, are essentially located in medial prefrontal and anterior cingulate-limbic cortices. Using a standard CNV paradigm, 21 EEG electrodes and topographic mapping analysis, the post-warning (S1) auditory N100a b c, P200, P300 (binaural clicks) and CNV activity were recorded in three additional patients after extensive dorsolateral and/or medial prefrontal cortex ablations, verified through CT/MRI examinations. No true post-S1/CNV components were recordable over the ablated frontal areas, only sporadic volume-conducted ERPs probably generated in the temporo-parietal lobes or posterior cingulate gyrus. For one of these patients, after excision of a vast right frontal epileptogenic cortical region (including extensive dorsolateral areas, but sparing the fronto-medial cortex and anterior/middle cingulate gyrus), no post-S1/CNV components were recordable over the ablated regions. These latest observations again indicate that independent neuronal generators of several post-S1 auditory and CNV components are located in the dorsolateral supramodal premotor/prefrontal cortical areas which are directly, ipsilaterally connected to the uni/multimodal temporo-parieto-occipital sensory and associative regions through the long, two-way, fairly superficial, superior arcuate-longitudinal and deeper superior and inferior occipito-frontal bundles. Clear and almost constant differences in the latency of some post-S1 N100 subcomponents (especially the time-lapses between onset and the highest amplitude of the N100 a and c) over various posterior, central and anterior cortical areas sequentially involved, roughly measured in 10 normal subjects along the scalp and with MRI cerebral imaging, may probably be accounted for by the transcortical homohemispheric conduction time, which varies in our scalp recordings from 1 cm/0.74-1.28 ms, mean approximately 1 cm/1.02 ms ( approximately 9.8 ms).

Adult↗
PubMed1977

The contingent negative variation (CNV) and speech production: slow potentials and the area of Broca.

The lateral distribution of the CNV was investigated during conditions that required normal male and female subjects to vocalize simple English words in a CNV paradigm. In addition to a non-verbal or comparison condition (Tone-Clicks/Button Press), two word conditions presented stimulus words in either S1 or S2 positions (Word-Tone/Speak; Tone-Word/Speak) and a third condition required a one-word association to the stimulus words (Word-Tone/Speak Association). Monopolar scalp activity was collected from sites that included a location approximating Broca's speech area on the left hemisphere, a homologous comparison site on the right hemisphere, frontal sites (F3, F4) and the vertex (Cz). Although several subjects showed some asymmetrical activity in some of the word conditions, amplitude measures based on CNV averages indicated no consistent lateralization effects over the left hemisphere prior to word vocalizaiton. Negative pretrial shifting was suspected in those conditions in which words appeared as S1 signals.

Acoustic Stimulation↗
PubMed1982

An early resolution of contingent negative variation (CNV) in the discrimination.

This study investigates slow potential shifts that occur during a time discrimination task in man. Three experimental series were presented. In series A, each trial included a 5 sec standard interval (SI) followed by a 3 sec SI-TI delay and then by a 4.5, 5.0 or 5.5 sec test interval (TI). The subjects had to estimate whether SI and TI were equal or different and responded by pressing a left or a right button after TI. In series B, the response was postponed after a 3 sec pre-response interval (PRI) succeeding to TI. Series C established an easier discrimination: only 5 or 8 sec TIs were randomly presented in each trial and the subject had to Judge whether he had ben given the "short' or "long' interval. The intervals SI and TI, in which the subject had to collect temporal information, yielded a systematic pattern of slow potential shifts: CNV was followed by an early and prolonged resolution of negativity in the second half of the interval. By contrast, SI-TI delay and PRI only yielded a classical CNV. The "CNV-early resolution' complex appears as a typical feature of temporal tasks. Its possible relation with cognitive processes leading to temporal judgements is discussed, whereas the presence of the only CNV is interpreted as aN indice of expectancy.

Adolescent↗
PubMed1981

Asymmetries of the contingent negative variation (CNV) and its after positive wave (APW) related to differential hemispheric involvement in verbal and non-verbal tasks.

The CNV and the subsequent positive wave (including both the P300 wave and the slow positivity following it) were recorded at left and right frontal and central electrodes during the performance of tasks in which nine right-handed subjects (male and female) had to determine whether S1 and S2 were the same or different. In one task, works had to be matched for meaning while in a second, faces had to be matched for identity. Words elicited CNVs which were more negative over left than right frontal regions. This effect was reversed when the stimuli were faces. Since the CNV is presumed to reflect processes of anticipation rather than stimulus processing, the asymmetry cannot be explained in terms of the lateralisation of neural mechanisms specialised for the analysis of verbal or visuospatial stimuli. Instead the observation is regarded as evidence for mechanisms of lateral activation of a more general nature than would be necessary for the facultative selection of cognitive mode. The amplitude of the CNV relative to baseline was affected by the amplitude of P300 response to S1. This was larger to faces than words in both hemispheres. A small asymmetry in the positive wave following S2 was observed, the amplitude being greater over the right hemisphere for words and over the left for faces. This is interpreted in terms of the subjective probability of the two types of stimulus for a hemisphere ill-equipped to receive them.

Adult↗
PubMed1990

[The anticipatory potential (contingent negative variation) as an indicator of neuronal information processing in relation to changes in slow potentials in the EEG].

The aim of this study was to investigate the interaction between spontaneous Slow Potential Shifts (SPSs) and the probability effect on CNV amplitudes. Fifteen right-handed volunteers participated in this experiment. The presentation of the stimuli was triggered by spontaneous SPSs (duration: 2 seconds, mean-amplitude: 10 microV) in the EEG signal at Cz. Thus, two different S1s (S1a: 1500 Hz, S1b: 2000 Hz) were presented in a random order with a fixed probability of occurrence of 0.8 for S1a and 0.2 for S1b. Each S1 was followed by a light stimulus (S2) with a constant ISI of 4 seconds. According to the cue, the subjects had to push the left (S1a) or the right (S1b) response button as fast as possible with their right index finger. The order of the 4 experimental conditions (stimulus presentation triggered by negative or positive shifts and recording of negative or positive shifts without any stimuli) in which each subject participated was balanced across subjects. Several significant effects could be found by means of a two-way ANOVA for repeated measures (condition x recording site): Negative shifts were accompanied by smaller CNVs as well as PINVs (resolution deficits) at all recording sites; the probability effect was found to be significant in the positive shift condition at F3, F4, and Cz, but not in the negative shift condition except at Cz for the E-wave. CNVs triggered by negative shifts only showed a significant correlation (-.55) with reaction time. These results together favor a two-component model suggesting that SPSs, spontaneous and evoked, are largely generated by glia depolarization, which is evoked by but outlasts neuronal activity.

Adult↗
PubMed1978

The property of contingent negative variation (CNV) in psychiatric patients: schizophrenia and neurosis.

The CNV parameters (amplitude and morphology) and the relationship between CNV parameters and performances (motor response time) were studied on schizophrenics (15 subjects), neurotics (15 subjects) and normal controls (30 subjects divided into 2 groups) in order to clarify the property of CNV in psychiatric patients. Also, the relationship between CNV and personality traits was investigated in neurotics. Since it has been known that age, sex and psychoactive drugs influence the CNV genesis in normal subjects, the control group method was used for these factors in this study. The results obtained were as follows: 1) Mean amplitudes of CNV's for schizophrenics and neurotics in each session of control, nonresponse and recovery tended to be lower than those for normal controls. Significant differences were found between schizophrenics and normal controls. 2) Correlations between CNV amplitude and response time in schizophrenics tended to be positive, while normal controls showed significantly high negative correlations. These findings were discussed from the viewpoint of the arousal theory of CNV genesis. 3) For the neurotic patients, the personality variables appeared to influence CNV amplitude. 4) Type B-CNV was most frequently seen in all sessions for normal controls. Schizophrenics and neurotics tended to show the increment of type P-CNV in nonresponse sessions without a motor response. 5) "Field Dependency" type-CNV was not found in psychiatric patients. This result did not correspond with the data reported by other investigators. 6) Type III- and type IV-prolonged CNV's appeared almost especially in schizophrenics although type II-CNV was observed in all groups. The mechanism of genesis of the prolonged CNV's was discussed.

Adult↗
PubMed1978

The effect of motor-response-deprivation on contingent negative variation (CNV): the morphology.

Eighty-four healthy subjects (47 males and 37 females) ranging in age between 9 and 76 years were employed in a study of the relations of the CNV morphology with the CNV amplitude, the reaction time and the MPI score. The results were as follows: 1. We classified a new type of Plateau (P) in the negative-going limb (NGL) types. 2. There was no sex difference in the NGL types, but the positive-going limb (PGL) types were influenced by age, and the type II tended to increase between the ages of 40--59 years old. 3. As a whole, the type B in the NGL and the type I in the PGL were most prominent regardless of age, session or paradigm. The type FD was very rare and appeared only in the session N. The types III and IV failed to be found in any healthy subjects. 4. Using the matched control study, the relations of the morphology with the CNV amplitude, the reaction time and the MPI score were analyzed. The conventional CNV amplitude in the sessions C and R increased in the sequences of the types B-A-P and the types I-II, and the CNV amplitudes in the session N increased in the sequences of the types A-B-P and II-I. The reaction time in the sessions C and R tended to prolong in the sequences of the types P-B-A and II-I. With the MPI, as the N-score increased with a decrease of the E-score, the NGL types changed from the type P to A through B in the conventional CNV and from the type A to B or P in the session N, while the PGL types changed from the type I to II in the conventional CNV and from the type II to I in the session N. 5. We suggest that there is a twofold arousal process, specific (task-relevant) and general, behind these types and that the dynamic balance of this process may influence psychological manifestations.

Adolescent↗
PubMed1988

Age differences in contingent negative variation activity of healthy young adults and presenile subjects.

20 selected right-handed very healthy subjects (10 young adults and 10 presenile subjects mean age 28.3 and 59.6) were tested for CNV activity with a simple warned reaction time (RT) paradigm. 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 P3, and in the early (O-wave) and late (P-wave) CNV complex components. A progressive amplitude reduction only in frontal leads between O-wave and P-wave with the lowest point being reached in the P-wave was characteristic in the presenile group. Further, presenile subjects showed relatively flat CNV waveshapes of low amplitude and, as a whole, performed a little less well than young persons. This finding suggests that the statistically significant changes in post-S1 EPRs and CNV activity recorded in our presenile subjects, without appreciable deficits in behavioral and mental performance, could be alerting signs of early brain involutional processes related to minimal and subclinical decrement of 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 could be of considerable practical importance for clinical and research applications.

Adult↗