Is the contingent negative variation contingent on a motor response?
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The contingent negative variation (CNV) is a brain potential generated during delay periods that has been proposed to measure prefrontal cortex (PFCx) activity. The CNV was recorded in neurological patients with PFCx damage centered in Brodmann areas 9, 44, 45, and 46 in a classical auditory S1-S2 paradigm employing a 3 sec interstimulus interval. Subjects pressed a button upon detection of an acoustically cued imperative tone (S2, 1000 Hz, GO). Responses were withheld if the warning tone (S1, 1500 Hz in GO trials) was lower in frequency (500 Hz, NOGO). The early phase of the CNV (500-700 msec after S1) was not reduced in patients with PFCx damage. PFCx lesions reduced the later phase of the CNV beginning about 1000 msec prior to S2. Reductions were maximal over PFCx sites but extended to posterior scalp electrodes over the lesioned hemisphere. The results are consistent with a late CNV generator in dorsolateral PFCx that also modulates generation of the potential in posterior regions of the ipsilateral hemisphere. The CNV findings coupled with behavioral evidence of impaired preparatory processes in these patients support the role of PFCx in sustaining distributed neural activity during delay periods.
The contingent negative variation (CNV) in a warned choice reaction time task was studied in 24 healthy subjects by use of magnetoencephalography (MEG). Special interest was focused on the late component of the CNV, CNVL. Source localization of the magnetically recorded CNVL, mCNVL was performed on 13 subjects, selected on the basis of the strength and stationarity of the electrically recorded CNV, eCNVL. To achieve whole head mapping, up to 500 epochs from different scalp positions were recorded, including a pretrial learning period of 40 epochs. The neuromagnetic signals studied in this experimental protocol are thus related to neurological processes that are present after an initial learning period has occurred. In 11 subjects, a goodness of fit between 88% and 95% was achieved using a two-dipole model with one equivalent source localized close to the precentral cortex contralateral to the side of movement, at mean a depth of 30 mm. Estimates of ipsilateral equivalent sources were less consistent across subjects. In 9 subjects the estimated ipsilateral sources were located symmetrically to the contralateral source. The results of this study suggest that the dominant source of the mCNVL is located near the bottom of the sulcus precentralis at the anterior bank of the gyrus precentralis, close to the sulcus frontalis superior. This supports previous findings that the CNVL is closely related to the readiness potential, and that the major cortical activity is symmetrically located in the left and right premotor areas.
The contingent negative variation (CNV) is a slow cortical potential recorded from the scalp. This method allows the pathophysiology of chronic headaches to be elucidated. When assessed during the pain-free interval patients suffering from migraine without aura show significantly more negative amplitudes than healthy controls. This negativity reflects the activity of cerebral noradrenergic systems. Some studies using repeated recordings of the CNV show a periodicity in amplitude change. When migraine patients are assessed a few days before a migraine attack occurs, they show pronounced negativity, which normalized during the attack. Despite these interesting findings that are based on group comparisons, evaluating the CNV on an individual basis does not allow specific conclusions. Thus, assessment of the CNV is an important tool to examine pathophysiological aspects of chronic headaches, but is not suitable as a diagnostic procedure.
Contingent negative variation (CNV) was recorded from electrodes F7, F3, Fz, F4, F8, T7, C3, Cz, C4, T8, P7, P3, Pz, P4 and P8 in 19 young (mean age: 23 years) and 15 elderly (mean age: 66 years) healthy right-handed subjects, using a S2-choice paradigm. Young subjects showed early peak negativity shortly after the warning stimulus over mid-frontal areas, whereas for the remaining electrodes the negativity increased continuously. The amplitude of the early CNV was selectively reduced in elderly subjects over midline but not lateral frontal areas. We conclude that the activation of frontal midline areas as pre-supplementary motor area or anterior cingulate might be impaired in higher age.
Contingent negative variation /CNV/ is a slow negative potential described first in 1964 by Walter et al. It is a correlate of cerebral activity in the frontal lobes connected with expectation of stimulus and frontal cortex preparation for the stimulus to come. CNV develops in the time between the warning signal /S1/ and the commanding signal /S2/. CNV contains two main components connected directly with brain function: the first one, so called early component, is connected with the process of orientation or warning /it is called also orientation wave/, the second one /late component/ is connected with the preparation for movement /expectation wave or preparatory wave/. The clinical application of CNV is for the evaluation of the correlation of potential changes with changes in cognitive functions occurring in various diseases. Numerous studies reported recently have confirmed the applicability of CNV on the diagnosis of dementia, Parkinson's disease, epilepsy, schizophrenia, anxiety states, chronic pains, including migraine.
Amplitudes of contingent negative variation (CNV) as a slow cortical potential in migraine patients were recorded before and after migraine attacks. The level of CNV amplitudes, especially of the early component, showed a trend in rise of negativity 1 day before the attack, whereas amplitudes were normal for 2-3 days following an attack. In most cases the attack occurred when the CNV amplitude showed maximum negativity. We conclude that migraine-susceptible days are indicated by a high CNV amplitude the day before the attack.
This work, dealing with negative contingency variation (NCV) in mental patients, is in the general frame of research aiming at establishing correlations between biological phenomenons and psychic entities. The results can be examined in three different directions. 1. In the electrophysiological perspective they have individualized a series of physiological forms and brought a real nomenclature. 2. In an electro-clinical perspective, they have allowed to oppose normal curves (NCV, type I, responses to sensory stimulations type A, B, C and motor potential type N) and abnormal curves (NCV zero or type III, IV, responses type D and motor potential type P). One must however stress that this distinction is only valid if one studies adult subjects and awaken, and contributes only an index of non specific morbidity. Furthermore, considering two more electrophysiological criteria--the mode of combination of various curves and the stability of NCV--can help establishing a severity scale and modeling the above data. 3. In a physiopathological perspective, they have lead to discussing two hypotheses concerning the functional signification of prolonged NCV; one being a prolonged state of awaiting, the other a mode of particular reaction to imperative stimulation, and to demonstrate that it is not possible to consider only one and same system to explain all clinical categories. Thus, in this new area of slow cerebral potentials, as in clinical electroencephalography, is illustrated the teaching of the functional electroencephalography through the school of Paris where similar electric patterns have different significations when present in opposed psychological organisations.
topographies of contingent negative variation (CNV) were recorded in a paradigm of delayed response with feedback for three kinds of faces: familiar, strange and target. Subjects made responses to the faces according to whether the faces were familiar or not, but also, gave deliberately deceptive responses to target faces to 'cheat the computer'. Subjects were told that the computer could judge whether they were being honest or not. For each trial of the experiment, if subjects cheated the computer successfully and their responses were judged as honest and they were given a reward, otherwise they received a penalty. In this simulated lie detection test, CNV exhibited more negative shifts for target than those for non-target (familiar and strange). These differences could be accounted for by subjects' motivation and uncertainty about passing the test. With the results of further paired t-tests between target and non-target faces at each electrode, CNV was demonstrated as a reliable indicator for lie detection. In addition, vector length was used to capture global CNV information and was found to be a very good indicator, even better than the CNV information at the individual electrode sites.
Contingent negative variation (CNV), an event-related slow cerebral potential, was analyzed in 79 consecutive headache patients. Compared to normal controls (n = 33), CNV did not differ in tension headache (n = 21) or in combined headaches with a predominant tension component (n = 13). The mean amplitude of CNV was significantly (p less than 0.001) increased in migraine (n = 29) as well as in combined headache with predominant migraine (n = 16). All migraineurs were studied between attacks and without prophylactic treatment. CNV may be a useful diagnostic test in headache. Its increased amplitude in migraine might reflect central catecholaminergic hyperactivity.
We evaluated contingent negative variation (CNV) in 15 right-handed normal subjects who performed simple finger extension(NB) or skilled finger movement task with visual guidance (B). When subjects performed serial tasks of NB-B1 (first block of B)-B2 (second block of B), the CNV amplitudes were larger in BI compared with NB at the left frontoparietal leads for early CNV, at widely distributed areas for the middle CNV and at the left frontopatietal and right frontal leads for late CNV. The present results suggest that the frontoparietal area involving the prefrontal and sensorimotor cortices, plays an important role in visuomotor learning.
OBJECTIVE: The contingent negative variation (CNV) is a widespread electroencephalographic (EEG) potential that occurs during the interval between a warning stimulus and a subsequent imperative stimulus if a mental or motor response is required. The present study was designed to explore the impact of the previous trial on the CNV of the forthcoming trial, that is, how a previous movement affects brain activation preparing the next movement. Effects of alteration of finger (from index to middle, and vice versa) and hand (from left to right, and vice versa) were examined independently from each other. METHODS: CNV was recorded in 20 right-handed healthy subjects with electrodes placed at F7, F5, F3, F4, F6, F8, FC5, FC3, FC1, FC2, FC4, FC6, T7, C5, C3, C1, C2, C4, C6, T8, CP5, CP1, CP2, CP6, P7, P3, P4 and P8. In a visual/visual S1-choice paradigm, an earlier informative (S1) stimulus which instructed for side and finger of the following movement was followed 3 s later by an imperative (S2) stimulus providing the command to move. Subjects had to respond to each imperative stimulus with an appropriate button press made by brisk flexion movements with the index or middle finger of each hand. The CNV recorded in the interval between the informative and the imperative stimulus was analysed with respect to finger and hand of the present and the preceding movement. RESULTS/CONCLUSIONS: (1) A change of the side of movement is associated with a widespread increase of negativity contralateral to the currently prepared movement. (2) A change of finger is associated with a focal increase of negativity contralateral to the side of the current movement over temporoparietal and mid-parietal areas. (3) A change of finger results in a widespread increase of negativity over the left hemisphere.
Contingent negative variation (CNV) was examined in 14 epileptic patients (5 with generalized and 9 with partial fits) both before and after 24 hours of sleep deprivation. Background CNV indices differed significantly by higher amplitudes of nearly all CNV components from the ones of healthy individuals. Amplitudes of postimperative negative waves (PINW) and general waves differed most of all. After sleep deprivation there was an PINW increase as well as the tendency to the late CNV component amplitude's increase. Elevation of CNV amplitudes after sleep deprivation was more pronounced in patients in which the deprivation provoked development of epileptic fits in comparison with patients which endured sleep deprivation rather favourably. The changes revealed in CNV components of the patients with epilepsy were considered in terms of disorders in regulatory mechanisms at the level of apical dendrites of cortical neurons' excitation.
The contingent negative variation (CNV) is a long-latency event-related potential elicited by paired or associated stimuli. We recorded contingent negative variation in 50 patients with complex partial and secondarily generalized seizures and in 20 neurologically and psychiatrically normal unmedicated controls. CNV was recorded from Fz, Cz, and Pz. A 2000 Hz tone was followed after 1.5 s by 1000 microseconds light flash, at which a button press was to be executed. Filter band pass was 0.1-20 Hz, analysis time was 10 s and 10 responses were replicated. Patients with complex partial seizures with and without secondary generalization had lower measurements of area under the CNV curve (AUC) than did controls, and CNV amplitude was significantly reduced. Patients with interictal behavioural symptoms had significantly smaller AUC and lower amplitude. No significant difference was found between depressed and non-depressed seizure patients with respect to AUC, but amplitude was significantly lower in depressed patients. Seizure patients with psychosis had significantly lower AUC but did not differ from non-psychotic patients in CNV amplitude. No differences were found between seizure patients with and without personality disorder with respect to CNV AUC or amplitude. Post-imperative negative variation was significantly more common in seizure patients than in controls and among patients with epilepsy, was significantly increased in those with inter-ictal behaviour disturbance generally and psychosis particularly. No specific effect of anticonvulsant monotherapy on AUC or amplitude was identified. These findings suggest that CNV may differ between partial epilepsy patients and controls, and that inter-ictal behaviour disturbance may particularly affect CNV measures. They also agree with previous evidence for a frontal lobe generator for the CNV, and a possible role for central dopaminergic pathways in the production of PINV.
Contingent negative variations (CNV) were recorded at Cz for young, middle-aged and elderly groups of male and female subjects loaded with simple and discriminative sensory-motor tasks. Each task consisted of repeated single trials in which a warning signal (S1) of click tone was followed 4.0 s later by an imperative visual signal (S2) to which a quick motor response was required. The reaction time to S2 was also measured. In the simple task, a white circle of S2 was presented at probability of 75% on CRT screen, whereas in the discriminative task the subject was given either a green or red circle of S2 on CRT and asked to respond only to a green S2 with key-pressing. The negative component of the S1-S2 interval which was referenced as a baseline voltage during the 500 ms pre-S1 epoch was averaged over at least 12 single trials in each task. The reaction times were averaged over the trials in each task and used as a mean reaction time. A whole mean CNV amplitude averaged over the S1-S2 interval and 16 segmented CNV amplitudes of 250 ms epoch during the S1-S2 interval as well as the mean reaction time, number of erroneous responses and heart rates during both rest and task loading were obtained for each task. These parameters were submitted to 4-way ANOVA (age (3 levels) X gender (2) X task (2) X session (2)). The following age-related changes were observed: the whole mean CNV amplitude and the middle and late components of the segmented CNV decreased significantly with age.(ABSTRACT TRUNCATED AT 250 WORDS)
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Contingent negative variations recorded in 20 tinnitus patients with an average hearing level within 40 dB were compared with those from age-matched healthy controls. In addition, negative and positive potentials (N100 and P300), which are presumed to reflect stimulus information processing, were examined. Contingent negative variation amplitude was significantly greater in patients than in controls (P less than .05, ANOVA), but no significant differences were observed in the N100 and P300 latencies and amplitudes for the two groups. We interpret these results as evidence of abnormalities in the central information processing mechanism of tinnitus patients.