Initial Contingent Negative Variation Research Articles

The Role of Motor Competences in Predicting Working Memory Maintenance and Preparatory Processing

The purpose of the study was the examination of the longitudinal association between motor competences and changes in preparatory processing during a task requiring working memory maintenance. At baseline, 52 Caucasian children aged 10-12years completed the MOBAK-5 test battery and a Sternberg task, whereas the cue-P300 and the initial contingent negative variation (iCNV) were recorded via electroencephalography. After 9months, the Sternberg task was administered again to assess changes in these neurophysiological indices and behavioral performance. Path analyses revealed that motor competences predicted the change in cue-P300 and iCNV from baseline to follow-up. The present findings indicate that the cognitive control strategy during a task demanding working memory maintenance changes as a function of children's baseline motor competences.

Contingent negative variation for the periodicity of migraine attacks without aura.

Migraine is a primary neuropsychological disorder, although its etiology and pathogenesis are unknown. It has been reported that using contingent negative variation, the periodicity of migraine attacks is three days in adults. However, there is still a lack of relevant reports about the periodicity of migraine without aura in adults. Therefore, we investigated the changes of contingent negative variation in adults with migraine without aura from three to seven days after migraine attacks in order to provide the basis for exploring the circulation periodicity of migraine without aura. This prospective, observational study involved a group of 34 individuals with migraine without aura, who were screened during the three to seven days after a migraine attack without aura. A healthy group (31 individuals) was used as controls to assess the amplitudes of contingent negative variation and habituation of early contingent negative variation. Indices of the amplitudes included overall contingent negative variation, initial contingent negative variation, terminal contingent negative variation, and postoperative negative contingent variation. Differences between these indicators were analyzed. No significant difference was found between the patient and control groups for either the amplitudes of these measures of contingent negative variation or habituation of the early contingent negative variation for three to seven days after a migraine attack without aura (all P > 0.05). Thus, the study reported here found that the periodicity of migraine attacks without aura in adults is more than three days.

The time is “right:” Electrophysiology reveals right parietal electrode dominance in time perception

In the present study, healthy undergraduates were asked to identify if a visual stimulus appeared on screen for the same duration as a memorized target (2 s) while event-related potentials (ERP) were recorded. Trials consisted of very short (1.25 s), short (1.6 s), target (2 s), long (2.5 s) or very long (3.125 s) durations, and a yes or no response was required on each trial. We examined behavioral response as signal detection (d′) and response bias via a Generalized Accuracy Coefficient (GAC). We examined the mean amplitude as well as the change in amplitude of the initial Contingent Negative Variation (iCNV) and overall CNV (oCNV) and P350 (a P300-like component that follows stimulus extinction) potentials in paired, lateralized posterior electrodes. Results showed a bias to identifying shorter trials as the target more than longer trials via negative GAC scores. The slope and amplitudes of the iCNV and oCNV were consistently greater in right parietal electrodes. Also in right parietal electrodes, the iCNV correlated to d′ scores while greater P350 amplitudes in the short condition correlated with more negative GAC scores. The results indicate dominance in the right hemisphere in temporal processing for durations exceeding 1 s. The P350 should also be studied further.

The effects of a school-based exercise program on neurophysiological indices of working memory operations in adolescents

ObjectivesTo examine the effects of a structured exercise program implemented during school break-time on working memory maintenance and neurophysiological indices of task preparation processes in adolescents. DesignUsing class-wise random allocation, participants from four classes were divided into an exercise (n=20) and a wait-list control group (n=16). Over a period of eight weeks, the exercise group engaged in 20min of combined aerobic and coordinative exercise on each school day. MethodsPrior to and after the intervention period, participants performed a computer-based Sternberg task for the assessment of working memory performance. Simultaneously, the contingent negative variation (CNV) of event-related potentials was measured. ResultsThe exercise group demonstrated a larger decrease in reaction time from pre- to post-test relative to the control group, F(1, 31)=13.5, p<0.001. No changes were found for accuracy on the Sternberg task across groups. Using cluster-based permutation testing, the analysis of event-related potentials revealed a significant increase of the initial CNV from pre- to post-test in the exercise group, cluster value=−2376.2, p=0.006, which was most pronounced for the fronto-central region, with no such effect observed for the control group. ConclusionsDaily engagement in a short combined aerobic and coordinative exercise program following the school lunch time break elicits benefits for working memory in adolescents. These changes are accompanied by improvements of task preparation processes, which allow the selection of a more appropriate cognitive control strategy.

No deficit in neurocortical information processing in patients with cleft lip and palate.

Cleft lip and palate (CLP) represents the most common malformation of the midfacial region worldwide. It can be suggested that the facial stigmatization, the speech impediment, and the long-standing pressure of treatment cause a range of life stressors. Neurocortical information is influenced by physiological and psychological factors and varies significantly in patients suffering from chronic stress, anxiety, depression, or other psychopathological conditions following maladaptation. The aims of the present study were to investigate the neurocortical information processing of patients with CLP using the contingent negative variation (CNV) paradigm and to evaluate secondary psychopathology, anxiety, and depression. Twenty-five adults with CLP and 25 healthy volunteers, matched in age and gender, were investigated using recordings of the CNV. Initial CNV (iCNV), late CNV (lCNV), and total CNV (tCNV) as well as habituation slope of the iCNV were determined in each subject. Additionally, each participant had to complete the hospital anxiety and depression questionnaire (HADS) and the Symptom Checklist-90-R (SCL-90-R). Individuals with CLP did not differ significantly from healthy subjects according to any of the CNV parameters investigated. No correlations could be revealed between the measured items and the confounding factors age and gender. Additionally, there were no differences between the groups regarding depression and SCL-90-R; however, anxiety showed significant group differences on a subclinical level. These data suggest that subjects with CLP show normal neurocortical information processing. It seems likely that CLP and its treatment have no impact on psychosocial functioning and neurophysiological mechanisms of attention. The specific living conditions of patients with CLP do not result in disease-specific neurophysiological changes.

Anticipatory processes under academic stress: An ERP study

It is well known that preparing for and taking high-stakes exams has a significant influence on the emotional and physiological wellbeing of exam-takers, but few studies have investigated the resulting cognitive changes. The current study examined the effect of examination-induced academic stress on anticipation in information processing. Anticipation was indexed using the contingent negative variation (CNV). Electroencephalograms (EEG) were collected from 42 participants using the classic S1–S2 paradigm. These participants were preparing for the Chinese National Postgraduate Entrance Exam (NPEE). EEGs were also collected from 21 age-matched, non-exam comparison participants. The levels of perceived stress and state anxiety were higher and both the initial CNV (iCNV) and the late CNV (lCNV) were more negative in the exam group than in the non-exam group. These results suggest that participants under academic stress experienced greater anticipation of upcoming events. More important, for the non-exam group, state anxiety was positively related to both the iCNV and lCNV amplitude, and this correlation existed when trait anxiety was controlled; however, there was no such relationship in the exam group. These results suggested that the cortical anticipatory activity in the high-stressed exam group reached the maximum ceiling, leaving little room for transient increases in state anxiety.

Disease duration of episodic migraine correlates with modified amplitudes and habituation of contingent negative variation.

Cortical habituation in episodic migraine patients without medication overuse headache (MOH), recorded by contingent negative variation (CNV), is often reduced compared with healthy controls. There is evidence that with longer duration of migraine disease (DOD) amplitudes and habituation of CNV become progressively abnormal. The aim of the study was to examine habituation characteristics of contingent negative variation in episodic migraine patients suffering from short- and long-lasting migraine compared to matched healthy controls. 32 migraine patients without aura and without MOH diagnosed according to the revised ICHD-II criteria and 16 age- and sex-matched healthy controls were included. According to DOD, the total sample of migraine patients was divided into two groups (group a: DOD <121 months, n = 17 subjects, group b: DOD >120 months, n = 15 subjects). Both migraine groups did not differ in the number of days of migraine and the duration of attacks. Overall CNV and initial CNV differed significantly between migraine patients and controls, whereas the former produced more negative amplitudes. In the migraine group lack of or deficient habituation occurred, whilst controls showed habituation. There were middle range correlations between the DOD and overall CNV, initial CNV, and y-intercept. Patients suffering from long-lasting migraine produced higher CNV amplitudes with a higher y-intercept. The results are interpreted as "maladaptive plasticity" with a risen intercept in long-lasting migraine.

Cortical Habituation Deficit in Tinnitus Sufferers: Contingent Negative Variation as an Indicator of Duration of the Disease

Cortical attention and habituation parameters are altered in patients suffering from tinnitus. The aim of the study was to quantify cortical attention and habituation parameters in tinnitus patients by recording the contingent negative variation (CNV) response and to correlate amplitudes of different CNV parameters with duration of disease. Twenty patients suffering from tinnitus (median: 44years) and twenty age- and sex-matched healthy controls (median: 41years) were tested by a CNV paradigm. We recorded overall CNV, initial CNV, and terminal CNV and calculated habituation slopes. All CNV parameters were Spearman-correlated with individual duration of disease. Highly significant between groups differences emerged in total (tinnitus: -8.4uV vs. controls: -3.8uV), initial (-11.2 vs. -6.0uV), and terminal CNV (-11.9 vs. -6.5uV) demonstrating higher negative amplitudes in tinnitus patients. Habituation differed in total and terminal CNV, indicating missing habituation in tinnitus patients. Overall CNV (ϱ=-.365) and initial CNV (ϱ=-.529) showed a medium Spearman correlation with duration of disease. We conclude that the correlation between duration of tinnitus and the initial CNV amplitudes indicates an altered state of cortical excitability that can also be observed in more negative CNV-amplitudes in tinnitus patients. We assume that this state indicates a chronicity process in tinnitus disease.

The effects of an afterschool physical activity program on working memory in preadolescent children.

The present study examined the effects of a 9-month randomized control physical activity intervention aimed at improving cardiorespiratory fitness on changes in working memory performance in preadolescent children relative to a waitlist control group. Participants performed a modified Sternberg task, which manipulated working memory demands based on encoding set sizes, while task performance and the contingent negative variation (CNV) event-related brain potential were measured. Analyses revealed that the physical activity intervention led to increases in cardiorespiratory fitness and improved Sternberg task performance. Further, the beneficial effects of the physical activity intervention were greater for a task condition requiring greater working memory demands. In addition, the intervention group exhibited larger initial CNV at the frontal electrode site, relative to the waitlist group at post-test; an effect not observed during the pre-test. These results indicate that increases in cardiorespiratory fitness are associated with improvements in the cognitive control of working memory in preadolescent children.

Temporo-Spatial Dynamics of Event-Related EEG Beta Activity during the Initial Contingent Negative Variation

In the electroencephalogram (EEG), early anticipatory processes are accompanied by a slow negative potential, the initial contingent negative variation (iCNV), occurring between 500 and 1500 ms after cue onset over prefrontal cortical regions in tasks with cue-target intervals of about 3 s or longer. However, the temporal sequence of the distributed cortical activity contributing to iCNV generation remains unclear. During iCNV generation, selectively enhanced low-beta activity has been reported. Here we studied the temporal order of activation foci in cortical regions assumed to underlie iCNV generation using source reconstruction of low-beta (13–18 Hz) activity. During the iCNV, elicited by a cued simple reaction-time task, low-beta power peaked first (750 ms after cue onset) in anterior frontal and limbic regions and last (140 ms later) in posterior areas. This activity occurred 3300 ms before target onset and provides evidence for the temporally ordered involvement of both cognitive-control and motor-preparation processes already at early stages during the preparation for speeded action.

Component-Specific Self-Regulation of Slow Cortical Potentials and its Effect on Behavior: An Exploratory Study

In the present study, the possibility of component-specific self-regulation of the contingent negative variation (CNV) and the functional significance of the iCNV (initial or early CNV component) and tCNV (terminal or late CNV component) were investigated in twenty-four healthy volunteers. The subjects were able to achieve control over a particular CNV component within four sessions. Regulation of the tCNV was more successful than for the iCNV. Specific control over iCNV was associated with strategies mainly related to the pre-stimulus interval or the warning stimulus (S1), while regulation of the tCNV was assigned to activities during the whole interstimulus interval or around the imperative stimulus (S2). It can be concluded that component-specific regulation of the CNV can be used in studies of the psychophysiological meaning of this potential, representing different stages of information processing. The role of cortical pre-activation in the generation of the iCNV and the phasic performance-directed activation of the tCNV can be hypothesized.

Developmental changes of the contingent negative variation in migraine and healthy children

It has been hypothesized that abnormalities of information processing in migraine may be attributed to impairment of cerebral maturation. However, the most evidences for this hypothesis have come from cross-sectional studies during childhood. We performed a longitudinal study and recorded contingent negative variation (CNV), an event-related slow cortical potential, in migraine children (n = 27) and age-matched healthy individuals (n = 23) in 1998 and 8 years later (2006). Amplitudes of all CNV components were reduced and habituation of the initial CNV (iCNV) increased in the observed time. However, the reduction of the iCNV amplitude was more pronounced in migraine patients who were in remission in 2006 and in healthy subjects and less pronounced in migraineurs with persisting headaches. Patients with the worsened migraine demonstrated the most pronounced loss of iCNV habituation in 1998 and significantly increased iCNV amplitudes in 2006. This longitudinal study supports the hypothesis of impaired cerebral maturation in migraine and shows that migraine manifestation is a key factor interfering with the natural maturation process of central information processing.

Mobile phones exposure induces changes of contingent negative variation in humans

Event-related potentials have been largely employed to test effects of GSM emissions on human brain. The aim of the present study was the evaluation of initial contingent negative variation (iCNV) changes, induced by 900 MHz GSM exposure, in a double blind design in healthy volunteers, subjected to a threefold experimental condition, EXPOSED (A), a real GSM phone emitting electromagnetic power, SHAM (B), a real phone where the electromagnetic power was dissipated on an internal load and OFF (C), a phone completely switched-off. Ten healthy right-handed volunteers were evaluated. The CNV was recorded during a 10 min time interval in each of the three experimental conditions A, B, and C, in order to assess the iCNV amplitude and habituation. The iCNV amplitude decreased and habituation increased during both A and B conditions, compared with condition C. This effect was diffuse over the scalp, and there was no significant prevalence of iCNV amplitude reduction on the left side, were the phones were located. Mobile Phones exposures A and B seemed to act on brain electrical activity, reducing the arousal and expectation of warning stimulus. This evidence, limited by the low number of subjects investigated, could be explained in terms of an effect induced by both the GSM signal and the extremely low frequency magnetic field produced by battery and internal circuits.

Arousal and Attention: Self-chosen Stimulation Optimizes Cortical Excitability and Minimizes Compensatory Effort

Cortical excitability is assumed to depend on cortical arousal level in an inverted U-shaped fashion: Largest (optimal) excitability is usually associated with medium levels of arousal. It has been proposed that under conditions of low arousal, compensatory effort is exerted if attentional demands persist. People tend to avoid this resource-consuming top-down compensation by creating or selecting environmental conditions that provide sufficient bottom-up stimulation. These assumptions were tested in an attention-demanding dual-task situation: We combined a simulated driving task to induce three different arousal levels by varying stimulation (high vs. low vs. self-chosen) with a visual two-stimulus paradigm to assess cortical excitability by the initial contingent negative variation (iCNV) component of the event-related potential. Additionally, we analyzed the oscillatory power of the beta2 band of the electroencephalogram at anterior frontal sites, which is assumed to reflect low-arousal compensatory activity. The iCNV amplitude differed in all three arousal conditions as expected: It was highest in the condition of self-chosen stimulation and lowest in the low- and high-arousal conditions. Additionally, in the low-arousal condition, anterior frontal beta2 power was found to be significantly higher than in the other two conditions and correlated positively with subjective strain. This pattern of results suggests that subjects select medium levels of stimulation which optimize cortical excitability under attentional demand conditions. The elevated fronto-central beta2 power in the low-stimulation condition may indicate the involvement of the anterior cingulate cortex in compensating for reduced arousal by top-down stimulation of the noradrenergic arousal system.

Effects of topiramate and levetiracetam vs placebo on habituation of contingent negative variation in migraine patients

Migraine is characterized by reduced habituation of multimodal evoked potentials, which in turn reflects an abnormal pattern of cortical excitability. We assessed the effects of a 2-month treatment with topiramate or levetiracetam vs placebo on contingent negative variation (CNV) habituation and amplitude in a cohort of migraine without aura (MO) patients. Forty-five MO patients were selected from a university-based outpatient clinic and randomly assigned to 100mg topiramate or 1000mg levetiracetam or placebo in a double-blind design. Twenty-four control subjects were also recruited. The initial CNV (iCNV) amplitude and habituation were assessed by Cz/A1-A2 derivation recordings in the basal condition (T0) and after 2 months of treatment (T1). Both topiramate and levetiracetam produced a significant reduction in migraine frequency compared to placebo, they also reversed the abnormal iCNV habituation pattern which characterized the MO patients in the basal condition and which was not present in controls. For migraine patients, the reduced migraine frequency and habituation index following treatment were significantly correlated. A lack of habituation of evoked responses is an interictal endophenotypic marker in migraine, the reversion of which may improve disease outcome. These results suggest a role for neurophysiological methods in the management of migraine.

Longitudinal Assessment of Response Preparation and Evaluation in Migraine Gives Evidence for Deviant Maturation

Evidence for deviant maturation of sensory processing in migraine has come recently from cross-sectional studies during childhood. Age-dependent development of response preparation and evaluation is characterized using a longitudinal design in school-aged migraine patients and controls in order to challenge the hypothesis of migraine as a maturation disorder. Forty-six children with migraine and 57 healthy controls aged 6-18 years were investigated and followed up 4 years later using a simple acoustic contingent negative variation (CNV) paradigm. Maturation in controls was characterized by increasing negativity of late and total CNV and stability of initial CNV (iCNV) and the motor postimperative negative variation (mPINV). Migraine patients showed a lack of development for late and total CNV and decreasing iCNV and mPINV negativity. This first longitudinal study confirms cross-sectional results of deviant CNV maturation in migraine. Altered maturation was not correlated with clinical improvement and may represent a vulnerability marker for migraine.

Contingent negative variation before and after hemodialysis among patients with end-stage renal disease

To investigate changes in contingent negative variation (CNV) induced by uremia and to study the effects of hemodialysis. Fifteen right-handed healthy subjects and 12 patients with end-stage renal disease (ESRD) were studied. CNV was recorded from the Fz, Cz and Pz (using the International 10-20 System) referenced to linked ear lobes, using an S1 (click)-S2 (flashes)-key press paradigm. The amplitude of initial CNV (iCNV) was calculated as the average amplitude at 550-750 ms after S1. The amplitude of late CNV (lCNV) was the mean amplitude of the last 200 ms before S2. Testing was repeated for the patient group at pre- and post-hemodialysis observations. Neuropsychological measurements, a trail making test (TMT) and mini-mental state examination (MMSE), were conducted at each time. The mean amplitudes of iCNV and lCNV at the vertex (Cz) were both significantly lower in the patient group than in the control group (P<0.05). TMT were also significantly different between patient and control groups (P<0.05)), however MMSE showed no significant difference. There were no significant correlations between the values of neuropsychological tests and the parameters of CNV. Both iCNV and lCNV were not significantly different between the pre- and post-dialysis tests. CNV negativity in patients with ESRD reflects diffuse nonlocalizing neurological symptoms of uremia rather than a selective involvement of the frontal lobes. It is likely to reflect dysfunction in the frontal-subcortical circuit. In addition, hemodialysis seemed to have no significant effect on executive brain function in these patients with ESRD.

Language lateralization in phonological, semantic and orthographic tasks: A slow evoked potential study

Most of literature on language has shown how different word-classes activate distinct neural networks within linguistic cortical areas. The present investigation aimed to demonstrate that, by means of slow evoked potentials and using the same set of words in different tasks, it is possible to activate cortical networks that are spatially and temporally distinguished. Twenty healthy subjects had to evaluate, in a word pair matching session, whether two words rhymed (phonological task), were semantically related (semantic task) or were written in the same letter case (orthographic task). Slow wave amplitude was computed in three relevant time windows: the last 0.5 s of first word presentation (W1), the initial contingent negative variation (iCNV) and the terminal CNV (tCNV). During W1 and iCNV intervals, both the orthographic and the phonological tasks were left lateralized. Furthermore, the phonological task was more lateralized than the orthographic because of a greater inhibition of the right hemisphere, whereas the orthographic task was characterized by a greater bilateral posterior activation. During the tCNV, only the phonological task remained left lateralized while orthographic and semantic were bilaterally distributed. Although the use of the same set of words tends to activate widely overlapped networks, in the present research task manipulation was effective in demonstrating task dependent differences in brain lateralization. Thus, the present paradigm and the adopted tasks are especially suited for studying deficit and recovery of language in patients affected by linguistic disorders such as developmental dyslexia and aphasia.

Stereotyped topography of different elevated contingent negative variation components in children with migraine without aura points towards a subcortical dysfunction

Increased negativity during contingent negative variation (CNV) is thought to reflect abnormal neural activation in adult migraineurs’ attention related processing. Findings in childhood and adolescence have yielded less clear results. This study characterizes the age-dependent development of CNV topography in migraine during childhood in order to elucidate the origin and cerebral generators of described CNV elevations. A large sample of children with primary headache (migraine with/without aura, tension type headache) and healthy controls aged 6–18 years was examined in a CNV paradigm using 64-channel high resolution DC-EEG. Patients were tested for diagnose-related topographic group differences of initial CNV (iCNV), late CNV (lCNV) and postimperative negative variation (PINV). All three CNV components of 6–11-year-old migraineurs without aura showed elevated negativity over the supplementary motor area (SMA) and around the vertex. Migraine children lacked age-dependent development of late CNV around Cz as previously reported. However, they showed a normal development of late CNV over pre-/primary motor cortex (MI). There was no marked elevation of iCNV amplitude over frontal areas (orienting reaction) nor specific amplitude elevations over “motor” or “sensory” areas during sustained attention (late CNV). Additional “pre-mature” activation e.g., in the locus coeruleus (leading to diffuse cortical activation summing up to a maximum over the vertex) or the basal ganglia (interacting with SMA) explained the rather stereotyped CNV elevation around the vertex better than a specific implication of the cortical systems responsible for orienting, motor preparation or sensory attention.

Relationship between Precipitating Agents and Neurophysiological Abnormalities in Migraine

The particular mechanisms of migraine anticipation by different precipitating agents are still unknown. The contingent negative variation (CNV) was recorded in the premenstrual and ovulation phases of the cycle in both rest and stress conditions in 17 migraine and 15 healthy women. In migraineurs a significant increase of amplitude of the initial CNV component in the premenstrual phase compared with ovulation was observed. During both the ovulation and premenstrual phases both migraineurs and controls demonstrated a significant increase of the CNV amplitude on stress. The increase of the amplitude on stress in the premenstrual phase was more pronounced in migraineurs. This study shows that stress and menstrual cycle are associated with changes of the initial CNV amplitude, probably indicating a higher probability of migraine attacks.