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.     

Neurophysiological Determinants of Tic Severity in Children with Chronic Motor Tic Disorder

Tics wax and wane in severity. Although the understanding of the natural course of symptoms in tic disorder (TD) is important for planning and assessing therapeutic interventions, neurophysiological mechanisms and predictors of tic exacerbation and remission have not been sufficiently investigated. In each of seven children suffering from TD, contingent negative variation (CNV) was recorded on 10 occasions over a period of 2 months. CNV parameters of children with TD were compared with CNV data of healthy, age-matched children. During the entire time of observation, tic severity was assessed by parents and the investigator using a scale developed from the Yale Global Tic Severity Scale. Moreover, tic severity was also evaluated using video assessments. Patients with TD were characterized by significantly lower amplitude of the total CNV and more pronounced habituation of the early CNV component as compared to healthy children. Correlation analysis between tic severity and CNV parameters demonstrated that the more severe the tics were, the lower the amplitude of the total CNV. Since CNV amplitude represents processes of resource mobilization and control over neuronal excitability, tic severity may result from less ability to control neurophysiological functions in patients with TD.     

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: 44?years) and twenty age- and sex-matched healthy controls (median: 41?years) 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: -8.4?uV vs. controls: -3.8?uV), initial (-11.2 vs. -6.0?uV), and terminal CNV (-11.9 vs. -6.5?uV) demonstrating higher negative amplitudes in tinnitus patients. Habituation differed in total and terminal CNV, indicating missing habituation in tinnitus patients. Overall CNV (??=?-.365) and initial CNV (??=?-.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.     

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.     

Locus of Psychological Control and Peculiarities of Event-Related EEG Potentials

In a group including 74 adults of both sexes, we examined interrelations between the locus of psychological control (diagnosed using the Rotter questionnaire) and parameters of event-related EEG potentials, ERPs, recorded in the course of performance of two behavioral test acts with a motor component. Task A corresponded to maximally fast pushing on the button after a signal with warning; the time of the sensorimotor reaction was measured. Task B included internal counting of a definite time interval limited by two pushings on the button. Under these conditions, we recorded the contingent negative variation (CNV), the P300 potential, and, in task B, the readiness potential (RP). EEG leads C3 and C4, according to the 10-20 system, were used. Internals (estimates by the questionnaire, 6 stens or higher) were characterized by higher amplitudes of the terminal CNV (CNV-T), integral CNV, and P300 in task A, by greater RP and CNV amplitudes in task B, and also by shorter reaction times and their smaller dispersion. It should be supposed that the corresponding peculiarities of the neurodynamic constitution of an individual are determined, to a considerable extent, by the specificity of organization and functioning of a few neurotransmitter (aminergic in particular) and neurohumoral systems.     

Two phases of the contingent negative variation in humans: connection with motor and mental functions

The question of dependence of the contingent negative variation (CNV) on the regulating mechanisms of motor and mental functions is not sufficiently studied. The tasks of the present work were: to investigate the dependence of the CNV early and late phases on the state of motor and mental functions in patients with Parkinson's disease (PD), and to elucidate the levodopa influence on the CNV parameters. 18 healthy subjects and 56 patients with PD were studied. In PD patients, significant reductions of amplitudes and squares of two CNV phases were observed. A negative correlation of the degree of coordinating muscle relationships disturbance with amplitudes of two CNV phases was found (p < 0.01). A positive interdependence between values of the both CNV phases and the state of mental functions was established, memory in particular (p < 0.05). After levodopa administration in PD patients, the early CNV phase did not significantly change, whereas the late CNV phase significantly increased (p < 0.05). Results of the investigation suggest an important role of the structures ensuring both direct motor control and mental functions in two CNV phases formation. A more obvious levodopa influence on the late CNV phase suggest participation of the basal ganglia efferent system in generation of the late CNV phase rather than in organization of the early CNV phase.     

Correlation between the parameters of contingent negative variation and characteristics of variational pulsometry in Parkinsonian patients

In patients suffering from Parkinson's disease (PD), we analyzed correlations between the parameters of contingent negative variation (CNV) and data of variational pulsometry (according to the measurements of R-R ECG intervals). Studies were carried out on 35 patients (group PD), 49 to 74 years old, with the stage of disease of 1.5 to 3.0 according to the Hoehn-Yahr international classification. In the course of CNV recording (i.e., in the state of a certain functional loading), we observed significant negative correlations between the integral magnitude (area) of this potential and indices of variational pulsometry (RMSSD, SDNN, C. var, and HF) that characterize the intensity of parasympathetic (respiratory) influences on the cardiovascular system. In the control group, such correlations were absent. We found significant correlations between the autonomic balance, CNV magnitude, and stage of PD reflecting the level of generalization of the pathological process. In the subgroup of patients with the PD stage 1.5 to 2.0, significant changes in the mean values of indices of parasympathetic influences during recording of the CNV were not observed, while in another subgroup (the PD stage 2.5 to 3.0), these values increased significantly (P < 0.05 and P < 0.01). If the estimates of the PD stage were low, the CNV area demonstrated greater values (P < 0.01). The disturbance of coordination of muscle-to-muscle interactions in the PD group is, probably, an important factor responsible for parasympathetic dysregulation and suppression of the CNV generation. We found positive correlation between the intensity of parasympathetic influences in the course of CNV recording and the level of postural disorders (r = 0.37, P < 0.05). On the contrary, the CNV magnitude demonstrated a negative correlation with the intensity of these disorders (r = −0.36, P < 0.05), as well as with the level of postural instability (r = −0.55, P < 0.001). We hypothesize that alterations of the autonomic balance and the activity of those cerebral structures, which are responsible for the motor readiness, result, to a significant extent, from weakening of the activity of the noradrenergic system due to degenerative processes developing in cells of the locus coeruleus. The impairment of the latter structure, together with degeneration of neurons of the substantia nigra and a decrease in the level of nigro-striatal dopamine, underlies the pathomorphological pattern of PD. Neirofiziologiya/Neurophysiology, Vol. 40, No. 3, pp. 242–253, May–June, 2008.     

Evaluation of EEG(D2) and CNV correlation dimension in various forms of visual attention in human

In 16 healthy subjects, the EEG and the CNV (contingent negative variation) correlation dimension was studied during preparing to pay attention to one of three attention tasks: the situations "What", "Where" and "What and where". Two easily discernible symbols (squares and circles) were used as stimuli. The findings show that, irrespective of the attention form, the correlation dimension of the EEG, the CNV amplitude, and the evoked potential's N1-P3 component amplitude had maximal values in the temporal leads. The temporal visual system seems to play a domineering part in the tasks of spatial and non-spatial attention to stimuli in humans.     

Psychological Adaptation Potential of the Personality: Peculiarities of Event-Related EEG Potentials

In a group of 68 adults of both sexes, we examined correlations between the level of psychological adaptability of the personality (diagnosed using the Maklakov questionnaire) and parameters of event-related potentials (ERPs) recorded in the course of performance of two behavioral test acts including a motor component. In task A, it was necessary to maximally rapidly press the button after an imperative signal preceded by a warning signal, while a definite time interval (limited by two pressings of the button) should be measured in task B. Parameters of the contingent negative variation, CNV, potential P300 and, in task B, readiness potential, RP, were measured in C3 and C4 leads. High amplitudes of ERPs (RP, P300, and CNV in task A) and smaller variability of the indices of working efficiency corresponded, in the whole, to higher estimates of psychological adaptability in general and of separate aspects of the latter estimated according to the scales of the used questionnaire. Probable mechanisms of the peculiarities of neurodynamic constitution determining the level of the psychological adaptability of the individual, on the one hand, and of the ERP parameters, on the other hand, are discussed.     

Correlations of the Peculiarities of the Motivational Sphere and Characteristics of Event-Related EEG Potentials in Humans

We studied the relations between generalized characteristics of the state of the motivational sphere, the levels of need for achievements (N-Ach) and achievement motivation (AchM) typical of an individual, and the parameters of cerebral event-related potentials (ERPs). The examined group included 70 adults of both sexes. The ERPs were recorded in the course of realization of two behavioral test acts with motor components. In task А, the subject should press a button with the minimum delay with respect to an imperative signal preceded by a warning signal (with the measurement of the time of sensorimotor reaction); in this case, the contingent negative variation (CNV) and Р300 potential were recorded. Under conditions of task B, the subject should measure a definite time interval limiting the latter by two pushings of the button; in this case, the readiness potential (RP) was recorded in addition to CNV and Р300. The ERPs were recorded in the С3 and С4 leads (according to the 10-20 system). The peculiarities of the motivational sphere were diagnosed using Orlov’s and Mechrabian’s questionnaires. We found that a relatively high amplitude of the early CNV component (СNV-O) and low amplitudes of the integral CNV and Р300 in task A and a low amplitude of the RP can serve as task B-related EEG markers of a high NA level. In task A, high levels of the AchM correlated with higher amplitudes of the CNV and Р300, and amplitudes of these potentials were higher in the left hemisphere. The observed interrelations were probably determined by a considerable dependence of the N-Ach and AchM characteristics, on the one hand, and CNV amplitude parameters, on the other hand, on the hereditary factors, in particular neurochemical ones. It is obvious that such peculiarities of the neurodynamic constitution of an individual are, to a considerable extent, determined by the specificity of organization and functioning of a few neurotransmitter (in particular aminergic) and neurohumoral systems.     

Activation of the human cortex during visual attention and selection

Cortical activation in visual discrimination tasks was estimated by measurement of the CNV (contingent negative variation) and N1-P3 components of visual ERPs in frontal, parietal, occipital and temporal leads recorded in 18 young healthy adults. In all investigated tasks, the maximal values of CNV and ERPa were observed in parietal regions. The estimation of cortical readiness state (CNV) is quite a useful procedure in the attention tasks because amplitude and stability of ERPs depend on preceding cortical excitability. The prevalence of parietal activation in visual attention tasks may be considered as the dominance of occipito-parietal way (stream) in human visual attention system.     

Individual personality-related characteristics of event-related EEG potentials recorded in an experimental situation requiring production of time intervals

Event-related EEG potentials (ERP) were recorded from 75 tested adult men and women; recording was performed from C3 and C4 points. The experimental situation required internal counting of time intervals limited by two pushes of a button. The experimental paradigm provided a substantial level of uncertainty, and a high level of attention needed to be maintained. The tested subjects were not informed by the experimenter about the precise value of the preset time interval; they knew only its limits, 17–23 sec. The subject obtained information about the agreement or disagreement between the produced interval and its value preset by the experimenter by visual feedback signals obtained 2 sec after termination of counting; in the case of agreement the subject had to perform a confirming (third) push of the button. Pushes were preceded by readiness potentials (RP); contingent negative variation (CNV) developed before the feedback signals, and the latter were accompanied by P300 potentials. Significant positive correlations were found between the parameters of RP and P300 in both hemispheres. In general, ERP were characterized by very high interindividual variability, which in a few respects correlated with the personality-related characteristics of tested subjects evaluated by psychological testing with the use of corresponding questionnaires. In particular, under the experimental conditions used, negative correlations were observed between the RP amplitude and psychotism indices, CNV amplitude and emotional stability; CNV amplitude and extroversive features, and P300 amplitude and domination properties of a person. Positive correlations were observed between the CNV amplitude and autia factor (according to Eysenck’s PEN and Cattell’s 16 PF questionnaires). We suppose that correlations between the personal psychical features and ERP parameters are grounded in both inherited constitutional specificities of the nervous system and neurochemical/structural modifications in the brain determined by the acquired vital experience.     

Analysis of copy number variants in the cattle genome

Copy number variation (CNV) is likely to be an important component of heritable variation in livestock. To characterise CNVs in cattle, we performed a genome wide survey to determine the number, location and gene content of these genomic features. A tiling oligonucleotide array with ~385,000 probes was used for comparative genomic hybridisation of both taurine and zebu cattle. Using a conservative set of calling criteria, a total of 51 CNV were detected that collectively spanned approximately half of one percent of the bovine genome. The size of the average CNV within each animal ranged from 213 kb up to 335 kb. Half of the CNV were detected in a single animal only, whilst the remainder was independently identified in multiple individuals. Analysis was performed to determine the gene content for each CNV region. This revealed that the majority of CNV (82%) spanned at least one gene, with a number of CNV containing genes which are known to control aspects of phenotypic variation in cattle. Whilst additional studies are required to determine the impact of individual CNV, this study confirmed them as an important class of genomic variation in cattle.     

Reliability and upper normal variability limits of pattern reversal visual evoked potential parameters.

Twenty healthy volunteers aged 21-48 years (10 males, 10 females) were submitted to pattern reversal visual evoked potentials with 15' and 30' checks. The recordings were repeated after 7 days to assess reliability and upper normal variability limits of the following parameters: latencies of N70, P100, N140 and peak-to peak amplitudes of N70-P100, P100-N140. Reliability was tested with intraclass correlation coefficient, which was excellent or good for all parameters. Test-retest variability limits were computed with = 0.01 for absolute latency differences and relative amplitude differences.     

Copy number analysis of complement C4A, C4B and C4A silencing mutation by real-time quantitative polymerase chain reaction

Low protein levels and copy number variation (CNV) of the fourth component of human complement (C4A and C4B) have been associated with various diseases. High-throughput methods for analysing C4 CNV are available, but they commonly do not detect the most common C4A mutation, a silencing CT insertion (CTins) leading to low protein levels. We developed a SYBR? Green labelled real-time quantitative polymerase chain reaction (qPCR) with a novel concentration range approach to address C4 CNV and deficiencies due to CTins. This method was validated in three sample sets and applied to over 1600 patient samples. CTins caused C4A deficiency in more than 70% (76/105) of the carriers. Twenty per cent (76/381) of patients with a C4A deficiency would have been erroneously recorded as having none, if the CTins had not been assessed. C4A deficiency was more common in patients than a healthy reference population, (OR?=?1.60, 95%CI?=?1.02-2.52, p?=?0.039). The number of functional C4 genes can be straightforwardly analyzed by real-time qPCR, also with SYBR? Green labelling. Determination of CTins increases the frequency of C4A deficiency and thus helps to elucidate the genotypic versus phenotypic disease associations.     

Correlations between the level of aggressiveness of personality and characteristics of event-related EEG potentials

In a group of 76 adults of both sexes, we examined interrelations between the level of aggressiveness of the individual (diagnosed using the Buss-Durkee Hostility Inventory) and parameters of event-related EEG potentials (ERPs) recorded under conditions of two behavioral test acts including a motor component. Within the framework of task A, the subject must push a button with the shortest delay after an executory signal preceded by a warning signal; the time of sensorimotor reaction was measured. Under these conditions, we recorded the contingent negative variayion (CNV) and the P300 potential. In the case of task B, it was necessary to measure a definite time interval limited by two pushings of the button. Under these conditions, the readiness potential (RP) was recorded in addition to the CNV and P300. The C3 and C4 leads were used (according to the 10–20 system); the time constant of an amplification tract was 10 sec. Despite natural broad interindividual variability, high amplitudes of the recorded ERPs (RP, CNV, and P300) in general corresponded to lower indices by scales of the Buss-Durkee inventory and smaller values of the indices of aggressiveness and hostility. These interrelations are, probably, based on the fact that both characteristics of aggressiveness of the personality and EEG amplitude parameters are to a considerable extent determined by hereditary factors. It is believed that the respective peculiarities of the neurodynamic constitution of the individual are to a great extent dependent on the specificities of organization and functioning of a few neurotransmitter (in particular, aminergic) and neurohumoral systems. Neirofiziologiya/Neurophysiology, Vol. 39, No. 2, pp. 154–164, March–April, 2007.     

A Coronary-Prone Type of Personality: Peculiarities of Event-Related EEG Potentials

In a group of 70 adults of both sexes, we examined interrelations between the estimates of expression of a coronary-prone type (type A) of the personality (measured using the Jenkins questionnaire) and the parameters of event-related EEG potentials (ERPs). The latter potentials were recorded in the course of performance of two behavioral test tasks including motor components. Within the framework of the “A” task, the subject is had to maximally rapidly push the button after a signal with warning (with measurement of the latency of the sensorimotor reaction); under these conditions, we recorded the contingent negative variation (CNV) and P300 potential. In the case of the “B” task, a definite time interval was to be measured and limited by two pressings of the button. In this task, the readiness potential (RP) was recorded in addition to the CNV and P300. The C3 and C4 EEG leads (according to the 10–20 system) were used. Within the framework of the “A” task, subjects belonging to the coronary-prone type were characterized by the lowest amplitudes of the CNV and its separate components and also by greater amplitudes and relatively long latencies of the P300 wave. Persons of type B were distinguished by the highest CNV amplitudes in both hemispheres, while values of the P300 amplitude in this group were usually medium. In the “B” task, representatives of type A demonstrated the lowest RP and P300 amplitudes, especially clearly pronounced negative CNVs in the left hemisphere, and relatively long P300 latencies; individuals belonging to type B showed the highest RP and CNV amplitudes in the right hemisphere and medium values of the P300 amplitude. The correlations found are probably due, to a considerable extent, to the fact that both characteristics of the behavioral types A and B and amplitude parameters of ERPs depend significantly on genetically determined neurochemical factors, namely specificities of organization and functioning of a few neurotransmitter (in particular, aminergic) and neurohumoral systems.     

Adaptation changes in dynamic postural control and contingent negative variation during repeated transient forward translation in the elderly

Background

Adaptation changes in postural control and contingent negative variation (CNV) for the elderly were investigated during repeated forward floor translation.

Methods

Fifteen healthy elderly persons, living in the suburban area of Kanazawa City, Japan, underwent backward postural disturbance by a forward-floor translation (S2) 2 s after an auditory warning signal (S1). A set with 20 trials was repeated until a negative peak of late CNV was recognized in the 600-ms period before S2, and the last set was defined as the final set. Electroencephalograms, center of foot pressure in the anteroposterior direction (CoPap), and electromyograms of postural muscles were analyzed.

Results

CoPap displacement generated by the floor translation was significantly decreased until the twelfth trial in the first set, and mean CoPap displacement was smaller in the second and final sets than in the first set. The mean displacement was significantly smaller in the final set than the previous set. A late CNV with a negative peak was not recognized in the first and second sets. However, most subjects (13/15) showed a negative peak by the fourth set, when the late CNV started to increase negatively from about 1,000 ms after S1 and peaked at about 300 ms before S2. At about 160 ms before the CNV peak, the CoPap forward shift started. The increase in timing of the gastrocnemius activity related to the CoPap shift was significantly correlated with the CNV peak timing (r = 0.64). After S2, peak amplitudes of the anterior postural muscles were significantly decreased in the final set compared to the first set.

Conclusions

It was demonstrated that even for the elderly, with so many repetitions of postural disturbance, a late CNV with a negative peak was recognized, leading to accurate postural preparation. This suggests the improvement of frontal lobe function (e.g., anticipatory attention and motor preparation) in the elderly.     

Migraine and Meditation: Characteristics of Cortical Activity and Stress Coping in Migraine Patients,Meditators and Healthy Controls—An Exploratory Cross-Sectional Study

The aim of this exploratory cross-sectional study was to investigate the characteristics of cortical activity and stress coping in migraine patients, meditation experienced subjects, and healthy controls. 45 meditation experienced subjects, 46 migraine patients, and 46 healthy controls took part in the study. Cortical activity was measured with the contingent negative variation (CNV), a slow cortical event-related potential. Stress coping was examined with the standardized Stress Coping Questionnaire SVF-78. A one-way analysis of variance was used to investigate possible differences between the groups. CNV-amplitude was significantly higher in migraineurs than in controls. The meditators showed significantly lowest amplitudes. Migraine patients used negative stress-coping strategies significantly more often than meditators and healthy controls. Especially the application of the strategy “rumination” was most frequent in migraine patients and least frequent in meditators. Moreover, frequent rumination was significantly correlated with high CNV-amplitudes. Cortical and stress processing in people with meditation experience was improved compared to migraine patients and healthy controls.     

Ontogenetic characteristics of the development of slow negative and positive potentials during the performance of a visual perceptive task

In age aspect, topography and parameters were studied of late EPs and slow negative components (CNV) to successively presented visual stimuli: the preliminary signal and two compared contour images. Age characteristics of development of the frontal negativity N450 and the late positive complex (LPC) were revealed. in children 7 and 10 years old, the component N450 was present in response both to the preliminary and the first stimulus in the compared pair; LPC was recorded to all three presented visual stimuli. In 17 years old subjects and in adults, selectivity of N450 formation in the EP to the first of the compared stimuli and LPC to the second (imperative) stimulus correlates with involvement of rostral brain areas--central in youths, central and frontal ones in adults--both in the process of waiting (CNV) and evaluation of coming information (LPC).