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Results for “Contingent Negative Variation”

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PubMed2001

Four-week test-retest stability of individual differences in the saccadic CNV, two saccadic task parameters, and selected neuropsychological tests.

The aim of the present study was the comparative assessment of the 4-week test-retest stabilities of the saccadic CNV (sCNV) and saccadic reaction times (SRT) during the execution of pro- and antisaccades, as well as the stability of RT during execution of two neuropsychological tests of alertness and S-R incompatibility. Prosaccades were elicited under the 200-ms gap and overlap conditions, antisaccades under the overlap condition (64 trials each). The EEG was recorded from 25 channels with a DC amplifier (MES, Munich). Data of 20 healthy participants were statistically analyzed. We found high test-retest correlations for all SRT (.76 < or = r(tt) < or = .88) and neuropsychological (.62 < or = r(tt) < or = .88) measures. For the sCNV, coefficients ranging between .58 (pro/gap) and .77 (anti/overlap) were obtained. Whereas SRT were significantly faster during the second than during the first session, group means for the saccadic CNV were stable across the sessions. Our results suggest high 4-week stability of individual differences in SRT, and moderate to good stabilities of saccadic CNV amplitudes. Our results recommend these "traitlike" measures to be used in individual differences research.

Adolescent↗
PubMed2001

Is there pre-attentive memory-based comparison of pitch?

The brain's responsiveness to changes in sound frequency has been demonstrated by an overwhelming number of studies. Change detection occurs unintentionally and automatically. It is generally assumed that this brain response, the so-called mismatch negativity (MMN) of the event-related brain potential or evoked magnetic field, is based on the outcome of a memory-comparison mechanism rather than being due to a differential state of refractoriness of tonotopically organized cortical neurons. To the authors' knowledge, however, there is no entirely compelling evidence for this belief. An experimental protocol controlling for refractoriness effects was developed and a true memory-comparison-based brain response to pitch change was demonstrated.

Adult↗
PubMed1975

Electrophysiologic analysis of regional cortical maturation.

Some issues in the study of human neurobehavioral development are briefly set forth. Attention is called to the limitations of strictly structural and behavioral approaches. The value of correlative morphophysiological and psychophysiological investigations is emphasized. By averaging brain activity with respect to stimuli and motor responses, event-related cortical potentials (ERP) can be reliably detected in the scalp EEG. Longitudinal topographic studies of ERP permit the definition of a sequence of regional cortical maturation during infancy and childhood. We have found that evoked potentials in the three major sensory modalities arise from both primary and secondary projection areas by 30 weeks of conceptional age. Frontocentral responses appear shortly thereafter. Thus, cortical mechanisms show a precocious development of electrogenesis which indicates the possibility for an early environmental impact on brain maturation. In contrast to the evoked potentials, association cortex potentials (ACP) do not seem to appear until early childhood. The behavioral significance of these neuroelectric phenomena is being sought in studies employing techniques which permit the concurrent recording of brain activity and behavioral responses in the waking infant and child. Some of the problems confronting the application of these methods to studies of infants are outlined.

Action Potentials↗
PubMed2002

Reduced sensory anticipation in migraine.

We examined differences between migraine patients and matched healthy controls in anticipatory processes preceding a warning stimulus and preceding a response stimulus during a forewarned choice reaction time task. We manipulated stimulus preceding negativity (SPN) by inserting full response information either at the instant of the warning stimulus (cue) or at the instant of the response stimulus. In contrast to control subjects, migraineurs with aura show low anticipation towards an informative cue and high anticipation towards a noninformative cue. Migraineurs without aura showed a cortical hypoactivation during motor preparation prior to the response stimulus. We propose a functional deficiency within frontal structures or the anterior cingulate cortex in migraine. This might explain the reduced anticipation, as well as the slow responses during selective attention that we previously reported in these patients.

Adult↗
PubMed1975

[Levels of slow bioelectric organization of the human brain].

A certain relation between spontaneous pattern and responses to tests of the slow electric processes (SEP) and the order of value of the measured potential was revealed within a single subcortical area of the human brain. A close relation between the constant component (within the range of 110 to 1 mV) and the markedness and character of clinical signs, was observed. A reproducible SEP response to psychological or motor tests was revealed within the ranges of the SEP variable component (from 1000 to 100 mcV and from 5-10 to 50-100 mcV) regarded, respectively, as the ranges of moderate and weak bioelectric signal. The subcortical equivalent and changes of the reproducible pattern in response to meaningless trigrams and words were only observed within the weak signal range. Existence of certain individual ranges of the SEP constant component was revealed in separate neuronal-glial populations. The data obtained show physiological and informative variability of SEP within a single neuronal-glial population in different ranges of the recorded potential's value, which may provide premises for elucidating neurophysiological mechanisms, of different levels for regulation of the links constituting cerebral systems for maintenance of various activities.

Brain↗
PubMed2002

Time course of error detection and correction in humans: neurophysiological evidence.

Using event-related brain potentials, the time course of error detection and correction was studied in healthy human subjects. A feedforward model of error correction was used to predict the timing properties of the error and corrective movements. Analysis of the multichannel recordings focused on (1) the error-related negativity (ERN) seen immediately after errors in response- and stimulus-locked averages and (2) on the lateralized readiness potential (LRP) reflecting motor preparation. Comparison of the onset and time course of the ERN and LRP components showed that the signs of corrective activity preceded the ERN. Thus, error correction was implemented before or at least in parallel with the appearance of the ERN component. Also, the amplitude of the ERN component was increased for errors, followed by fast corrective movements. The results are compatible with recent views considering the ERN component as the output of an evaluative system engaged in monitoring motor conflict.

Adult↗
PubMed2002

[Cortical control of saccadic eye movements: a clinical electrophysiological study of antisaccades].

An antisaccadic paradigm in which saccades are directed towards the mirror location opposite to that of target appearance has been thought to reflect frontal lobe function and a saccade-inhibitory mechanism. In order to clarify now the cortical mechanism differs between antisaccades (AS) and reflexive visually guided saccades (VS), we measured scalp EEG potentials preceding AS and VS in 9 young normal subjects, as well as the magnetic brain activities during AS and VS in 1 of them. Prior to the right and left saccades in both paradigms, our measurements revealed the appearance of a slowly developing negative potential, the presaccadic negativity (PSN), and then a steeper negative potential, the presaccadic steep negativity (PSSN). The onset of PSSN was significantly earlier and the maximum amplitude of PSSN was significantly greater in AS than in VS. The peak amplitude of PSSN at each middle electrode (Fz, Cz, Pz) was generally greater in AS than in VS in both directions of saccades. In one normal subject, the difference between AS and VS in the magnetic field distribution just prior to saccades in both directions was demonstrated as current dipoles on the bilateral frontal areas. Our results suggest that the activation of the bilateral frontal lobes is greater prior to AS than it is prior to VS.

Adult↗
PubMed2002

Intermodal spatial attention differs between vision and audition: an event-related potential analysis.

Subjects were required to attend to a combination of stimulus modality (vision or audition) and location (left or right). Intermodal attention was measured by comparing event-related potentials (ERPs) to visual and auditory stimuli when the modality was relevant or irrelevant, while intramodal (spatial) attention was measured by comparing ERPs to visual and auditory stimuli presented at relevant and irrelevant spatial locations. Intramodal spatial attention was expressed differently in visual and auditory ERPs. When vision was relevant, spatial attention showed a contralateral enhancement of posterior N1 and P2 components and enhancement of parietal P3. When audition was relevant, spatial attention showed a biphasic fronto-central negativity, starting after around 100 ms. The same effects were also present in ERPs to stimuli that were presented in the irrelevant modality. Thus, spatial attention was not completely modality specific. Intermodal attention effects were also expressed differently in vision and audition. Taken together, the obtained ERP patterns of the present study show that stimulus attributes such as modality and location are processed differently in vision and audition.

Adolescent↗
PubMed2002

Bereitschaftspotential in tic disorders: a preliminary observation.

Sensory phenomena in tic disorders such as Tourette's syndrome are known but are substantiated by only a handful of studies. In this preliminary report, we studied premonitory urge, a type of sensory phenomenon in three patients of tic disorders. Bereitschaftspotential, a movement-related cognitive potential indicative of motor preparation, was assessed in these patients. As bereitschaftspotential was observed in all our cases prior to occurrence of tics, it is speculated that tics are not entirely involuntary but are quasi-volitional in nature. Bereitschaftspotential may thus represent a neurophysiological marker of premonitory urge in tic disorders. Implications of exploring the voluntary nature of tics are discussed.

Compulsive Personality Disorder↗
PubMedDate not supplied

[The relationship between a conditioned slow negative potential and focused attention].

A conditioned slow negative vertex potential (CSNP) was studied in the interval between two stimuli: anticipatory and trigger, under different experimental conditions, namely; in response to a trigger stimulus the subject was to press an operating key; or to memorize the number of trigger stimuli; or to respond to the trigger stimulus by pressing the key and memorizing the number of anticipatory stimuli. A sound, geomatrical figures and separate words flashing up on a screen were used as stimuli. All of them were presented both as anticipatory and trigger signals. If a sound was used as an anticipatory stimulus, and a word as trigger one, the recorded CSNP was at its maximum in the case of a simple motor reaction, and at its lowest during retention. When the stimuli interchanged, was drawn to the anticipatory verbal stimulus, the CSNP amplitude diminished and the latency became shorter. The dependence of SCNP parameters on the subject's attention drawn to the anticipatory resp. trigger stimuli is discussed.

Adult↗
PubMed2003

Convergent mechanisms mediate preparatory states and repetition priming in the feeding network of Aplysia.

Improvement of behavioral responses to expected stimuli has been attributed to a change in the preparatory state. In this study, we take advantage of the accessibility of the nervous system of Aplysia and develop an in vitro analog of the preparatory state for feeding behaviors. We provide evidence that the change in the preparatory state may be elicited initially by activity of identified serotonergic metacerebral cells (MCCs). We demonstrate, however, that the preparatory state is maintained through MCC-independent repetition priming that is embedded in the properties of the behavior-generating network. Both MCC-dependent and MCC-independent processes converge on the same site in the behavior-generating network to mediate the change in the preparatory state. Thus, we propose a model of how multiple neuronal structures interact to elicit and maintain changes in the preparatory states in the CNS.

Animals↗
PubMed2003

[Contingent negative deviation in children with headaches].

Contingent negative deviation (CND) was studied in 26 children with migraine and in 20--with headache, tension-type, aged 7-14 years. A control group included 16 healthy subjects. The study was conducted during pain-free intervals, with a 3 s interval between the warning stimulus--S1 and the imperative one--S2. Children with migraine had a higher negative wave amplitude than those with headache, tension type, and controls. Patients suffering from headache had a characteristic postimperative negative wave in the postimpulse period. CND may be considered as an additional index of migraine diagnosis in childhood.

Adolescent↗
PubMedDate not supplied

[The dependence of late evoked cortical potentials on a complex of cognitive factors].

The formation of late evoked cortical responses, N150 and P300, correlates with some factors determining cognitive activity (selective attention, different types of memory, decision making process). Influence of different significance stimuli in a particular situation results in creation of an integral "psychonervous image" reflecting a context of these stimuli, whole complex of cognitive tasks to be solved. It influences significantly on the magnitude of cortical evoked reactions to different stimuli that allows to make a correspondence with the "psychological set" phenomenon and its role in the evaluation of the perceived stimuli.

Cerebral Cortex↗