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PubMed1987

Human event-related potentials and circadian variations in arousal level.

Contingent negative variation (CNV) potentials were recorded from ten male subjects during a single session in divided- and focussed-attention conditions. Beside a strong dependency of CNV and N1 amplitudes and reaction time on task difficulty, the results of the present study show an effect of the subject types, classified by their peak performance times. The slight increase of CNV amplitude form morning to afternoon recording in evening-type subjects contrasted with a substantial decline in the morning-type subjects. Unexpectedly, both task conditions showed remarkably similar time courses of amplitudes. The attempt to model the individual amplitude curves from arousal levels led to inconclusive results. No final conclusions about the relationship of CNV and arousal levels over the course of a day can be drawn.

Adult↗
PubMed1988

Subjective cognitive dysfunction, eye tracking, and slow brain potentials in schizophrenic and schizoaffective patients.

The relationships between subjective cognitive dysfunction (so-called basic symptoms) and some psychophysiological measures were examined repeatedly in schizophrenic and schizoaffective patients during an acute psychotic episode, and comparisons were made with psychotic symptom ratings. Psychophysiological variables were: quality of eye tracking, amplitude measures of the contingent negative variation, and reaction time. Ratings of psychotic and basic symptoms were significantly correlated, but only the basic symptom score showed significant associations with eye tracking, contingent negative variation, and reaction time. Although this pattern was confined to the recovery phase of the psychotic episode, the results suggest that the core psychopathological correlates of these psychophysiological measures consist of basic symptoms rather than florid psychotic symptoms.

Adult↗
PubMed2006

The effect of response type (motor output versus mental counting) on the intracerebral distribution of the slow cortical potentials in an externally cued (CNV) paradigm.

OBJECTIVE: Previous surface CNV studies including a hand motor output have suggested that the late phase of the CNV reflects the preparation of the sensorimotor cortices involved in the motor output given the same similarity in scalp potential distribution with readiness potential. However, the poor spatial resolution of the scalp recorded CNV data prevented a definitive conclusion. This intracerebral study allowed us to test this hypothesis using a CNV paradigm in which a non-motor task is used as a reference. This study concerned the intracerebrally located generators of the Contingent Negative Variation in two different paradigm settings: (i) motor output required, (ii) silent counting required (non-motor control condition). METHODS: Stereoelectroencephalography (SEEG) recordings of the contingent negative variation (CNV) in a somato-somatosensory stimulation paradigm with a motor or counting task were taken from nine patients with drug-resistant epilepsy. The intracerebral recordings were taken from 25 cortical areas in both hemispheres (supplementary motor area-SMA; the cingulate gyrus; the orbitofrontal, premotor and dorsolateral prefrontal cortices; lateral temporal cortex, amygdalohippocampal complex; and the parietooccipital cortex). RESULTS: The slow waves were generated in the SMA, the premotor, dorsolateral, and orbitofrontal cortices, the cingulate gyrus, and parts of the lateral temporal, mesial temporal structures and parietal cortex. We found a significant difference between the two tasks in the CNV potential generation. The task with the motor output produced significantly higher numbers of CNV potential generators when compared to the task with silent counting. CONCLUSIONS: The CNV potential generators varied between motor and non-motor tasks. The intracerebral distribution of the potentials linked with expectation is task dependent. Our main conclusion is that the executive network is more active during the motor task than during counting task.

Adolescent↗
PubMed2001

Current source density analysis of CNV during temporal gap paradigm.

The present report studied the contingent negative variation during Gap and Non-Gap conditions using visual stimulation and manual responses. The reaction times during the Gap condition were facilitated compared with those of the Non-Gap condition. The contingent negative variation component was obtained during the preparatory period from electrodes placed at 58 scalp sites for both Gap and Non-Gap conditions. The comparison between both conditions: Gap and non-gap did not show statistically significant differences during the preparatory period. The topography of the voltage and current source density maps showed three different foci: (i) an early negativity centred in electrodes overlying the supplementary motor area and cingulate motor areas, (ii) an activation over the primary motor cortex contralateral to the finger movement, and (iii) a bilateral activation on posterior sites. All these results suggest that the facilitation induced by the warning stimuli occurs in neural circuits that would be recruited for the subsequent processing of the imperative stimulus. The facilitation of the reaction times during the gap condition with respect to non-gap condition must be justified by neural events occurring during the gap period.

Adolescent↗
PubMed2003

Cortical and subcortical distribution of middle and long latency auditory and visual evoked potentials in a cognitive (CNV) paradigm.

OBJECTIVE: This study concerned sensory processing (post-stimulus late evoked potential components) in different parts of the human brain as related to a motor task (hand movement) in a cognitive paradigm (Contingent Negative Variation). The focus of the study was on the time and space distribution of middle and late post-stimulus evoked potential (EP) components, and on the processing of sensory information in the subcortical-cortical networks. METHODS: Stereoelectroencephalography (SEEG) recordings of the contingent negative variation (CNV) in an audio-visual paradigm with a motor task were taken from 30 patients (27 patients with drug-resistant epilepsy; 3 patients with chronic thalamic pain). The intracerebral recordings were taken from 337 cortical sites (primary sensorimotor area (SM1); supplementary motor area (SMA); the cingulate gyrus; the orbitofrontal, premotor and dorsolateral prefrontal cortices; the temporal cortex, including the amygdalohippocampal complex; the parietooccipital lobes; and the insula) and from subcortical structures (the basal ganglia and the posterior thalamus). The concurrent scalp recordings were obtained from 3 patients in the thalamic group. In 4 patients in the epilepsy group, scalp recordings were taken separately from the SEEG procedure. The middle and long latency evoked potentials following an auditory warning (S1) and a visual imperative (S2) stimuli were analyzed. The occurrences of EPs were studied in two time windows (200-300 ms; and over 300 ms) following S1 and S2. RESULTS: Following S1, a high frequency of EP with latencies over 200 ms was observed in the primary sensorimotor area, the supplementary motor area, the premotor cortex, the orbitofrontal cortex, the cingulate gyrus, some parts of the temporal lobe, the basal ganglia, the insula, and the posterior thalamus. Following S2, a high frequency of EP in both of the time windows over 200 ms was observed in the SM1, the SMA, the premotor and dorsolateral prefrontal cortex, the orbitofrontal cortex, the cingulate gyrus, the basal ganglia, the posterior thalamus, and in some parts of the temporal cortex. The concurrent scalp recordings in the thalamic group of patients twice revealed potentials peaking approximately at 215 ms following S1. Following S2, EP occurred with latencies of 215 and 310 ms, respectively. Following S1, separate scalp recordings in 4 patients in the epilepsy group displayed EP 3 times in the 'over 300 ms' time window. Following S2, EP were presented once in the '200-300 ms' time window and 3 times in the 'over 300 ms' time window. CONCLUSIONS: The SM1, the SMA, multiple sites of the frontal lobe, some parts of the temporal lobe, the cingulate gyrus, the basal ganglia, the insula, and the posterior thalamus all participate in a cortico-subcortical network that is important for the parallel cognitive processing of sensory information in a movement related task.

Adolescent↗
PubMed1997

Responses to cued signals in Parkinson's disease. Distinguishing between disorders of cognition and of activation.

Impairment of movement execution in Parkinson's disease could be due to disorders of cognition and/or of activation. These two factors are hard to separate by measuring response times only. Therefore, in this study response force and event-related EEG potentials were measured continuously during tasks in which subjects had to respond to cued signals. Fifteen patients with Parkinson's disease and 15 healthy subjects were studied during two tasks: (i) the 'clock task', in which the signal's identity was fully precued but its presentation time was uncertain and (ii) the 'validity task' in which the cue did not always predict the response validly. Thus, the clock task required more sustained attention, and the validity task sometimes required fast switching. The patients generally responded slower than control subjects. In the clock task, the response times of both groups changed to the same extent with presentation time, whereas in the validity task the patients were additionally slower than the control group with invalidly cued signals. The patients generally had a weaker response force and a lower rate of force production. In the clock task, both force measures changed with presentation time in the control group only, whereas in the validity task, the two measures increased in both groups to the same extent with invalidly cued signals. The contingent negative variation amplitudes in the patients' event-related EEG potentials were reduced, reflecting reduced activation of movement preparation, whereas lateralization of the motor cortices (i.e. the lateralized readiness potential) did not differ significantly between groups, reflecting unimpaired response selection. Force and contingent negative variation were generally reduced in the patients showing that their general slowing is at least partially due to impaired activation. Task-specific problems added to the general activation deficit; the lack of modulation of response force by presentation time revealed pronounced deficits of activation in the monotonous clock task. The specific delay of responses with invalidly cued signals, unparalleled by activation measures, might suggest a problem of cognition. The task-specific deficits may reflect a basic dilemma for patients with Parkinson's disease: cognitive problems may arise in complex tasks but disorders of activation may become pronounced in more simple, monotonous tasks.

Adult↗
PubMed1983

[Physiological research and clinical psychiatry. Approach studies].

One of the research approaches followed at the Psychophysiology Unit of the Faculty of Medicine, University of Chile, is described. After clarifying the broad concept of physiology employed in these studies, the notion of behavior is put forward as a function of tre whole living organism. Some reasons for its being neglected in traditional physiological research are briefly presented, along with comments on its relation to clinical work in psychiatry, especially in description and diagnosis. Electrophysiological studies conducted at the Psychophysiology Unit have been aimed at generating data of behavioral relevance during well-defined experimental conditions in order to obtain information complementing that obtained in other observational settings, such as psychometric testing or clinical interview. It is hoped that such approach might be used in the establishment of diagnostic categories of high consensual validity and based on culturefair indicators. As an example of methodical strategy in clinical phychophysiology, work on slow brain potentials (contingent negative variation, CNV) is briefly reviewed.

Behavior↗
PubMed1979

EEG effects of physostigmine and choline chloride in humans.

Seventeen normal volunteers received either 0.5 mg, 1.5 mg, or 2.5 mg physostigmine i.v. in a placebo-drug-placebo single-blind design. EEG was recorded simultaneously and analyzed by computerized spectral analysis. Eleven healthy elderly volunteers (mean age = 69.1 years) with mild memory impairment were treated with placebo, followed by oral choline chloride (either 8 g/day for 3 weeks, or 16 g/day for 1 week), and then, again, placebo. Recordings of spontaneous EEG and EEG event-related potentials (contingent negative variation) were obtained during both placebo and choline treatments. The larger doses of physostigmine produced an increase in low frequency activity and a slowing of the peak alpha frequency. Oral choline chloride had no effect on the EEG as measured by spectral analysis, but appears to have differential effects on contingent negative variation (CNV) amplitude and reaction time, depending upon the initial CNV amplitude.

Adult↗
PubMed2004

Motor processing after movement execution as revealed by evoked and induced activity.

Event-related synchronization (ERS) in the beta frequency band following movement execution has shown that motor processing is not completed yet when a movement ends. It is known that induced and evoked activities reflect different aspects of cortical processing which may result in different time courses. In the current study, we analyzed topography of postimperative negative variation (PINV) in 39 healthy right-handed adolescents in an acoustic forewarned reaction time (contingent negative variation, CNV) task using a 64-electrode high-density sensor array. We dissociated different PINV components in their time course from postmovement beta ERS in order to provide fundamental knowledge about evoked and induced EEG components after movement execution as a basis for further analysis of postmovement processing. A postmovement negativity occurred from about 500 to 1200 ms after the imperative stimulus (peaking about 600 ms after a right-hand button press) at central electrodes, contralateral to the response movement side. Current source density (CSD) analysis confirmed the current sinks over motor areas [contralateral primary motor/premotor and supplementary/cingulate motor area]. The described DC component (motor PINV, mPINV) differed in time course and localization from later "classical" PINV (cPINV) which is thought to reflect contingency reappraisal. mPINV could also be distinguished topographically from a mere delayed CNV resolution. When mPINV and ERS at the same left central electrode were compared, both parameters showed different time courses. Left central mPINV rather paralleled ERS at midcentral electrodes. Therefore, we suggest that the topography of mPINV provides first hints towards an involvement of contralateral primary motor cortex in postmovement processing beyond a mere idling state as reflected by later beta ERS. mPINV could be a useful tool to investigate the role of primary motor cortex in motor-learning processes. The combined analysis of induced and evoked activities seems to be able to elucidate different aspects of cortical connectivity and motor processes following movement.

Acoustic Stimulation↗
PubMedDate not supplied

Endogenous evoked potentials and vigilance levels variations.

The authors consider the possible relationship between the autonomic functions and the contingent Negative Variation (CNV). This relationship has been found both in psychopathological conditions and after the administration of psychotropic drugs. Some preliminary data are reported on the correlations observed between CNV and the autonomic activation (R-R interval) during a sodium lactate infusion.

Arousal↗
PubMed2004

Task-specific sensory and motor preparatory activation revealed by contingent magnetic variation.

The present report studied the magnetic counterpart (CMV) of the auditory contingent negative variation (CNV). The ear where the target auditory stimulus would be presented was cued with a visual central arrow at a validity of 84%. The subject's behavioral response and the magnetoencephalographic (MEG) and electroencephalographic (EEG) signals were recorded. The central cue diminished reaction times (RTs) to the auditory target in the valid conditions with respect to the invalid conditions, indicating that the attentional manipulation was effective. The averaged magnetic field power during the preparatory period was significantly higher than baseline, suggesting the simultaneous presence of a magnetic counterpart of the electric CNV--the CMV. The field maps of the CMV grand averages showed two different and well-established periods: an early one with a magnetic field distribution that suggests a central source, and a late one with a field topography comparable to a low-intensity auditory-evoked field (M1). Single-dipole analysis of the preparatory phase in the subject's magnetic resonance images (MRI) demonstrated the presence of dipolar activity in the posterior cingulate (PCC) and posterior parietal cortices (PPC), superior temporal gyrus (STG) and motor cortices (MC). The lateralization of this activity depended on the orientation of the central cue. These results suggest that the action and perceptual-related areas needed to process the expected subsequent imperative task are recruited during the preparatory periods, influencing the behavioral RTs.

Acoustic Stimulation↗
PubMed1998

Topography of CNV and PINV in schizotypal personality.

The topography of the postimperative negative variation (PINV) was analyzed in participants with high and low scores on the German version of the Schizotypal Personality Questionnaire. Scalp amplitude and Laplacian maps of the terminal contingent negative variation (tCNV) and PINV and the time course of the PINV were compared between the two groups. CNV and PINV were induced with a delayed matching-to-sample task, in which the pattern of the imperative stimulus was either clearly or ambiguous matched to one of the two diamonds simultaneously presented as a warning stimulus 4.0 s earlier. Electroencephalograms were recorded with a DC amplifier (32 channels). Negativity increased from tCNV to PINV, especially at frontal sites, and the PINV was larger under ambiguous than under clear matching conditions. Low-scoring participants showed a right-sided predominance of the PINV, which was absent in high-scoring participants. These results resemble differences in the topography of the PINV between healthy control participants and those with schizophrenia under identical experimental conditions and suggest functional differences between tCNV and PINV.

Adult↗
PubMed1982

Risk-taking and the human bereitschaftspotential.

The effects of response probability and feedback predictability on the human Bereitschaftspotential (BP) were examined in a probability-matching paradigm. The subjects were to guess, by pressing one of two buttons, which of two possible feedback lights could be lighted. The a priori probabilities (30%-70%) of the feedback were known to the subjects. This task was performed both when the feedback was unpredictable and when it was perfectly predictable from the prior information. The BP was enhanced only when the subjects guessed the improbable feedback when it was unpredictable, thereby putting themselves 'at risk.' This effect seemed to be independent of any concurrent contingent negative variation. The results indicate that the BP is sensitive to trial-by-trial variation of the psychological state, which is in some way related to intention.

Adolescent↗
PubMed1975

EEG and neurophysiological studies of early infantile autism.

My aims in this presentation are to review EEG findings that have been published recently in children variously labeled as autistic, schizophrenic, or psychotic. I will also report new results from EEG investigations of an expanded series of Dr. DeMyer's subjects. Sleep research and studies of cerebral evoked responses and the contingent negative variation will be reviewed, and preliminary results of wuantitative analyses of EEG from autistic and normal children will be reported.

Alpha Rhythm↗
PubMed1978

Cortical slow potentials and the occipital EEG in congenital blindness.

In a group of 7 congenitally blind adults, electroencephalographic occipital alpha rhythms were absent, but slow negative cortical potentials (CNV) were recorded over the visual cortex and were similar to those of normally sighted controls. Frontal and central CNV amplitudes, but not auditory evoked potentials or reaction times, were decreased significantly in the blind. The results confirm the presence of a developmental EEG abnormality following early blindness, and demonstrate the independance of slow potential generation from rhythmic 8--12 c/sec EEG activity in deafferented visual cortex. Non-sensory specific, event-related potentials such as the Contingent Negative Variation may prove to be useful psychophysiological probes of residual cortical function in brain regions which are deprived of primary sensory input.

Adult↗
PubMed2000

CNV and temporal uncertainty with 'ageing' and 'non-ageing' S1-S2 intervals.

OBJECTIVES: Uncertainty about the timing of a known external event is an everyday phenomenon but has been rarely investigated with electrophysiological methods. We studied how the amplitude of the contingent negative variation (CNV) is affected by temporal variation of S2 presentation. Competing hypotheses about the development of CNV during the foreperiod until S2 presentation were that CNV either would follow a monotonic trend, be it increasing or decreasing, or alternatively that the time-course of CNV would be affected by the probability with which S2 was presented at each time-point in a given task. METHODS: The interval between cueing stimulus and imperative stimulus was randomly chosen from 3 different values between 1.3 and 2.6 s, using 3 different probability distributions in separate blocks: an 'ageing', a 'non-ageing' and a 'Gaussian' distribution. RESULTS: As previously shown, reaction times were determined by the probability of the imperative stimulus at the given length of the foreperiod. The same was found for CNV amplitude: the effects of temporal uncertainty on CNV mainly depended on the particular distribution of temporal probabilities used in a block. The relevant parameter was the a posteriori probability of event occurrence, very similar to the effects of this parameter on response times. In fact, the major part of the effect of a posteriori probability on CNV was common variation of CNV and response times. CONCLUSIONS: Thus, under temporal uncertainty the amplitude of CNV reflects the subjective expectancies for the occurrence of a given event, with this variation being related to variations in response times.

Adult↗
PubMed1979

A longitudinal CNV study in a group of five bipolar cyclothymic patients.

The authors carried out a longitudinal study in five subjects with bipolar cyclothymic psychosis, recording contingent negative variations in the same patients in the different phases of illness and under normal clinical conditions. An average voltage decrease was found in the depressive phases and a more conspicuous decrease in the manic phases. Furthermore, an evident postimperative negative variation was present in four subjects during the manic phase. The authors set forth tentative psychological and neurophysiological interpretation of their results.

Adult↗