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Results for “Contingent Negative Variation”

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At least 1,387 records · Page 77Linked to original sources
PubMed1988

Cardiovascular, electrocortical, and behavioral effects of nicotine chewing gum.

The cardiovascular, electrocortical, and behavioral effects of orally administered nicotine during rapid information processing were assessed in deprived female smokers. In a pre-post treatment design, 10 subjects received a 4-mg nicotine chewing gum and 10 subjects a placebo. The mental task required the subjects to watch single digits presented in a pseudorandom order on a screen and to press a button whenever the last three digits were either odd or even. The presentation rate decreased after each error and increased after each correct response and was used as the index of performance. Event-related brain potentials (ERP) to each of the three digits of the correctly answered triads were analyzed. The ERPs showed a distinct CNV potential for the second digit only (expectancy) and a P300 response for the third digit only (response decision). The mean EEG power spectrum was computed for each 5-min resting period, set before each trial and at the end of the session. A single administration of 4-mg nicotine chewing gum was followed by heart rate increase, acrodermal vasoconstriction, increase in theta and alpha frequency, decrease in delta power, and increase in the CNV magnitude. However, the chewing gum neither increased performance or reaction time nor decreased any ERP latencies or amplitudes, as has been reported after cigarette smoking.

Adolescent↗
PubMed1977

EEG and evoked potential approaches to the study of neuropeptides.

EEG and event related potential (ERP) phenomena were considered here from the standpoint of possible applications to investigations of the central effects of neuropeptides in man. These electrophysiological phenomena were viewed from the standpoint that they provide an accessible intermediate level of observation between behavior and detailed neuronal events. Several general methodological issues were discussed. An attempt was made to describe the EEG and ERP phenomena that may be pertinent to future neuropeptide studies and to consider their functional significance. Available data concerning electrophysiological effects of neuropeptides were also discussed. Suggestions for future research were made, which emphasized comprehensive recording of EEG and ERP phenomena to permit examination of the patterning of electrocerebral events.

Acoustic Stimulation↗
PubMed1988

[Changes in various activation indices as a function of the value given by a stimulus in anhedonic and deprossogenic subjects].

The aim of this experiment was to investigate, in "normal" subjects, the relationship between personality characteristics (anhedonia and depressogenic attitudes) and various tonic and phasic activation indices (EEG power spectra, CNV (at Fz and Cz), heart rate and reaction time) recorded during auditory stimulations, and the influence of the affective value of stimuli on phasic activation indices. Eighteen subjects were divided into two opposite groups according to their scores on two self-rating questionnaires (the Chapman Physical Anhedonia Scale and the Beck-Weissman Dysfunctional Attitude Scale): the A group (anhedonic with depressogenic attitudes) and the H group (hedonic and non-depressogenic). The experiment was divided into three phases. The first and third phase utilised an identical classical CNV paradigm. During the second phase, two of the three neutral warning tones of the first phase were given, by conditioning, a positive or a negative value. The results showed that: 1) before conditioning, when all stimuli were neutral, all activation indices (tonic and phasic) were significantly higher in the A group than in the H group; 2) after conditioning, the two groups differed mainly by their cortical reactivity to the positively conditioned sound: the amplitude of the two CNV components increased in the H group whereas a tendency to a CNV decrease was seen in the A group; 3) all the between-group CNV differences were significant only at Fz. These results were discussed in terms of differences of optimal level of activation.

Acoustic Stimulation↗
PubMedDate not supplied

Event-related potentials and autonomic functions.

The authors pointed out how some of the anatomic structures involved in the genesis of the event related potentials (ERPs) are also considered parts of the supranuclear regulation apparatus of the autonomic nervous system. Since there are evident functional similarities between some components of the ERPs and the orienting reflex--primitive form of attention--that is clearly associated with an autonomic activation, it could be interesting to evaluate the parameters of the ERPs in those experimental and clinical situations in which there is a functional involvement of the vegetative nervous system.

Autonomic Nervous System↗
PubMed1987

Slow negative potential shifts indicating verbal cognitive learning in a concept formation task.

It is well-known clinically that patients with left frontal lesions are impaired in their verbal-cognitive learning ability. Starting from such observations, it is of particular interest whether the event-related cerebral potential shifts recorded in healthy human subjects would indicate a left frontal lobe involvement in verbal-cognitive learning tasks. In a concept formation paradigm, subjects learned by trial and error to transform letters into Morse codes. This cognitive performance was accompanied by a slow negative potential shift (SP) that in frontal recordings was lateralized towards the left hemisphere. off results show in a later stage of learning, in which the experience of the preceding trial and error learning could be integrated, an increasing slow negativity over the frontal cortex. Ss also participated in a control task with already known letter/Morse code combinations. Again, a negative potential shift occurred within the stimulus-response interval, however, it was smaller in amplitude.

Adult↗