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Results for “Contingent Negative Variation”

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At least 1,477 records · Page 82Linked to original sources
PubMed1982

Extraversion and inhibition: a slow-potential study.

This report presents data showing that extroverts (Eysenck Personality Inventory) develop larger positive vertex slow potentials than introverts under extinction conditions ("no go" instruction in a fixed foreperiod reaction time task). The effect was clearer in subjects with low neuroticism (N) scores than in those with a middle N level. Since independent evidence indicates that cortical positivity is associated with inhibitory phenomena, results are interpreted as lending support to the notion that extroverts may develop more inhibitory potential than introverts under certain conditions.

Adult↗
PubMedDate not supplied

[Interhemispheric functional relationships in negative human emotions].

11 right-handed subjects with normal vision were examined. The analysis of latencies and amplitudes of the late AEP components elicited by verbal stimuli, presented in different halves of the visual field, revealed that the late positive evoked potential P300 to a single word with neutral meaning develops in the right occipital area with a shorter latency and a greater amplitude, than in the left one. Interhemispheric differences are not observed in "the associative" zone (presumably at the junction of the temporal, parietal and occipital areas). In the process of perception of an emotional word interhemispheric relations are considerably changed: in the left occipital area the P300 wave latency is considerably shorter, than in the right one; no differences in the amplitude of P300 are visible. The changes in P300 wave latencies reflect a local nonspecific activation of the cortex, directly connected with the analysis of the emotional verbal signal. The obliteration of interhemispheric differences in P300 wave amplitude is largely due to background emotional excitation.

Adolescent↗
PubMed1980

[Status and prospects for physiologic research in psychiatry].

The author discusses the three principles of higher nervous activity (determinism, analysis and synthesis, attachment of dynamics to the structure) formulated by I. P. Pavlov and their theoretical significance in the studies of physiological bases of mental disorders. The modern conditioned reflexectory and electrophysiological methods for studying higher nervous activity of normals and mentally ill patients are analyzed. The significance of studies in the field of physiological bases of mental disorders for the application of pathogenetically founded therapy is discussed as well as for the natural scientific understanding of mental phenomena in health and disease from the aspect of determinism.

Brain↗
PubMed1978

[Studies of the expectancy wave (CNV) in patients with interruption of the thalamo-prefrontal interconnnection pathways caused by psychosurgical prefrontal lobotomy operations].

Frontal and vertex CNVs were studied in 8 selected nonschizophrenic patients subjected to unilateral or bilateral extensive prefrontal lobotomy. The dorsomedial thalamo-frontal pathways had been severed and their regeneration must be considered impossible. Standard CNV task (S1-S2-R) was followed in order to elicit CNVs from the frontal areas anterior to the line of sections and at Cz. In 7 out of 8 patients it was quite easy to evoke CNV with almost normal features and equal latencies in each case from all the cortical areas explored. These results show that CNV formation is not grossly altered in the prefrontal areas which have been irreversibly deprived of normal bi-directional mediothalamic-frontocortical connnections. This suggests that the role of the dorsomedial thalamo-frontal pathways are not essential in the genesis of the frontal CNV in humans. These findings would suggest that the CNV is a diffuse electrical event essentially related to a unitary cerebral process mediated fundamentally by nonspecific ascending meso-diencephalic reticular systems. The differences in morphology and polarity of the CNVs detectable in various brain structures are presumably related to their intrinsic anatomo-functional characteristics and to the method commonly utilized in recording the CNV.

Adult↗
PubMedDate not supplied

[Hemispheric asymmetry of the P300 wave to unrecognized emotional words].

The wave P300 was recorded in both hemispheres in order to study interhemispheric differences in the process of perception of unrecognized verbal stimuli. The stimuli--unrecognized words, neutral and emotional--were alternately presented at random in the left and right visual fields. In response to an unrecognized emotional word, the amplitude of the P300 wave increases diffusely in both hemispheres, as compared to the response to a neutral word, with no changes in interhemispheric differences. They change considerably in the process of an "unaccountable" emotion, caused by an unrecognized word, due to unilateral activation of the right hemisphere. The conclusion is made on the predominant role of the right hemisphere in the cortical organization of such unconscious function as "unaccountable" emotion.

Adolescent↗
PubMedDate not supplied

[Interhemispheric functional relations during formation of temporary connections in humans].

In the course of formation of temporary connection between a nonverbal visual stimulus and an emotional word, interhemispheric functional relations are significantly changed. The conditioned stimulus elicits local activation mainly in the visual cortex of the left hemisphere, which results in reversion of interhemispheric relations during latency of cortical evoked response. In the "associative" area, the elaboration of the temporary connection does not affect latency and amplitude of the evoked response to the conditioned stimulus. Extinction of the temporary connection and, hence, recovery of the interhemispheric functional relations observed before its elaboration, proceeds slowly, and sets in after 100-150 presentations of the signal without reinforcement.

Adult↗
PubMed1995

[The characteristics of endogenous evoked potentials during normal psychomotor reactions and during basal ganglionic dysfunction in man].

Averaged cortical EPs (or the ERPs) in response to light stimuli were analysed in the Fz, Pz and Oz leads in healthy subjects and in Parkinsonian patients. The largest CNV and Nd (negative difference) were recorded in the Fz, the negative waves being inversely related to each other. A delay in psychomotor responses was accompanied by a decrease in the endogenous ERPs in all the leads in Parkinsonian patients. The ERp attenuation seems to be connected with the cortical hypoactivation due to the basal ganglia disfunction.

Basal Ganglia↗
PubMed1995

Individual differences in slow brain potentials in a guessing task.

18 healthy right-handed subjects had to predict one of two random non-equiprobable events by pressing one of two buttons with the right index finger. Each trial was preceded by a cue that increased the probability of the corresponding event in comparison to its overall probability. The Bereitschaftspotential (BP) before an action and the stimulus-preceding negativity (SPN) between the action and the event presentation were recorded. The subjects were subdivided into groups according to their tendency to follow the cue or to reject it. Cue rejection provided in the present situation a larger final gain than cue acceptance. Those subjects who used the former strategy were characterized by a local BP increase over the right parietal cortex, when a low-probable cue was presented. Their SPN amplitude was relatively small, but it increased substantially after a low-probable cue. Subjects who tended to follow the cue had a very large BP amplitude over the projection area and at vertex. Their SPN was overall large, regardless of condition. Peculiarities of the potentials recorded in these subjects are thought to relate to their desire to minimize errors.

Adolescent↗