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Results for “Contingent Negative Variation”

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PubMed1997

Bereitschaftpotential in schizophrenia.

BACKGROUND: Several reports have documented the presence of motor abnormalities in schizophrenic patients. METHOD: Thirty schizophrenics and 28 healthy controls were included in the study. Scalp-recorded bereitschaftpotentials (BPs) generated prior to voluntary movements were recorded in all subjects. RESULTS: The early (NSI) and late components of BP and peak negativity were reduced in all schizophrenic patients. In particular, the NSI was reduced in patients with positive symptoms, and the late component in patients with negative symptoms. CONCLUSIONS: These findings provide further support of the involvement of frontal cortex, subcortical structures and their connections in schizophrenia, and highlight some differences between positive and negative symptom clusters.

Adult↗
PubMed2006

Error-related electrocortical responses are enhanced in children with obsessive-compulsive behaviors.

The error-related negativity (ERN or Ne) and positivity (Pe) are event-related potential components elicited during simple discrimination tasks after an error response. The ERN and Pe have a fronto-central scalp distribution and may be an indirect measure of anterior cingulate (AC) activity as it relates to performance monitoring. Brain imaging studies suggest that obsessive-compulsive disorder (OCD) is associated with exaggerated activity of the AC while electrophysiological studies have found an association between OCD and pronounced ERNs in adults. The present study explored the relation between obsessive-compulsive behaviors, the ERN, and the Pe in a sample of nonclinical 10-year-old children. It was found that more parent-reported obsessive-compulsive behaviors were associated with larger ERN and Pe components in the children. Results suggest unique contributions of the ERN and Pe in predicting obsessive-compulsive behaviors.

Anxiety↗
PubMed2005

Effect of practice on brain activity: an investigation in top-level rifle shooters.

PURPOSE: The study investigated the effect of motor experience on the brain activity associated with self-paced movement of the left and right index fingers. METHOD: Movement-related cortical potentials (MRCP) are indices of cortical activation related to movement preparation and execution. MRCP were recorded in two groups of subjects: high-level rifle shooters and control subjects without any shooting experience. All subjects were right-handed. Four MRCP components were considered: Bereitschaftspotential (BP), negative slope (NS'), motor potential (MP), and reafferent positivity (RAP). The BP and NS' components, which emerged before movement onset, were associated with preparation for voluntary movements. RESULTS: Differences between groups were found in the amplitude and latency of these components for right finger flexion (but not for left finger flexion). BP and NS' latencies were longer for shooters than for controls; amplitudes were smaller. In contrast, no difference was found between groups for MP and RAP amplitude or latency. Source analysis, based on a realistic model of the brain, showed with high reliability (97/% of variance explained) that the BP (time window: -1500 400 ms), NS' (-400 50 ms), MP (0 +100 ms) and RAP (+100 +200 ms) components were generated in the supplementary motor area, premotor area, primary motor area, and somatosensory area, respectively. No difference was found between groups regarding the localization of generators of all components. CONCLUSION: Results are discussed in terms of neural economy of motor preparation due to the specific practice involved in shooting.

Adaptation, Physiological↗
PubMed1988

Acute effects of ethanol on motor performance and movement-related brain potentials.

The acute effects of ethanol on skilled motor functions were examined in male social drinkers, under four doses ranging from 0 (placebo) to 1.05 g/kg lean body weight. The movement entailed a forewarned choice transitive motion of the arm and hand, aimed at a flanking target. Performance measures disclosed only small effects of ethanol on speed and accuracy of movement. The simultaneously-recorded movement-related brain potentials disclosed decreased involvement of frontal and posterior brain areas, suggesting that ethanol disrupted the planning and regulation of movement despite the overall preservation of reaction speed.

Contingent Negative Variation↗
PubMed2005

Event-related brain potential correlates of human auditory sensory memory-trace formation.

The event-related potential (ERP) component mismatch negativity (MMN) is a neural marker of human echoic memory. MMN is elicited by deviant sounds embedded in a stream of frequent standards, reflecting the deviation from an inferred memory trace of the standard stimulus. The strength of this memory trace is thought to be proportional to the number of repetitions of the standard tone, visible as the progressive enhancement of MMN with number of repetitions (MMN memory-trace effect). However, no direct ERP correlates of the formation of echoic memory traces are currently known. This study set out to investigate changes in ERPs to different numbers of repetitions of standards, delivered in a roving-stimulus paradigm in which the frequency of the standard stimulus changed randomly between stimulus trains. Normal healthy volunteers (n = 40) were engaged in two experimental conditions: during passive listening and while actively discriminating changes in tone frequency. As predicted, MMN increased with increasing number of standards. However, this MMN memory-trace effect was caused mainly by enhancement with stimulus repetition of a slow positive wave from 50 to 250 ms poststimulus in the standard ERP, which is termed here "repetition positivity" (RP). This RP was recorded from frontocentral electrodes when participants were passively listening to or actively discriminating changes in tone frequency. RP may represent a human ERP correlate of rapid and stimulus-specific adaptation, a candidate neuronal mechanism underlying sensory memory formation in the auditory cortex.

Acoustic Stimulation↗
PubMed2004

Neuromagnetic analysis of the late phase of the readiness field for precise hand movements using magnetoencephalography.

The aim of this study was to elucidate the cortical regulation of precise finger movements by using magnetoencephalography, with particular emphasis on the late phase of the readiness field. Magnetic brain signals were recorded non-invasively by 306 channel magnetoencephalography during the following two tasks. The first task, a simple task, was to bend the right thumb once as quickly as possible. The second task, a precise one, was to alternately oppose the thumb with the index finger and the middle finger of right hand. In this study, we confirmed that the differences between the two tasks were observed in the late phase of the readiness field, especially in the magnetic field 600 ms before the onset of movement. The activity of the magnetic field of the precise movement task was higher than the activity of the simple movement task. There were obvious differences in the spatial and temporal aspects of the left hemisphere. In the simple movement, the premotor area or motor area was activated in the late phase of the time window. The average latency from the EMG onset was -98.6+/-34.0 ms (n = 5). In the precise movement, the prefrontal area and the SMA were activated in the early and/or middle phases of the time window. The average latency from the EMG onset was -292.0+/-14.9 ms (n = 3) for the prefrontal cortex and -167.8+/-38.3 ms (n = 4) for the SMA. The premotor area or motor area was activated in the late stage of the RF. The average latency from the EMG onset was -111.6+/-61.4 ms (n = 5). Many studies have been performed on the movement-related readiness field. However, the activity of the prefrontal area and the SMA had not previously been studied in the late phase of the readiness field. Our study indicated that the prefrontal area and the SMA played important roles immediately before the onset of precise finger movement. The integration of the prefrontal area, the SMA, and the premotor area is important for the onset of precise finger movement.

Adult↗
PubMed1987

Changes in central somatosensory pathways accompanying reaction movements.

The changes within central somatosensory pathways accompanying reaction movements were examined by subtracting the peak latency of the major response from the cervical area (14 msec.) from that of the primary cortical response (20 msec.) and also measuring the CNV which is dependent on the direction of the subject's attention and level of arousal. These parameters were measured before (at rest), during fast and slow reaction movements, and mental readiness to act. Analysis showed that the difference in N20-N14 potential latencies is the shortest during fast reaction movements and is shorter during movement tasks than during mental readiness and intention to act. Moreover, we confirmed that the CNV amplitudes are significantly higher during fast than during slow reaction movements and also that the difference in N20-N14 potential latencies decreases as the CNV amplitude increases. Accordingly, from the present results and a series of studies conducted by others, it may be concluded that not only are the changes in the central motor area confirmed by the movement-associated cerebral potentials but also those in the central somatosensory area occur prior to reaction movements.

Adult↗
PubMed2000

Automatic auditory processing and event-related brain potentials in persons with mental retardation.

Measuring event-related brain potentials, this study examined automatic auditory processing in adults with and without mental retardation. Using an auditory oddball paradigm under an inattentive condition, we anticipated that an enhanced negative potential would be followed by a relatively small positive potential. The former was considered as the mismatch negativity and the latter as the P3a. Retarded adults (1 woman, 6 men, defined as a range of moderate to profound retardation) and 8 nonretarded (2 women, 6 men) adults participated. The mismatch negativity showed smaller amplitudes and greater latencies for retarded persons than those for nonretarded adults, whereas the P3a for the groups was comparable. The results may suggest malfunction of automatic auditory change-detection of the brain in mentally retarded persons.

Adult↗
PubMed2002

Reactivity and event-related potentials in attentional tests: effect of training.

To study the effects of training on reactivity and event-related potentials a complex attentional shifting test involving reaction time was administered (Test 1) to 24 healthy, young students. After five days, 12 subjects were tested with the same procedure (Test 2) without training (Untrained Subjects) while 12 repeated the test at the fifth day after four days of training (Trained Subjects). During Tests 1 and 2, event-related potentials were recorded by electroencephalogram. The task consisted of each subject responding to a stimulus of a letter appearing in the centre of a geometric figure on the screen of a computer monitor. In the prestimulus period black points were drawn and crowded randomly into a zone of the screen. The geometric figure and the letter were shown in the centre of the crowding. There were two letters and four geometric figures randomly combined in different ways. The subject had to press different keys of the computer keyboard when specific combinations appeared. The averaged event-related potentials were characterized by a negative wave with a close relationship to selective attention before the onset of the stimulus of a geometric figure followed by letters. After the stimulus onset, a P3 complex was recorded. Trained subjects were no different from untrained subjects in Test 1, while in Test 2 they had a shorter reaction time, an earlier peak of the selective attention related wave and P3, and a higher amplitude for the P3 complex. These measures and the correlations between them can be considered an index of the training effect. Thus, these tests could be used for evaluation of the attentional style and its modification with training.

Adult↗
PubMed1980

Correlation between steady potential baseline and event-related slow potential magnitude in the rat.

Event-related slow potential (SP) responses to a warning stimulus were recorded from rat frontal and visual cortex during performance of a reaction-time task. Measurements of steady potential baseline and magnitude of the negative SP response were obtained for individual trials (presented at variable intervals). The correlation between baseline and SP response magnitude was examined utilizing both amplitude and integrated area data. Also, averaged SP responses were obtained by selecting trials for averaging according to baseline potential. Slow potential response magnitude was inversely correlated with baseline negativity. Neither baseline nor SP response amplitude was correlated with trial number of intertrial interval. Averaged SP responses consisting of trials with more positive baselines were larger in magnitude than averaged SP responses consisting of trials with more negative baselines. The steady potential level attained during trials with more positive baselines was not more negative than the level reached during trials with negative baselines. These data are consistent with the concept of "ceiling" effect for event-related slow potentials.

Animals↗