Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Contingent Negative Variation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources

The effects of self-movement, observation, and imagination on mu rhythms and readiness potentials (RP's): toward a brain-computer interface (BCI).

Current movement-based brain-computer interfaces (BCI's) utilize spontaneous electroencephalogram (EEG) rhythms associated with movement, such as the mu rhythm, or responses time-locked to movements that are averaged across multiple trials, such as the readiness potential (RP), as control signals. In one study, we report that the mu rhythm is not only modulated by the expression of self-generated movement but also by the observation and imagination of movement. In another study, we show that simultaneous self-generated multiple limb movements exhibit properties distinct from those of single limb movements. Identification and classification of these signals with pattern recognition techniques provides the basis for the development of a practical BCI.

Adult↗

Comparing arithmetic and semantic fact retrieval: effects of problem size and sentence constraint on event-related brain potentials.

Event-related potentials were recorded with 61 electrodes from 16 students who verified either the correctness of single-digit multiplication problems or the semantic congruency of sentences. Multiplication problems varied in size and sentence fragments in constraint. Both semantic and arithmetic incongruencies evoked a typical N400 with a clear parieto-central maximum. In addition, numerically larger problems (8x7), in comparison to smaller problems (3x2), evoked a negativity starting at about 360 ms whose maximum was located over the right temporal-parietal scalp. These results indicate that the arithmetic incongruency and the problem-size effect are functionally distinct. It is suggested that the arithmetic and the semantic incongruency effects are both functionally related to a context-dependent spread of activation in specialized associative networks, whereas the arithmetic problem-size effect is due to rechecking routines that go beyond basic fact retrieval.

Attention↗

The error-related negativity as a state and trait measure: motivation, personality, and ERPs in response to errors.

This study examines changes in the error-related negativity (ERN/Ne) related to motivational incentives and personality traits. ERPs were gathered while adults completed a four-choice letter task during four motivational conditions. Monetary incentives for finger and hand accuracy were altered across motivation conditions to either be equal or favor one type of accuracy over the other in a 3:1 ratio. Larger ERN/Ne amplitudes were predicted with increased incentives, with personality moderating this effect. Results were as expected: Individuals higher on conscientiousness displayed smaller motivation-related changes in the ERN/Ne. Similarly, those low on neuroticism had smaller effects, with the effect of Conscientiousness absent after accounting for Neuroticism. These results emphasize an emotional/evaluative function for the ERN/Ne, and suggest that the ability to selectively invest in error monitoring is moderated by underlying personality.

Adolescent↗

The intractability of scaling scalp distributions to infer neuroelectric sources.

ERP researchers use differences in scalp distributions to infer differences in spatial configurations of neuroelectric generators. Since McCarthy and Wood (1985) demonstrated that a spatially fixed current source varying only in strength can yield a significant Condition x Electrode interaction in ANOVA, the recommended approach has been to normalize ERP amplitudes, for example, by vector length, prior to testing for interactions. The assumptions of this procedure are examined and it is shown via simulations that this application of vector scaling is both conceptually flawed and unsound in experimental practice. Because different spatial configurations of neural generators cannot reliably be inferred from different scalp topographies even after amplitude normalization, it is recommended that the procedure no longer be used for this purpose.

Analysis of Variance↗

Memory-based detection of task-irrelevant visual changes.

Colored grating patterns were presented to 8 participants in a passive oddball condition (standard, 87.5% and deviant, 12.5%, differing in their color). In the corresponding multicolor condition, grating patterns of eight different colors were presented, their probabilities set equal both to each other and to that of the deviant in the oddball task. Compared with the ERP response elicited by the standard stimulus, the deviant response was negatively displaced over posterior areas, the difference wave peaking at 136 ms. A similar negative wave was obtained when the ERP response to the deviant was compared with the ERP elicited by the same stimulus in the multicolor condition. This result rules out stimulus- (color-) specific refractoriness as a major factor in the generation of the deviance-related posterior negativity. The observed posterior negativity can therefore be regarded as a visual analog of the mismatch negativity (vMMN).

Adolescent↗

Neural signals for the detection of unintentional race bias.

We examined the hypothesis that unintentional race-biased responses may occur despite the activation of neural systems that detect the need for control. Participants completed a sequential priming task that induced race-biased responses on certain trials while electroencephalography was recorded. The error-related negativity (ERN) wave, a component of the event-related potential with an anterior cingulate generator, was assessed to index neural signals detecting the need for control. Responses attributed to race bias produced larger ERNs than responses not attributed to race bias. Although race-biased responses were prevalent across participants, those with larger ERNs to race-biased responses showed higher levels of control throughout the task (e.g., greater accuracy and slowed responding following errors). The results indicate that race-biased responses may be made despite the activation of neural systems designed to detect bias and to recruit controlled processing.

Arousal↗

The seed and the soil: effect of dosage, personality and starting state on the response to delta 9 tetrahydrocannabinol in man.

1 The effects of two doses of delta 9THC (2.5 and 10 mg), delivered by paced smoking of herbal cigarettes, on CNV magnitude, subjective mood ratings and heart rate were studied in 20 subjects. 2 There were highly significant interactions between drug dosage and Extraversion and Neuroticism scores, so that the direction and degree of response to the different doses of delta 9THC depended on the personality characteristics of the subjects. 3 The effects of 9 mg delta 9THC and placebo, delivered in herbal cigarettes smoked naturally, on smoking behaviour, subjective mood ratings, measures of autonomic activity and auditory and visual cortical evoked responses were compared in 12 subjects. 4 Smoking behaviour, subjective 'high' rating and elevation of heart rates were the most significant discriminators between drug and placebo. The latency of some of the components of the visual evoked responses was also increased by delta 9THC. 5 There was a significant correlation between the effects of delta 9THC on skin conductance reactivity and the basal (pre-drug) level, reactivity increasing after drug in subjects with low basal reactivity and decreasing in those with high basal levels. 6 Both experiments provided clear evidence of dose-dependent biphasic stimulant and depressant actions of delta 9THC on both subjective and objective measures, and these effects were influenced by the personality and the starting state of the subjects.

Cannabis↗

Recovery of CNV area after nonresponse condition: inverted-U relation with arousal.

The effect of motor-response recovery after a nonresponse condition on the CNV was investigated in relation to the MPI in 53 healthy adults. The control CNV area before the nonresponse condition had an inverted-U relation to the extraversion score. At the recovery condition the inverted-U relation between the CNV area and the extraversion score shifted toward the lower extraversion score in those subjects who showed a shortened reaction time: i.e., the introverts, particularly the dysthymiacs, responded with the larger CNV area at the recovery condition than at the control condition. These results suggest that the dysthymiacs who possibly have obsession and depression are at a high arousal level and compel attention to a repetitive event as habituating.

Adult↗

Slow negative potentials during problem-solving.

Electroencephalographic changes by solving mathematical problems were tested on 52 healthy young subjects. Slow negative potentials appeared in the frontal lobe (Fz) when the subject was asked to add numerals presented by a slide projector, multiply them and add them while hearing other addition problems through headphones. The mean amplitude of the potential was larger in multiplication and in addition while hearing other addition problems than in addition.

Adolescent↗

Melancholia and excessive CNV recovery after nonresponse condition.

The effect of nonresponse on the Cz-CNV recovery was studied in 13 depressed patients on the hypothesis that the excessive CNV recovery had a relation to melancholia. The depressed patients had a significantly small Control CNV area before the nonresponse as compared with a matched group of healthy controls. The dysthymic patients by the Maudsley Personality Inventory (MPI) showed a significantly smaller Control CNV area than the non-dysthymic patients. Melancholic patients who met the DSM-III criteria had a significantly longer control reaction time and more excessive CNV recovery than the non-melancholics. The excessive CNV recovery is useful as a predictor for melancholia, and the motivational facilitation and preparatory motor inhibition underlying the psychomotor retardation and hence "endogenous process" were discussed.

Adult↗

A negative component on event related potential recorded in the drowsy state.

Behavior of event related potential (ERP) components in the drowsy state was examined in nine subjects using oddball paradigm. A component with peak latency of 300 msec, N300, was superimposed on ERP in the drowsy state. N300 appeared also in stage 1 of NREM sleep and closely resembled vertex sharp wave evoked by sound stimulation in both scalp distribution and peak latency. It was suggested that N300 recorded in the drowsy state and vertex sharp wave recorded in stage 1 of NREM sleep are generated by the identical synchronizing mechanism in the brain.

Adult↗

Similarities in the phenotype of the auditory neural substrate in children with Asperger syndrome and their parents.

Asperger syndrome (AS) is a developmental disorder of brain function characterized by deficits in social interaction including difficulties in understanding emotional expressions. Children with AS share some of the behavioural characteristics with their parents and AS seems to run particularly in the male members of the same families. The aim of the present study was to determine whether similarities could be found between children with AS and their parents at central auditory processing. It was found that in children with AS the sound encoding, as reflected by the exogenous components of event-related potentials, was similarly abnormal as in both their mothers and fathers. However, their abnormal cortical auditory discrimination, as indexed by the prolonged latency of the mismatch negativity, resembled that of their fathers but not that of their mothers. The present results suggest that complex genetic mechanisms may contribute to auditory abnormalities encountered in children with AS.

Acoustic Stimulation↗

The sound of actions as reflected by mismatch negativity: rapid activation of cortical sensory-motor networks by sounds associated with finger and tongue movements.

In order to explore the activation dynamics of the human action recognition system, we investigated electrophysiological distinctions between the brain responses to sounds produced by human finger and tongue movements. Of special interest were the questions of how early these differences may occur, and whether the neural activation at the early stages of processing involves cortical motor representations related to the generation of these sounds. For this purpose we employed a high-density EEG set-up and recorded mismatch negativity (MMN) using a recently developed novel multideviant paradigm which allows acquisition of a high number of trials within a given time period. Deviant stimuli were naturally recorded finger and tongue clicks, as well as control stimuli with similar physical features but without the clear action associations (this was tested in a separate behavioural experiment). Both natural stimuli produced larger MMNs than their respective control stimuli at approximately 100 ms, indicating activation of memory traces for familiar action-related sounds. Furthermore, MMN topography at this latency differed between the brain responses to the natural finger and natural tongue sounds. Source estimation revealed the strongest sources for finger sounds in centrolateral areas of the left hemisphere, suggesting that hearing a sound related to finger actions evokes activity in motor areas associated with the dominant hand. Furthermore, tongue sounds produced activation in more inferior brain areas. Our data suggest that motor areas in the human brain are part of neural systems subserving the early automatic recognition of action-related sounds.

Acoustic Stimulation↗

Electrophysiological markers of voice familiarity.

Our ability to discriminate and recognize human voices is amongst the most important functions of the human auditory system. The current study sought to determine whether electrophysiological markers could be used as objective measures of voice familiarity, by looking at the electrophysiological responses [mismatch negativity (MMN) and P3a] when the infrequent stimulus presented is a familiar voice as opposed to an unfamiliar voice. Results indicate that the MMN elicited by a familiar voice is greater than that elicited by an unfamiliar voice at FCz. The familiar voice also produced a greater P3a wave than that triggered by the unfamiliar voice at Fz. As both the MMN and the P3a were elicited as participants were instructed not to pay attention to incoming stimulation, these findings suggest that voice recognition is a particularly potent preattentive process whose neural representations can be objectively described through electrophysiological assessments.

Acoustic Stimulation↗

Spatial location is accurately tracked by human auditory sensory memory: evidence from the mismatch negativity.

The nature of spatial representation in human auditory cortex remains elusive. In particular, although humans can discriminate the locations of sounds as close as 1-10 degrees apart, such resolution has not been shown in auditory cortex of humans or animals. We used the mismatch negativity (MMN) event related brain potential to measure the neural response to spatial change in humans in narrow 10 degree spatial steps. Twelve participants were tested using a dense array EEG setup while watching a silent movie and ignoring the sounds. The MMN was reliably elicited by infrequent changes of spatial location of sounds in free field. The MMN amplitude was linearly related to the degree of spatial change with a resolution of at least 10 degrees. These electrophysiological responses occurred within a window of 100-200 milliseconds from stimulus onset, and were localized to the posterior superior temporal gyrus. We conclude that azimuthal spatial displacement is rapidly, accurately and automatically represented in auditory sensory memory in humans, at the level of the auditory cortex.

Acoustic Stimulation↗

Phonological but not auditory discrimination is impaired in dyslexia.

Deficient phonological skills are considered to be a core problem in developmental dyslexia. Children with dyslexia often demonstrate poorer performance than non-impaired readers when categorizing speech-sounds. Using the automatic mismatch response, we show that in contrast to this deficit at the behavioural level, neurophysiological responding in dyslexic children indicates their ability to automatically discriminate syllables. Therefore, the phonological deficit is unlikely to be caused by a temporal deficit or by a noisy functional organization in the respective representational cortex. We obtained measures of reading, spelling and categorical speech-perception from 58 dyslexic children and 21 control children. The children also participated in magnetoencephalographic measurements while being stimulated acoustically with the syllables /ba/ and /da/ in an oddball paradigm. Mismatch field (MMF) amplitudes between standard and deviant stimuli were obtained. Dyslexic children performed more poorly than control children on all test measures. However, the groups did not differ in MMF amplitude or latency. No correlations were found between MMF amplitudes and behavioural performance. These results were obtained with a large sample size and thus speak robustly against a general deficit in auditory discrimination in dyslexia. These results are compatible with the idea that decoding difficulties occur later in the processing stream where access to the phonological lexicon is attempted.

Auditory Perception↗

Localizing cortical sources of event-related potentials in infants' covert orienting.

This study used cortical source analysis to locate potential cortical sources of event-related potentials (ERPs) during covert orienting in infants aged 14 and 20 weeks. The infants were tested in a spatial cueing procedure. The reaction time to localize the target showed response facilitation for valid trials relative to invalid or neutral trials. High-density EEG (126 channels) was recorded during the task, and independent component analysis and equivalent current dipole analysis was used to estimate the cortical sources of the EEG during the task. There was a larger P1 ERP component on the valid trials than the other trials (P1 validity effect). The cortical source analysis suggested that this occurred due to activity in Brodmann's areas 18 and 19. A presaccadic ERP component occurred over the frontal scalp areas (-65 ms) and was larger to a target in a cued location than in uncued locations. A potential cortical source for this ERP component was the superior frontal gyrus on the inferior portion of the prefrontal cortex. Increases from 14 to 20 weeks in amplitude of the P1 validity effect and the presaccadic ERP could be modeled by an increase in activation in the corresponding cortical areas.

Age Factors↗