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 1,135 records · Page 63Linked to original sources
PubMed1998

Mismatch negativity: deviance detection or the maintenance of the 'standard'.

Electric brain responses were measured to infrequent tones that broke the frequency alternation of two tones, deviated in duration or violated both regularities (alternation and constant duration). Mismatch negativity (MMN) was elicited by both simple deviants with the duration-related MMN peaking approximately 130 ms later than the alternation-related MMN. The double deviant elicited two successive MMNs. Thus violation of each regularity elicited a separate MMN, whereas previous studies showed that multiple temporally separate deviations from a single repetitive standard elicit one MMN only. These results suggest that the primary function of the MMN-generating process is more closely related to maintaining the representation of auditory regularities than to deviance detection per se.

Acoustic Stimulation↗
PubMed1999

The functional anatomy of the McCollough contingent colour after-effect.

We report two functional magnetic resonance imaging (fMRI) experiments which reveal a cortical network activated when perceiving coloured grids, and experiencing the McCollough effect (ME). Our results show that perception of red-black and green-black grids activate the right fusiform gyrus (area V4) plus the left and right lingual gyri, right striate cortex (V1) and left insula. The ME activated the left anterior fusiform gyrus as well as the ventrolateral prefrontal cortex, and in common with colour perception, the left insula. These data confirm the critical role of the fusiform gyrus in actual and illusory colour perception as well as revealing localized frontal cortical activation associated with the ME, which would suggest that a 'top-down' mechanism is implicated in this illusion.

Adult↗
PubMed2004

Does familiarity facilitate the cortical processing of music sounds?

Automatic cortical sound discrimination, as indexed by the mismatch negativity (MMN) component of the auditory evoked potential, is facilitated for familiar speech sounds (phonemes). In musicians as compared to non-musicians, an enhanced MMN has been observed for complex non-speech sounds. Here, musically trained subjects were presented with sequences of either familiar (tonal) or structurally matched unfamiliar (atonal) triad chords, both with either fixed or randomly transposed chord root pitch. The MMN elicited by deviant chords did not differ for familiar and unfamiliar triad sequences, and was undiminished even to unfamiliar deviant sounds which were consciously undetectable. Only subsequent attention-related components indicated facilitated cognitive processing of familiar sounds, corresponding to higher behavioral detection scores.

Acoustic Stimulation↗
PubMed2005

Auditory event-related potentials as a function of abstract change magnitude.

Event-related potentials were recorded in healthy volunteers to test the accuracy of the human brain to extract, preattentively, auditory abstract rules. The abstract rule was determined by the frequency relationship between two pure tones forming a pair. The standard pairs had identical tone frequency, whereas the deviant pairs had the second tone two, four, six or eight musical steps higher or lower in frequency than the first one. All abstract changes elicited mismatch negativity, which was not affected by the magnitude of change. However, the subsequent P3a increased as a function of the magnitude of the abstract change. These results suggest that mismatch negativity detects violations of abstract rules, and the amount of violation is analyzed in subsequent stages of auditory processing.

Acoustic Stimulation↗
PubMed2005

Audiovisual phonological mismatch produces early negativity in auditory cortex.

During silent reading, visual information provided by letters is converted to auditory information in the mind. The purpose of this study was to identify the primary locus for auditory verbal imagery in the brain. Neuromagnetic recording was obtained from 10 right-handed study participants, who were instructed to identify infrequently occurring phonological mismatches between a random-ordered sequence of syllable sounds and a visually presented syllabogram sequence. The activity difference in early latency, calculated by subtracting the averaged responses to matched syllables from the averaged responses to mismatched syllables, showed a spatiotemporal profile strikingly similar to that of mismatch negativity. Auditory imagery of forthcoming verbal sounds may establish a memory trace as a template for imagery-based mismatch negativity generation in the auditory cortex.

Acoustic Stimulation↗
PubMed2005

Auditory imagery mismatch negativity elicited in musicians.

A mismatch between auditory sensation and expectant imagery of syllables elicited a possible equivalent of mismatch negativity in a previous study. The purpose of this study was to verify whether auditory imagery from musical notation could also mediate such imagery-based mismatch negativity. Neuromagnetic recording was obtained from eight musicians, who were instructed to identify unpredictably occurring pitch mismatches between a random tone sequence and a visually presented musical score. The difference between incongruent and congruent responses showed a magnetic distribution consistent with two frontal-negative current dipoles bilaterally located in the vicinity of Heschl's gyrus, peaking at approximately 150 ms in latency. This imagery-based mismatch negativity may represent an early neural process of deviance detection between the sensory input and expectant imagery.

Acoustic Stimulation↗
PubMed1998

Early potentials of direct cortical responses: experimental study in dogs and pathophysiological and clinical implications.

OBJECTIVE: The characteristics of the early component of the direct cortical response have not been well studied, although direct cortical response recording is a common method of brain function monitoring. METHODS: In this experimental study, we sought conditions affording the clearest recording of the early potential, by varying the polarity and low-cutoff filter setting, and we confirmed that the early potential consists of two components, P1 and P2. RESULTS: When subcortical damage was induced by local cerebral compression or saline injection, transient changes in P1 and permanent disappearance of P2 were observed. P2 also disappeared when the fiber connections between the cortex and the basal ganglia, including the thalamus, were destroyed by wire insertion. With deep recording, both P1 and P2 exhibited potential reversal at a level histologically confirmed to be in Layer V of the cortex. CONCLUSION: These findings suggest that P1 is a spike reflecting the activity of pyramidal cells evoked by electrical stimulation of the brain surface and that P2 is a potential arising in Layer V of the cortex and is related to afferent fibers from the thalamus. Recording of P2 may be useful for monitoring for subcortical damage.

Animals↗
PubMed1978

Event-related slow potential (ERSP) correlates of thyroid gland function level.

This study shows an association between thyroid gland function level and event-related slow brain potential (ERSP) parameters (peak amplitude and area under the curve), obtained during "classical" and "operant" reaction-time paradigms. A significant positive correlation between ERSP parameters and 24-hr I131 uptake and a negative nonsignificant one between them and ankle jerk reflex were found. Organismic factors related to thyroid function had greater influence upon ERSP amplitude and area than situational ones, for no significant effect of task was evidenced and no interaction between them was found under the conditions employed. Hyper- and hypothyroids showed also a tendency to present longer reaction times than euthyroids. These results are discussed within the framework of the arousal-distraction coupling hypothesis as proposed by Tecce and Cole (1976) and compared to those previously obtained in high-neuroticism anxiety-prone indivuduals. Although these and hyperthyroids do show indications of similar behavioral manifestations (excessive reactive arousal), both groups are considered to differ regarding empirical referennts of anticipatory arousal (ERSP parameters). A major difference seems to be the absence of a "ceiling effect" in hyperthyroids. This hypothetical phenomenon can be expected on the basis of the inverted U-shaped relation between ERSP amplitude and arousal level. A stronger "distraction" effect associated with increased arousal in anxiety neurotics is postulated and tentatively attributed to covert verbalizations of worry and feelings added to increased awareness of autonomic input. The contention is advanced that similar behavioral manifestations could be distinguishable at the physiological level employed and this might add further insights to diagnostic typologies (e.g., "psychosomatic" vs. "psychoneurotic" patients).

Adult↗
PubMed2003

Auditory evoked potentials from the cortex: audiology applications.

PURPOSE OF REVIEW: The audiological applications of cortical auditory evoked potentials are reviewed. Cortical auditory evoked potentials have some advantages compared with more commonly used techniques such as the auditory brainstem response, because they are more closely tied to perception and can be evoked by complex sounds such as speech. These response characteristics suggest that these potentials could be used clinically in the estimation of threshold and also to assess speech discrimination and perception. RECENT FINDINGS: Clinical uses of auditory evoked potentials include threshold estimation and their use as an electrophysiological index of auditory system development, auditory discrimination and speech perception, and the benefits from cochlear implantation, auditory training, or amplification. SUMMARY: Cortical auditory evoked potentials obtained in passively alert adults have a remarkably high correspondence with perceptual threshold. Acoustic features of complex sounds may be reflected in the waveform and latency of these potentials and so might be used to determine the integrity of neural encoding for such features and thus contribute to speech perception assessment. MMN and P3 have been used to discern discrimination abilities among groups of normal-hearing and hearing-impaired individuals; however, their sensitivity and specificity for testing an individual's abilities has not yet been established. Cortical auditory potentials are affected by listening experience and attention and so could be used to gauge the effects of aural habilitation. The presence of cortical potentials in children with auditory neuropathy appears to indicate residual hearing abilities. Parametric and developmental research is needed to further establish these applications in audiology.

Audiology↗
PubMed2005

Brain potentials to sexually suggestive whistles show meaning modulates the mismatch negativity.

Electroencephalographic data suggest that spoken words produce an enhanced output of the brain's automatic deviance detection system, as reflected by the mismatch negativity. Using meaningful and nonmeaningful whistles, we sought to distinguish the effect of semantic content on the brain's deviance detection system from language-specific stimulus features. In the meaningful condition, study participants heard a human 'wolf whistle', which is commonly interpreted as an unsolicited expression of sexual attention. In the nonmeaningful condition participants heard an acoustically identical, but digitally rearranged, version of the wolf whistle. The mismatch negativity amplitude was significantly larger when the infrequent stimulus was meaningful than when it was meaningless. These data suggest that enhanced mismatch negativity magnitude was due to the semantic valence of the eliciting deviant.

Acoustic Stimulation↗
PubMed2005

Phoneme quality and quantity are processed independently in the human brain.

In speech perception, the primary cue of phoneme recognition is typically the spectral quality of the speech sound. In some languages, however, even speech-sound duration may serve as a phonological cue. This distinction is called quantity. We used a component of event-related potential, the mismatch negativity, to determine whether phoneme quality and quantity are processed independently in the human brain. We found that the mismatch negativity responses to phoneme quality and quantity changes are additive, indicating that the analysis of these features is independent of each other. This suggests that phoneme quality and quantity are processed by separate neural processes that, in a system model, may be regarded as different levels in the phonological system.

Acoustic Stimulation↗
PubMed2005

Infants' electric brain responses to emotional prosody.

In the current study, we examined 7-month-old infants' processing of emotional prosody using event-related brain potentials. Infants heard semantically neutral words that were spoken with either a happy, angry, or neutral voice. The event-related brain potential data revealed that angry prosody elicited a more negative response in infants' event-related potentials than did happy or neutral prosody, suggesting greater allocation of attention to angry prosody. A positive slow wave was elicited by angry and happy prosody over temporal electrode sites. This indicates an enhanced sensory processing of the emotionally loaded stimuli (happy and angry). The current findings demonstrate that very early in development, the human brain detects emotionally loaded words and shows differential attentional responses depending on their emotional valence.

Acoustic Stimulation↗
PubMed2006

Affective context-induced modulation of the error-related negativity.

The error-related negativity putatively reflects the activity of performance-monitoring processes influenced by motivational factors, and is overactive in certain anxiety states, suggesting that affective factors affect its generation. We examined the effects of emotionally arousing and neutral task-irrelevant backgrounds on the error-related negativity to determine whether an affective context 'mismatch' alters error-related neural processing. Event-related potentials were acquired while healthy participants performed a modified Eriksen flanker task wherein flanker stimuli were superimposed on neutral, pleasant, and unpleasant pictures. The error-related negativity varied as a function of picture valence, peaking both earlier and larger in the context of pleasant backgrounds than neutral or unpleasant backgrounds. Findings support the hypothesis that affective factors influence the error-related negativity, potentially reflecting an affective mismatch associated with performance monitoring.

Adult↗
PubMed2006

Phonetic mismatch negativity predicts verbal memory deficits in schizophrenia.

Deficits in auditory sensory memory at the electrophysiological level as indexed by mismatch negativity and those in auditory verbal memory at the neuropsychological level have been independently demonstrated in previous studies of schizophrenia. We predicted a specific association between these indices in schizophrenia. Mismatch negativities elicited by change in tone duration and phoneme duration were recorded in 23 schizophrenia patients, who were also evaluated for auditory verbal memory and executive function. Lower amplitude of mismatch negativity under the phoneme-duration condition was significantly associated with worse verbal memory. Phoneme-duration mismatch negativity was not correlated with executive function, nor was tone-duration mismatch negativity correlated with verbal memory. These results suggest that electrophysiological auditory sensory memory dysfunction underlies the basis for neuropsychological auditory verbal memory deficits in schizophrenia.

Adult↗
PubMed2006

Impaired duration mismatch negativity in developmental dyslexia.

A mismatch negativity event-related potential protocol was administered to dyslexic children and their respective controls to test whether a specific auditory deficit concerning phonetic processing or a lower level auditory processing deficit was present in developmental dyslexia. Three different contrast conditions were explored, including nonphonological sounds, contrasted in pitch and duration, and phonemes. Mismatch negativity amplitudes differed significantly between groups in the duration condition, whereas no differences were found in the frequency and phoneme conditions. Moreover, the dyslexic children had delayed mismatch negativity latencies in the three contrast conditions. Our results suggest a deficit in low-level auditory discrimination in dyslexic children, in particular when detecting stimulus duration, and support the rapid auditory processing theory of dyslexia.

Acoustic Stimulation↗
PubMed2006

Visual mismatch negativity highlights abnormal preattentive visual processing in Alzheimer's disease.

Mismatch negativity has been found to decline in amplitude with increasing age and also in Alzheimer's disease. It has been suggested that the reduction in amplitude of mismatch negativity in Alzheimer's disease is the result of fatigue rather than a generalized decline in neuronal response. We tested this hypothesis by measuring the effect of time on task on the visual mismatch negativity in both normal aging and in Alzheimer's disease. In older adults, visual mismatch negativity showed a reduction in amplitude, which did not vary with time on task. This argues against fatigue as the cause of visual mismatch negativity amplitude reduction in normal ageing. In Alzheimer's disease, visual mismatch negativity was virtually absent in responses to the first 16 deviant stimuli but present in response to subsequent deviants. This is opposite to the effect predicted by the fatigue hypothesis. It suggests that individuals with Alzheimer's disease are initially refractory to stimulus change.

Adult↗
PubMed2006

Is there a mismatch negativity during change blindness?

The mismatch negativity is an event-related potential that represents a preattentive change detection process. The aim of this study was to determine whether the mismatch negativity was present during 'change blindness', a striking phenomenon in which surprisingly large changes in a complex scene are not seen when they occur during a blink or an eye movement. In this study, large orientation changes elicited a candidate mismatch negativity between 180 and 320 ms that appeared to be independent of participants' performance (uncued 76% correct, miscued 59% correct with chance performance at 50%). This negativity, however, disappeared in the miscued 'change blind' condition. In conclusion, the mismatch negativity does not appear to be present during change blindness suggesting that in complex scenes even large changes may not trigger preattentive change detection processes.

Acoustic Stimulation↗