Search results for "MISMATCH NEGATIVITY"
showing 10 items of 182 documents
Empirical Mode Decomposition on Mismatch Negativity
2008
Empirical mode decomposition (EMD) has been applied in the various disciplines to extract the desired signal. The basic principle is to decompose a time series into intrinsic mode functions (IFMs) and each IFM corresponds to an oscillation phenomenon. A statistical description of the oscillatory activities of the EEG has been well known. It is desired to extract single oscillatory process from the EEG by EMD. Mismatch negativity (MMN) can be automatically elicited by the deviant stimulus in an oddball paradigm, in which physically the deviant stimulus occurs among repetitive and homogeneous stimuli. MMN thus reflects the ability of the brain to detect changes in auditory stimuli. So, the MM…
Extract Mismatch Negativity and P3a through Two-Dimensional Nonnegative Decomposition on Time-Frequency Represented Event-Related Potentials
2010
This study compares the row-wise unfolding nonnegative tensor factorization (NTF) and the standard nonnegative matrix factorization (NMF) in extracting time-frequency represented event-related potentials—mismatch negativity (MMN) and P3a from EEG under the two-dimensional decomposition The criterion to judge performance of NMF and NTF is based on psychology knowledge of MMN and P3a MMN is elicited by an oddball paradigm and may be proportionally modulated by the attention So, participants are usually instructed to ignore the stimuli However the deviant stimulus inevitably attracts some attention of the participant towards the stimuli Thus, P3a often follows MMN As a result, if P3a was large…
Somatosensory mismatch response in young and elderly adults
2014
Aging is associated with cognitive decline and alterations in early perceptual processes. Studies in the auditory and visual sensory modalities have shown that the mismatch negativity [or the mismatch response (MMR)], an event-related potential (ERP) elicited by a deviant stimulus in a background of homogenous events, diminishes with aging and cognitive decline. However, the effects of aging on the somatosensory MMR (sMMR) are not known. In the current study, we recorded ERPs to electrical pulses to different fingers of the left hand in a passive oddball experiment in young (22–36 years) and elderly (66– 95 years) adults engaged in a visual task. The MMR was found to deviants as compared to…
Linguistic multifeature MMN paradigm for extensive recording of auditory discrimination profiles
2011
We studied whether a multifeature mismatch negativity (MMN) paradigm using naturally produced speech stimuli is feasible for studies of auditory discrimination accuracy of adult participants. A naturally produced trisyllabic pseudoword was used in the paradigm, and MMNs were recorded to changes that were acoustic (changes in fundamental frequency or intensity) or potentially phonological (changes in vowel identity or vowel duration). All the different changes were presented in three different word segments (initial, middle, or final syllable). All changes elicited an MMN response, but the vowel duration change elicited a different response pattern than the other deviant types. Changes in vo…
Children with dyslexia reveal abnormal native language representations: Evidence from a study of mismatch negativity
2011
Although a deficit perceiving phonemes, as indexed by the mismatch negativity (MMN), is apparent in developmental dyslexia (DD), studies have not yet addressed whether this deficit might be a result of deficient native language speech representations. The present study examines how a native-vowel prototype and an atypical vowel are discriminated by 9-year-old children with (n 5 14) and without (n 5 12) DD. MMN was elicited in all conditions in both groups. The control group revealed enhanced MMN to the native-vowel prototype in comparison to the atypical vowel. Children with DD did not show enhanced MMN amplitude to the native-vowel prototype, suggesting impaired tuning to native language s…
Event-related potentials to task-irrelevant changes in facial expressions
2009
Abstract Background Numerous previous experiments have used oddball paradigm to study change detection. This paradigm is applied here to study change detection of facial expressions in a context which demands abstraction of the emotional expression-related facial features among other changing facial features. Methods Event-related potentials (ERPs) were recorded in adult humans engaged in a demanding auditory task. In an oddball paradigm, repeated pictures of faces with a neutral expression ('standard', p = .9) were rarely replaced by pictures with a fearful ('fearful deviant', p = .05) or happy ('happy deviant', p = .05) expression. Importantly, facial identities changed from picture to pi…
ERPs to pitch changes: a result of reduced responses to standard tones in rabbits.
1996
EVENT-RELATED potentials (ERPs) were recorded in rabbits when pitch deviant tones occurred in a series of standard tones (oddball situation). In control recordings, the deviant tones were presented without the standard tones (deviant-alone situation). In the oddball situation, significant difference ERPs (deviant ERPs - standard ERPs) could be found in the hippocampal and cerebellar recordings but not in the visual cortex. All the ERPs to the deviant stimuli observed in the oddball situation were also present in the deviant-alone situation. The difference ERPs were therefore based on reduced responses to the standards. The results are discussed in the context of a mismatch negativity (MMN) …
Detrimental noise effects on brain's speech functions.
2009
Background noise has become part of our everyday life in modern societies. Its presence affects both the ability to concentrate and communicate. Some individuals, like children, the elderly, and non-native speakers have pronounced problems in noisy environments. Here we review evidence suggesting that background noise has both transient and Sustained detrimental effects on central speech processing. Studies on the effects of noise on neural processes have demonstrated hemispheric reorganization in speech processing in adult individuals during background noise. During noise, the well-known left hemisphere dominance in speech discrimination became right hemisphere preponderant. Furthermore, l…
Deviance detection in sound frequency in simple and complex sounds in urethane-anesthetized rats
2019
Mismatch negativity (MMN), which is an electrophysiological response demonstrated in humans and animals, reflects memory-based deviance detection in a series of sounds. However, only a few studies on rodents have used control conditions that were sufficient in eliminating confounding factors that could also explain differential responses to deviant sounds. Furthermore, it is unclear if change detection occurs similarly for sinusoidal and complex sounds. In this study, we investigated frequency change detection in urethane-anesthetized rats by recording local-field potentials from the dura above the auditory cortex. We studied change detection in sinusoidal and complex sounds in a series of …