Measurement of extensive auditory discrimination profiles using the mismatch negativity (MMN) of the auditory event-related potential (ERP)

Fast multi-feature paradigm for recording several mismatch negativities (MMNs) to phonetic and acoustic changes in speech sounds

In this study, we addressed whether a new fast multi-feature mismatch negativity (MMN) paradigm can be used for determining the central auditory discrimination accuracy for several acoustic and phonetic changes in speech sounds. We recorded the MMNs in the multi-feature paradigm to changes in syllable intensity, frequency, and vowel length, as well as for consonant and vowel change, and compared these MMNs to those obtained with the traditional oddball paradigm. In addition, we examined the reliability of the multi-feature paradigm by repeating the recordings with the same subjects 1-7 days after the first recordings. The MMNs recorded with the multi-feature paradigm were similar to those obtained with the oddball paradigm. Furthermore, only minor differences were observed in the MMN amplitudes across the two recording sessions. Thus, this new multi-feature paradigm with speech stimuli provides similar results as the oddball paradigm, and the MMNs recorded with the new paradigm were reproducible.

Change detection in newborns using a multiple deviant paradigm: a study using magnetoencephalography

OBJECTIVE

Mismatch responses are elicited to changes in sound streams in healthy newborns. In the ideal case, these responses can predict cognitive problems later in life. We employed a multiple deviant paradigm for a fast assessment of the ability of the newborn brain to respond to various types of acoustic changes.

METHODS

In 12 healthy newborns, we recorded an electroencephalogram (EEG) and magnetoencephalogram while presenting auditory stimuli. Between repeated stimuli, four types of acoustic changes (frequency, intensity, duration, and a gap) were presented, varying in deviance magnitude.

RESULTS

One major response was present in the neonatal evoked potentials and fields at 250-260 ms. Magnetic mismatch responses were elicited to all change types except for the duration deviant and they were positive in polarity. The frequency deviant elicited more positive EEG amplitudes than the standard, whereas the response to the duration deviant was more negative.

CONCLUSIONS

These results show that newborns can detect changes to at least four types of deviances within a sound stream. Furthermore, the use of magneto- and electroencephalography is complementary in newborns, since the methods may reveal different outcomes.

SIGNIFICANCE

Further studies are warranted to determine whether the present study design can play a role in testing auditory function in clinical infant populations.

Hilbert-Huang versus Morlet wavelet transformation on mismatch negativity of children in uninterrupted sound paradigm

BACKGROUND

Compared to the waveform or spectrum analysis of event-related potentials (ERPs), time-frequency representation (TFR) has the advantage of revealing the ERPs time and frequency domain information simultaneously. As the human brain could be modeled as a complicated nonlinear system, it is interesting from the view of psychological knowledge to study the performance of the nonlinear and linear time-frequency representation methods for ERP research. In this study Hilbert-Huang transformation (HHT) and Morlet wavelet transformation (MWT) were performed on mismatch negativity (MMN) of children. Participants were 102 children aged 8-16 years. MMN was elicited in a passive oddball paradigm with duration deviants. The stimuli consisted of an uninterrupted sound including two alternating 100 ms tones (600 and 800 Hz) with infrequent 50 ms or 30 ms 600 Hz deviant tones. In theory larger deviant should elicit larger MMN. This theoretical expectation is used as a criterion to test two TFR methods in this study. For statistical analysis MMN support to absence ratio (SAR) could be utilized to qualify TFR of MMN.

RESULTS

Compared to MWT, the TFR of MMN with HHT was much sharper, sparser, and clearer. Statistically, SAR showed significant difference between the MMNs elicited by two deviants with HHT but not with MWT, and the larger deviant elicited MMN with larger SAR.

CONCLUSION

Support to absence ratio of Hilbert-Huang Transformation on mismatch negativity meets the theoretical expectations, i.e., the more deviant stimulus elicits larger MMN. However, Morlet wavelet transformation does not reveal that. Thus, HHT seems more appropriate in analyzing event-related potentials in the time-frequency domain. HHT appears to evaluate ERPs more accurately and provide theoretically valid information of the brain responses.

Mismatch negativity (MMN) evoked by sound duration contrasts: an unexpected major effect of deviance direction on amplitudes

OBJECTIVE

Verify and explore unexpected results suggesting an effect of deviance direction (shorter or longer deviants) on the amplitude of MMNs evoked by sound duration contrasts.

METHODS

MMNs were recorded using the oddball paradigm on ten adults. Four standard stimulus durations (100, 150, 200 and 250ms) were used and deviants were 50% shorter or longer. Behavioral data (hit rates, d', and reaction times) were collected after the electrophysiological sessions.

RESULTS

MMNs were larger for short than for long deviants. There was no effect on MMN latencies. Hit rates and d' data were almost at ceiling level for all conditions even for the longest standard - long deviant combination in which the MMN was abolished.

CONCLUSIONS

We argue that the deviance direction effect on MMN amplitudes can be explained by the delay between the moment of deviance detection and the end of the deviance quantification process.

SIGNIFICANCE

A major effect of deviance direction on amplitudes was confirmed. This effect, which was confined to electrophysiological data, is to be taken into account when using duration contrasts to probe the processing of temporal information.

Detecting violations of sensory expectancies following cerebellar degeneration: a mismatch negativity study

Two hypotheses concerning cerebellar function and predictive behavior are the sensory prediction hypothesis and the timing hypothesis. The former postulates that the cerebellum is critical in generating expectancies regarding forthcoming sensory information. The latter postulates that this structure is critical in generating expectancies that are precisely timed; for example, the expected duration of an event or the time between events. As such, the timing hypothesis constitutes a more specific form of prediction. The present experiment contrasted these two hypotheses by examining the mismatch negativity (MMN) response in patients with cerebellar cortical atrophy and matched controls. While watching a silent movie, a stream of task-irrelevant sounds was presented. A standard sound was presented 60% of the time, whereas the remaining sounds deviated from the standard on one of four dimensions: duration, intensity, pitch, or location. The timing between stimuli was either periodic or aperiodic. Based on the sensory prediction hypothesis, the MMN for the patients should be abnormal across all four dimensions. In contrast, the timing hypothesis would predict a selective impairment of the duration MMN. Moreover, the timing hypothesis would also predict that the enhancement of the MMN observed in controls when the stimuli are presented periodically should be attenuated in the patients. Compared to controls, the patients exhibited a delayed latency in the MMN to duration deviants and a similar trend for the intensity deviants, while pitch and location MMNs did not differ between groups. Periodicity had limited and somewhat inconsistent effects. The present results are at odds with a general role for the cerebellum in sensory prediction and provide partial support for the timing hypothesis.

On the functional role of temporal and frontal cortex activation in passive detection of auditory deviance

The superior temporal cortex (STC) and inferior frontal cortex (IFC) are active during pre-attentive change detection. According to one influential model, the temporal cortex is responsible for memory trace comparison and the frontal cortex for attention switching. However, fMRI studies that used parametric designs revealed frontal cortex activity that is inconsistent with this model. In response, alternative accounts of frontal cortex activity, such as contrast enhancement and response inhibition, have been suggested. In this study, we measured the event related potential (ERP) and event related optical signal (EROS) responses elicited by pitch deviants in a parametric design. The ERP results revealed the typical modulation of mismatch negativity (MMN) amplitude by degree of deviance. The EROS results showed a similar modulation effect in the temporal cortex and a general temporal cortex followed by frontal cortex activation pattern. Interestingly, medium deviants elicited a greater frontal EROS response than did large or small deviants. Moreover, regression analyses showed that the EROS measures, specifically the linear trend in the temporal cortex and the inverse quadratic trend in the frontal cortex, correlated with the linear trend of the ERP MMN response. Taken together, these results indicate that 1) deviance magnitude modulates the brain activity elicited by pitch stimuli in the STC and IFC within the same time range as electrophysiological measures of passive deviance detection, 2) EROS measures of deviance detection are highly correlated with the ERP MMN, and 3) the functional relationship of STC and IFC is consistent with both the contrast enhancement and response inhibition accounts of IFC activity in passive deviance detection.

The mismatch negativity (MMN) in basic research of central auditory processing: a review

In the present article, the basic research using the mismatch negativity (MMN) and analogous results obtained by using the magnetoencephalography (MEG) and other brain-imaging technologies is reviewed. This response is elicited by any discriminable change in auditory stimulation but recent studies extended the notion of the MMN even to higher-order cognitive processes such as those involving grammar and semantic meaning. Moreover, MMN data also show the presence of automatic intelligent processes such as stimulus anticipation at the level of auditory cortex. In addition, the MMN enables one to establish the brain processes underlying the initiation of attention switch to, conscious perception of, sound change in an unattended stimulus stream.

MMN or no MMN: no magnitude of deviance effect on the MMN amplitude

Based on results showing that the "deviant-minus-standard" estimate of the mismatch negativity (MMN) amplitude increases with increasing amounts of deviance, it has been suggested that the MMN amplitude reflects the amount of difference between the neural representations of the standard and the deviant sound. However, the deviant-minus-standard waveform also includes an N1 difference. We tested the effects of the magnitude of deviance on MMN while minimizing this N1 confound. We found no significant magnitude of deviance effect on the genuine MMN amplitude. Thus we suggest that the average MMN amplitude does not reflect the difference between neural stimulus representations; rather it may index the percentage of detected deviants, each of which elicits an MMN response of uniform amplitude. These results are compatible with an explanation suggesting that MMN is involved in maintaining a neural representation of the auditory environment.

Audiovisual Events in Sensory Memory

The functional properties of the auditory sensory memory have been extensively studied using the mismatch negativity (MMN) component of the auditory event-related potential (ERP) and its magnetic counterpart recorded using magneto-encephalography (MEG). It has been found that distinct auditory features (such as frequency or intensity) are encoded separately in sensory memory. Nevertheless, the conjunction of these features (auditory “gestalts”) can also be encoded in auditory sensory memory. Here we investigated how auditory and visual features of bimodal events are represented in sensory memory by recording audiovisual MMNs in two different audiovisual oddball paradigms. The results of a first ERP experiment showed that the sensory memory representations of auditory and visual features of audiovisual events lie within the temporal and occipital cortex, respectively, yet with possible interactions between the processing of the unimodal features. In a subsequent MEG experiment, we found some evidence that audiovisual feature conjunctions could also be represented in sensory memory. These results, thus, extend to the audiovisual domain a number of properties of sensory memory already established within the auditory system.

The Mismatch Negativity

In the present article, I will selectively review some of the recent research on the brain substrates of central-auditory processing using the mismatch negativity (MMN) and its magnetoencephalographic equivalent MMNm, trying to identify some of the most promising trends in this research work. Although the early MMN research dealt almost exclusively with basic cognitive-neuroscience issues, more recently, the usefulness of the MMN phenomenon with regard to a large number of clinical and other applied issues has also been realized. Nine research lines or issues with particular promise will be identified, many of which are of a clinical/applied nature. Cognitive brain research using the MMN, an automatic electric response to any discriminable change in auditory stimulation, has continued for three decades and seems continuously to gain in number, inspired by novel findings, there now being approximately 1,000 articles in English-language international journals using, or referring to, the MMN. There are several highly promising research lines or issues: (1) the MMN as an index of early cognitive development, (2) the MMN as an index of the functional condition of the NMDA-receptor system, (3) the MMN as an index of the different brain pathologies underlying schizophrenia, (4) the role of the MMN in genetic research of psychopathology, (5) the extremely wide range of MMN deficiency across different clinical conditions and diseases, (6) the MMN in prediction of coma outcome, (7) the MMN as an index of primitive sensory intelligence in audition, and (8) the MMN as an index of brain mechanisms of speech perception and understanding. These findings, in particular (8), extend the interpretation of the MMN, currently mainly confined to sensory representations, to involve auditory memory in general.