Do tone duration changes that elicit the mismatch negativity also affect the preceding middle latency responses?

The human brain can automatically detect sound changes. Previous studies have reported that rare sounds presented within a sequence of repetitive sounds elicit the mismatch negativity (MMN) in the absence of attention in the latency range of 100–250 ms. On the other hand, a previous study discovered that occasional changes in sound location enhance the middle latency response (MLR) elicited in the latency range of 10–50 ms. Several studies have reported an increase in the amplitude of the MLR within the frame of oddball paradigms such as frequency and location changes. However, few studies have been conducted on paradigms employing a duration change. The purpose of the present study was to examine whether the peak amplitudes of the MLR components are enhanced by a change in duration. Twenty healthy Japanese men (age: 23.9 ± 2.9 years) participated in the present study. We used an oddball paradigm that contained standard stimuli with a duration of 10 ms and deviant stimuli with a duration of 5 ms. The peak amplitudes of the MLR for the deviant stimuli were then compared with those for the standard stimuli. No changes were observed in the peak amplitude of the MLR resulting from a duration change, whereas a definite MMN was elicited. The amplitude of the MLR was increased within the frame of oddball paradigms such as frequency and location changes. By contrast, the amplitude of the MLR was not changed within the duration change oddball paradigm that elicited the MMN.     

Measuring duration mismatch negativity.

OBJECTIVE: Automatic comparisons of sound duration in auditory sensory memory are typically investigated by comparing event-related potentials (ERPs) to standard and deviant stimuli presented in oddball blocks. Deviants elicit mismatch negativity (MMN). This procedure might overestimate an MMN contribution reflecting automatic sensory memory processes because of differential states of refractoriness of respectively recruited neural populations [Neuroreport 1996;7:3005; Psychophysiology 2001;38:723]. Here, memory-comparison-based Duration MMN contributions were investigated using various experimental protocols. METHODS: Memory-comparison-based first-order Duration MMN was investigated using 4 blocked conditions: (a) descending Deviant (100 ms, P=0.14), 150 ms Standard; (b) reverse ascending Deviant (150 ms), 100 ms Standard; (c) Control comprised of 7 equiprobable durations between 25 and 175 ms; and additionally (d) equiprobable tones between 100 and 400 ms. Using the former 3 conditions, Deviants, Standards and Controls were physically identical. RESULTS: Comparing Deviants and Controls excluded potential refractoriness effects, and a decomposition of memory-comparison-based MMN and residual MMN was demonstrated. Genuine Duration MMN was also obtained in the deviant-standard-reverse comparison. CONCLUSIONS: Using a blocked control condition yielded equivalent results to reversing the role of deviant and standard in two separate oddball blocks. Using the reverse ascending deviant condition is thus sufficient as a control.     

Top-down modulation of auditory processing: effects of sound context, musical expertise and attentional focus

By recording auditory electrical brain potentials, we investigated whether the basic sound parameters (frequency, duration and intensity) are differentially encoded among speech vs. music sounds by musicians and non-musicians during different attentional demands. To this end, a pseudoword and an instrumental sound of comparable frequency and duration were presented. The accuracy of neural discrimination was tested by manipulations of frequency, duration and intensity. Additionally, the subjects' attentional focus was manipulated by instructions to ignore the sounds while watching a silent movie or to attentively discriminate the different sounds. In both musicians and non-musicians, the pre-attentively evoked mismatch negativity (MMN) component was larger to slight changes in music than in speech sounds. The MMN was also larger to intensity changes in music sounds and to duration changes in speech sounds. During attentional listening, all subjects more readily discriminated changes among speech sounds than among music sounds as indexed by the N2b response strength. Furthermore, during attentional listening, musicians displayed larger MMN and N2b than non-musicians for both music and speech sounds. Taken together, the data indicate that the discriminative abilities in human audition differ between music and speech sounds as a function of the sound-change context and the subjective familiarity of the sound parameters. These findings provide clear evidence for top-down modulatory effects in audition. In other words, the processing of sounds is realized by a dynamically adapting network considering type of sound, expertise and attentional demands, rather than by a strictly modularly organized stimulus-driven system.     

Neurophysiological evidence of impaired musical sound perception in cochlear-implant users

Objective

Music perception with a cochlear implant (CI) can be unsatisfactory because current-day implants are primarily designed to enable speech discrimination. The present study aimed at evaluating electrophysiological correlates of musical sound perception in CI users to help achieve the long-term goal of improved restoration of hearing in those individuals.

Methods

Auditory discrimination accuracy in adult CI users (n = 12) and matched normal-hearing controls (n = 12) was measured by behavioral discrimination tasks and mismatch negativity (MMN) recordings. Discrimination profiles were obtained by using a set of clarinet sounds (original/vocoded) varying along different acoustic dimensions (frequency/intensity/duration) and deviation magnitudes (four levels).

Results

Behavioral results and MMN recordings revealed reduced auditory discrimination accuracy in CI users. An inverse relationship was found between MMN amplitudes and duration of profound deafness.

Conclusions

CI users have difficulties in discriminating small changes in the acoustic properties of musical sounds. The recently developed multi-feature MMN paradigm (Pakarinen et al., 2007) can be used to objectively evaluate discrimination abilities of CI users for musical sounds.

Significance

Measuring auditory discrimination functions by means of a multi-feature MMN paradigm could be of substantial clinical value by providing a comprehensive profile of the extent of restored hearing in CI users.     

Involuntary attention in children as a function of sound source location: evidence from event-related potentials.

OBJECTIVES: The present study addressed the question of whether location of the auditory stimulation source affects an involuntary attention triggering to the deviant sounds in a passive oddball paradigm in 8-10-year-old children. METHODS: Using free-field stimulation two late event-related potentials components were examined: the mismatch negativity (MMN), indexing preconscious sound change detection and the P3a, indexing involuntary attention switch. Data were registered to frequency changes in sounds of different complexities in two experimental conditions. In the 'in-front' condition, the sound sequences were presented through the loudspeakers situated in front of a participant on both sides of the video display. In the 'on-sides' condition, the sources of auditory and visual stimuli were separated by moving the loudspeakers to the sides of the participant. RESULTS: The MMN amplitude or the MMN and P3a latencies varied in neither stimulus class significantly as a function of sound location. However, significantly larger P3 amplitude was found in the 'in-front', as compared to the 'on-sides' condition. CONCLUSIONS: The present results indicate enhanced involuntary attention switching in children when unattended auditory events occur within the space attended actively for visual modality. Such study design favouring cross-modal integration can be advantageous when studying involuntary auditory attention and its impairment in children.     

Language-specific memory traces of consonants in the brain

This study examined whether experience with a native language affected processing of a place-of-articulation feature. In Experiment 1, 10 stimuli from a continuum of synthesized Hindi bilabial, dental and retroflexed stops were presented to English and Hindi speakers to examine discrimination and identification across the bilabial/dental and dental/retroflexed boundaries. In an oddball task designed to elicit mismatch negativity (MMN), subjects ignored these stimuli while their brain activity was recorded. All participants showed similar behavioral discrimination and identification. However, the English subjects were slower that the Hindi subjects on the discrimination task. All subjects were less accurate and slower at identifying and discriminating the dental and retroflexed compared to the bilabial sounds. A small MMN was observed for some of the bilabial-dental contrasts, but not for the dental-retroflexed contrasts. No group differences were found. In Experiment 2, MMN was observed to a greater stimulus difference (bilabial-retroflexed) and was earlier when the bilabial rather than the retroflexed sound served as the frequent stimulus for both groups. The MMN was also earlier for the Hindi than the English groups when the retroflexed sound served as the frequent stimulus. These results indicate that the Hindi speakers used detailed acoustic-phonetic information for more rapid brain discrimination than the English participants and that the dental-retroflexed discrimination is more difficult than the bilabial-dental discrimination for all speakers.     

Pre-attentive and attentive processing of temporal and frequency characteristics within long sounds

Attention effects on the processing of deviations in the duration and the frequency dimension of a long sound were investigated in three conditions: (1) when auditory stimuli were ignored, (2) when they were attended and frequency dimension was task-relevant, and (3) when they were attended and duration dimension was task-relevant. The mismatch negativity (MMN) of the event-related potential (ERP) to infrequent shortenings of a sound (600 ms vs. 1000 ms) and to infrequent frequency modulations at one of nine possible intervals within the sound (change from 440 Hz to 480 Hz and back to 440 Hz, e.g. in the 600-650 ms interval) was measured. Duration MMN was slightly enhanced when directing attention towards the frequency dimension but notably enhanced when attention was focused on duration. The early phase of frequency-modulated MMN was of equal amplitude in all three conditions, and the late phase was equally enlarged in both attend conditions. Interestingly, MMN to frequency-modulated deviants decreased the later the deviation occurred within the sound; there was no indication for an MMN being present in Ignore condition when frequency modulations occurred 400 ms after sound onset or later. Thus, with increasing temporal distance between the onset of a sound and the onset of a deviation within the sound (e.g. frequency modulation or sound offset), MMN for frequency modulations and duration shortenings decreases. This suggests that the initial part of a sound ( approximately 300 ms) contributes more to the unitary sound representation underlying MMN than the later parts.     

Parameter-specific modulation of the mismatch negativity to duration decrement and increment: Evidence for asymmetric processes

ObjectiveThe mismatch negativity (MMN) component of event-related potentials (ERPs) reflects a change-detection process in the brain. The present study investigated whether stimulus parameters (sound type and duration) exert a differential influence on the MMN for a duration decrement and increment of an equal magnitude. Some asymmetries were reported in the previous studies; yet no systematical study has been conducted.MethodsERPs were recorded from 16 healthy adults presented with repetitive standard sounds interspersed with duration changes (deviant sounds). In separate sequences, stimuli were vowels, music chord, sinusoid, or band-pass filtered white noise. The stimulus durations (standard/deviant) were either 200/120 ms or 400/240 ms for decrements, and vice versa for increments.ResultsThe MMN for the increments was abolished in the 400/240 ms condition, whereas the MMN for decrements was significant irrespective of the sound duration. The amplitude of the increment MMN paralleled with the spectral complexity of the stimulus sound, whereas that of the decrement MMN was larger for natural sounds than artificial sounds.ConclusionsThe observed interactions demonstrated asymmetries in the MMN for duration increment and decrement.SignificanceThe present findings suggest that the effects of stimulus parameters should be taken into account when comparing different studies, especially where clinical populations are involved, with one another.     

Temporal processing ability is related to ear-asymmetry for detecting time cues in sound: a mismatch negativity (MMN) study

Temporal and spectral sound information is processed asymmetrically in the brain with the left-hemisphere showing an advantage for processing the former and the right-hemisphere for the latter. Using monaural sound presentation we demonstrate a context and ability dependent ear-asymmetry in brain measures of temporal change detection. Our measure of temporal processing ability was a gap-detection task quantifying the smallest silent gap in a sound that participants could reliably detect. Our brain measure was the size of the mismatch-negativity (MMN) auditory event-related potential elicited to infrequently presented gap sounds. The MMN indexes discrimination ability and is automatically generated when the brain detects a change in a repeating pattern of sound. MMN was elicited in unattended sequences of infrequent gap-sounds presented among regular no-gap sounds. In Study 1, participants with low gap-detection thresholds (good ability) produced a significantly larger MMN to gap sounds when sequences were presented monaurally to the right-ear than to the left-ear. In Study 2, we not only replicated a right-ear-advantage for MMN in silence in good temporal processors, but also showed that this is reversed to a significant left-ear-advantage for MMN when the same sounds are presented against a background of constant low-level noise. In both studies, poor discriminators showed no ear-advantage, and in Study 2, exhibited no differential sensitivity of the ears to noise. We conclude that these data reveal a context and ability-dependent asymmetry in processing temporal information in non-speech sounds.     

Auditory discrimination profiles of speech sound changes in 6-year-old children as determined with the multi-feature MMN paradigm

ObjectiveA linguistic multi-feature mismatch negativity (MMN) paradigm with five types of changes (vowel, vowel-duration, consonant, frequency (F0), and intensity) in Finnish syllables was used to determine speech-sound discrimination in 17 normally-developing 6-year-old children. The MMNs for vowel and vowel-duration were also recorded in an oddball condition in order to compare the two paradigms. Similar MMNs in the two paradigms would suggest that they tap the same processes. This would promote the usefulness of the more time-efficient multi-feature paradigm for future studies in children.MethodsMMNs to five deviant types were recorded in the multi-feature paradigm in which these deviants (total of 50%) were presented in an alternating fashion with standards (50%). An oddball condition with vowel and vowel-duration deviants served as a control.ResultsThe linguistic multi-feature paradigm elicited significant MMN responses to all changes used and the responses were comparable to the ones recorded with the traditional oddball paradigm. Compared to a previous adult study (Pakarinen S, Lovio R, Huotilainen M, Alku P, Näätänen R, Kujala T. Fast multi-feature paradigm for recording several mismatch negativities (MMNs) to phonetic and acoustic changes in speech sounds. Biol Psychol, submitted for publication), the MMN amplitudes seemed to be smaller and of longer latencies in general in children than in adults.ConclusionsThe new time-efficient paradigm can be used in studies addressing cortical speech-sound discrimination in young children.SignificanceThe multi-feature paradigm enables fast (20 min) recording of MMNs for five speech-sound features. In future, it might be useful in detecting abnormalities in speech discrimination profiles of children with possible language-related disorders.     

Mismatch negativity of higher amplitude for melodic ascendance than descendance

The auditory system prefers, presumably because of evolutionary adaptation, melodically upward over downward steps in sound frequency. The mismatch negativity (MMN) of event-related potentials (ERPs) to auditory oddball stimuli, an index of preattentive auditory change detection, is also augmented for the upward relative to the downward steps. We aimed to test whether this melodic MMN asymmetry shows specificity to the oddball stimuli. Auditory ERPs were recorded in adult humans during a visual task. In an oddball condition, a repeated 400 Hz tone was occasionally (P=0.01) replaced either by a 380 Hz or by a 420 Hz tone. In a same-rate condition, the tones of the three frequencies occurred at equal probabilities (P=0.33). In the oddball condition, frontally augmented ERPs of negative polarity (MMN) were found to be of higher amplitude for the 420 Hz tone than for the 380 Hz tone. In the same-rate condition, ERPs did not distinguish between the tones. The findings associate the melodic MMN asymmetry with the neural detection of oddball tones in particular.     

Infants’ brain responses for speech sound changes in fast multifeature MMN paradigm

ObjectiveWe investigated whether newborn speech-sound discrimination can be studied in 40 min using fast multifeature mismatch negativity (MMN) paradigm and do the results differ from those obtained with the traditional oddball paradigm.MethodsNewborns’ MMN responses to five types of changes (consonant identity, F0, intensity, vowel duration and vowel identity) were recorded in the multifeature group (N = 15) and vowel duration and vowel identity changes in the oddball group (N = 13), after which the MMNs from both groups were compared with each others.ResultsStatistically significant MMNs in the 190–600 ms time range from the stimulus onset were found for most change types in both paradigms. Newborn MMN responses were predominantly positive but a small number of participants elicited negative MMNs instead. MMN amplitudes did not differ between the multifeature and oddball groups.ConclusionsNewborn speech-sound discrimination can be assessed in a short recording time using the fast multifeature paradigm.SignificanceThe paradigm presented here can be used to record extensive auditory discrimination profiles in newborns and assess development of speech-sound discrimination and its difficulties.     

Temporal integration of deviant sound in automatic detection reflected by mismatch negativity

Mismatch negativity (MMN) is an event-related potential that is elicited by deviant sounds that are presented along with frequent sounds in the absence of attention. Auditory MMN is generated by the comparison process between sensory memory trace of a frequent auditory event and a deviant event. It is well known that frequent sounds are encoded in memory trace and processed as a single unit within 160-170 ms. This study examined whether deviant sound would be similarly processed as a temporal unit. Twelve healthy men were presented with relatively short standard sounds and relatively long deviant sounds that contained an omitted (i.e. silent) part. Three types of deviant sounds were designed to vary in duration. The MMN amplitude was gradually enhanced from the short to long duration deviant events that contained an omitted part. In contrast, MMN latency showed no significant differences among the deviants. These findings show that deviant sounds are also processed as a unitary event.     

The use of conditional inference to reduce prediction error—A mismatch negativity (MMN) study

The brain uses regularities in the sound environment to build inference models predicting the most likely attributes of subsequent sounds. When the inference model fails, a prediction-error signal (the mismatch negativity or MMN) is generated. This study is designed to explore the capacity to use information about when a deviant sound will occur to switch between inference models in memory. We measured MMN generated to rare frequency, duration, intensity and spatial deviant sounds randomly occurring in a stream of identical repeating “standard” sounds. We then measured MMN to the same deviants in a linked sequence where deviants were paired—duration deviants followed an intensity change and spatial deviants followed a frequency change. To minimise prediction error, the brain should use the occurrence of the intensity and frequency deviant to prompt a change in the dominant inference (“expect-the-standard”) to anticipate the characteristics of the linked deviant. Anticipation was quantified as the proportion decline in duration and spatial MMN in the linked versus random sequence. We report three main outcomes on a sample of 23 healthy adults: (1) a significant reduction in duration MMN amplitude in linked versus random sequence; (2) a subgroup of participants exhibited significant reduction in spatial MMN amplitude in linked versus random sequence; and (3) the capacity to anticipate a linked deviant (reduce MMN) was a related to performance on the Continuous Performance Task-Identical Pairs. The results are discussed with respect to a possible co-reliance of CPT-IP and inference models on the inferior frontal gyrus.     

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.     

Processing acoustic change and novelty in newborn infants

Research on event-related potential (ERP) correlates of auditory deviance-detection in newborns provided inconsistent results; temporal and topographic ERP characteristics differed widely across studies and individual infants. Robust and reliable ERP responses were, however, obtained to sounds (termed 'novel' sounds), which cover a wide range of frequencies and widely differ from the context provided by a repeating sound [Kushnerenko et al. , (2002) NeuroReport , 13, 1843–1848]. The question we investigated here is whether this effect can be attributed to novelty per se or to acoustic characteristics of the 'novel' sounds, such as their wide frequency spectrum and high signal energy compared with the repeated tones. We also asked how sensitivity to these stimulus aspects changes with development. Twelve newborns and 11 adults were tested in four different oddball conditions, each including a 'standard' sound presented with the probability of 0.8 and two types of infrequent 'deviant' sounds (0.1 probability, each). Deviants were (i) 'novel' sounds (diverse environmental noises); (ii) white-noise segments, or harmonic tones of (iii) a higher pitch, or (iv) higher intensity. In newborns, white-noise deviants elicited the largest response in all latency ranges, whereas in adults, this phenomenon was not found. Thus, newborns appear to be especially sensitive to sounds having a wide frequency spectrum. On the other hand, the pattern of results found for the late discriminative ERP response indicates that newborns may also be able to detect novelty in acoustic stimulation, although with a longer latency than adults, as shown by the ERP response. Results are discussed in terms of developmental refinement of the initially broadly tuned neonate auditory system.     

Organizing sound sequences in the human brain: the interplay of auditory streaming and temporal integration

The present study examined the relationship between two of the early brain processes of sound organization: auditory streaming and the temporal window of integration (TWI). Presented at a fast stimulus delivery rate, two tones alternating in frequency are perceived as separate streams of high and low sounds. However, when two sounds are presented within a ca. 200 ms temporal window, they are often processed as a single auditory event. Both stream segregation and temporal integration occur even in the absence of focused attention as was shown by their effect on the mismatch negativity (MMN) event-related potential. The goal of the present study was to determine the precedence between these two sound organization processes by using the stimulus-omission MMN paradigm. Infrequently omitting one stimulus from a homogeneous tone sequence only elicits an MMN when the stimulus onset asynchrony separating successive tones is shorter than 170 ms. This demonstrates the effect of the TWI. Magnetic brain responses elicited by infrequent stimulus omissions appearing in a sequence of two alternating tones were recorded. The magnetic MMN was elicited by tone omission when the alternating tones formed a single stream (with no or only small frequency separation between the two tones) but not when separate high and low streams emerged in perception (large frequency separation between the two alternating tones). This result shows that auditory streaming takes precedence over the processes of temporal integration.     

The discrimination of and orienting to speech and non-speech sounds in children with autism

The present study aimed to find out how different stages of cortical auditory processing (sound encoding, discrimination, and orienting) are affected in children with autism. To this end, auditory event-related potentials (ERP) were studied in 15 children with autism and their controls. Their responses were recorded for pitch, duration, and vowel changes in speech stimuli, and for corresponding changes in the non-speech counterparts of the stimuli, while the children watched silent videos and ignored the stimuli. The responses to sound repetition were diminished in amplitude in the children with autism, reflecting impaired sound encoding. The mismatch negativity (MMN), an ERP indexing sound discrimination, was enhanced in the children with autism as far as pitch changes were concerned. This is consistent with earlier studies reporting auditory hypersensitivity and good pitch-processing abilities, as well as with theories proposing enhanced perception of local stimulus features in individuals with autism. The discrimination of duration changes was impaired in these children, however. Finally, involuntary orienting to sound changes, as reflected by the P3a ERP, was more impaired for speech than non-speech sounds in the children with autism, suggesting deficits particularly in social orienting. This has been proposed to be one of the earliest symptoms to emerge, with pervasive effects on later development.     

Delayed mismatch field for speech and non-speech sounds in children with autism

This study investigated the magnetic mismatch field elicited by changes in streams of vowels or spectrally matched tones in children with autism spectrum disorder (ASD) relative to children with typical development to explore whether impaired sound discrimination may contribute to language impairments in autism spectrum disorder. Using magnetoencephalography, we recorded evoked neural activity to 300-Hz and 700-Hz tones (and /u/ and /a/ vowels) presented in an oddball paradigm with deviant stimuli (15%) occurring within a train of standards (85%). The magnetic mismatch field was robustly observed in both groups, but children with autism spectrum disorder demonstrated a significantly delayed magnetic mismatch field compared with typically developing peers. Difficulty parsing transient differences in sounds may lead to impaired acoustic or phonological representations and subsequent language impairment in autism spectrum disorder.     

The mismatch negativity to frequency deviant stimuli during natural sleep

Eight subjects spent a single night in the sleep laboratory. Event-related potentials (ERPs) were recorded during the presentation of two auditory ‘oddball’ stimulus conditions in which tonal frequency was manipulated. In the first condition, 1000 Hz ‘standard’ and 2000 Hz ‘deviant’ tones were presented. In the second condition, the deviant tone was reduced to 1050 Hz. In both conditions, deviant probability was 0.2. Stimuli were presented every 600 ms during wakefulness and stages 2, 4, and REM of sleep. A distinctive N1 wave was visible in both stimulus conditions when the subject was awake. The deviant stimuli elicited a ‘mismatch negativity’ (MMN) that inverted in polarity at the mastoid. In REM sleep, an N1 and a MMN were also elicited in both conditions. In the large deviance condition, the MMN had a slightly attenuated amplitude and was shorter in duration while in the small deviant condition, its peak latency was unusually early. Neither the N1 nor the MMN could be recorded in non-REM sleep.