Automatic integration of auditory and visual information is not simultaneous in Chinese

ERP studies have revealed that for alphabetic languages letter/speech-sound integration develops with brain maturation and reading instruction over a relatively long period of time. Experienced adult readers associate letters and speech sounds automatically, as indexed by enhanced mismatch negativity (MMN) to simultaneously presented stimuli, but reveal attenuated MMN when the speech sound stimuli are presented with a delay. Chinese as a logographic language differs substantially from alphabetic languages and therefore integration processes might be characterized by unique timing mechanisms. In the present study, MMN was used to investigate the timing and automaticity of association between characters and lexical tones in adult native Chinese speakers. A character was presented simultaneously with a lexical tone, or with either a 100 ms stimulus onset asynchrony (SOA) or a 200 ms SOA in separate conditions. MMN was enhanced when the character and the lexical tone were presented with 100 ms SOA, while no significant MMN enhancement was observed with simultaneous presentation or with 200 ms SOA. These results suggest that the automatic association of characters and lexical tones in experienced Chinese adult readers requires more processing time than for alphabetic languages. These results highlight critical differences between fundamental reading processes across different writing systems. The neural differences between alphabetic and logographic languages for letter/character and speech-sound/tone integration need to be taken into consideration when considering past and future research on reading processes in these languages and especially for investigations of reading disorders, such as developmental dyslexia.     

Segmental and suprasegmental features in speech perception in Cantonese‐speaking second graders: An ERP study

Using a multiple‐deviant oddball paradigm, this study examined second graders' brain responses to Cantonese speech. We aimed to address the question of whether a change in a consonant or lexical tone could be automatically detected by children. We measured auditory mismatch responses to place of articulation and voice onset time (VOT), reflecting segmental perception, as well as Cantonese lexical tones including level tone and contour tone, reflecting suprasegmental perception. The data showed that robust mismatch negativities (MMNs) were elicited by all deviants in the time window of 300–500 ms in second graders. Moreover, relative to the standard stimuli, the VOT deviant elicited a robust positive mismatch response, and the level tone deviant elicited a significant MMN in the time window of 150–300 ms. The findings suggest that Hong Kong second graders were sensitive to neural discriminations of speech sounds both at the segmental and suprasegmental levels.     

Emotionally negative pictures increase attention to a subsequent auditory stimulus

Emotionally negative stimuli serve as a mechanism of biological preparedness to enhance attention. We hypothesized that emotionally negative stimuli would also serve as motivational priming to increase attention resources for subsequent stimuli. To that end, we tested 11 participants in a dual sensory modality task, wherein emotionally negative pictures were contrasted with emotionally neutral pictures and each picture was followed 600 ms later by a tone in an auditory oddball paradigm. Each trial began with a picture displayed for 200 ms; half of the trials began with an emotionally negative picture and half of the trials began with an emotionally neutral picture; 600 ms following picture presentation, the participants heard either an oddball tone or a standard tone. At the end of each trial (picture followed by tone), the participants categorized, with a button press, the picture and tone combination. As expected, and consistent with previous studies, we found an enhanced visual late positive potential (latency range = 300-700 ms) to the negative picture stimuli. We further found that compared to neutral pictures, negative pictures resulted in early attention and orienting effects to subsequent tones (measured through an enhanced N1 and N2) and sustained attention effects only to the subsequent oddball tones (measured through late processing negativity, latency range = 400-700 ms). Number pad responses to both the picture and tone category showed the shortest response latencies and greatest percentage of correct picture-tone categorization on the negative picture followed by oddball tone trials. Consistent with previous work on natural selective attention, our results support the idea that emotional stimuli can alter attention resource allocation. This finding has broad implications for human attention and performance as it specifically shows the conditions in which an emotionally negative stimulus can result in extended stimulus evaluation.     

Effects of inter-stimulus interval (ISI) duration on the N1 and P2 components of the auditory event-related potential

The N1 and P2 components of the event-related potential are relevant markers in the processing of auditory information, indicating the presence of several acoustic phenomena, such as pure tones or speech sounds. In addition, the expression of these components seems to be sensitive to diverse experimental variations. The main purpose of the present investigation was to explore the role of inter-stimulus interval (ISI) on the N1 and P2 responses, considering two widely used experimental paradigms: a single tone task (1000 Hz sound repeated in a fixed rhythm) and an auditory oddball (80% of the stimuli were equal to the sound used in the single tone and the remaining were a 1500 Hz tone). Both tasks had four different conditions, and each one tested a fixed value of ISI (600, 1000, 3000, or 6000 ms). A sample of 22 participants performed these tasks, while an EEG was recorded, in order to examine the maximum amplitude of the N1 and P2 components. Analysis of the stimuli in the single tone task and the frequent tones in the oddball task revealed a similar outcome for both tasks and for both components: N1 and P2 amplitudes were enhanced in conditions with longer ISIs regardless of task. This response pattern emphasizes the dependence of both the N1 and P2 components on the ISI, especially in a scenario of repetitive and regular stimulation. The absence of task effects suggests that the ISI effect reported may depend on refractory mechanisms rather than being due to habituation effects.     

Association of a Rare Variant with Mismatch Negativity in a Region Between <Emphasis Type="Italic">KIAA0319</Emphasis> and <Emphasis Type="Italic">DCDC2</Emphasis> in Dyslexia

It has been repeatedly shown that mismatch negativity (MMN), an event related potential measurement, reveals differences between dyslexic children and age-matched controls. MMN reflects the automatic detection of deviance between a stream of incoming sounds presented to the passive listener, and deficits in MMN (i.e. attenuated amplitudes) have been especially reported in dyslexia for detecting differences between speech sounds (e.g./ba/vs./da/). We performed an association analysis in 200 dyslexic children. This analysis focused on two MMN components, an early MMN (188–300 ms) and a late MMN (300–710 ms), and the dyslexia candidate genes KIAA0319 and DCDC2 on chromosome 6. Additionally, we imputed rare variants located in this region based on the 1000 genomes project. We identified four rare variants that were significantly associated with the late MMN component. For three of these variants, which were in high LD to each other, genotyping confirmed the association signal. Our results point to an association between late MMN and rare variants in a candidate gene region for dyslexia.     

Ultrafast tracking of sound location changes as revealed by human auditory evoked potentials

The rapid discrimination of auditory location information enables grouping and selectively attending to specific sound sources. The typical indicator of auditory change detection is the mismatch negativity (MMN) occurring at a latency of about 100-250 ms. However, recent studies have revealed the existence of earlier markers of frequency deviance detection in the middle-latency response (MLR). Here, we measured the MLR and MMN to changes in sound location. Clicks were presented in either the left or right hemifields during oddball (rare 30°-shifts in location), reversed oddball, and control (sounds occurring equiprobably from five locations) conditions. Clicks at deviant locations elicited an MMN and an enhanced Na component of the MLR peaking at 20 ms compared to clicks at standard or control locations. Whereas MMN was not significantly lateralized, the Na effect showed a contralateral dominance. These findings indicate that, also for sound location changes, early detection processes exist upstream of MMN.     

Event-related potentials in auditory backward recognition masking: A new way to study the neurophysiological basis of sensory memory in humans

Task-irrelevant pairs of short tones were presented to healthy human subjects while electric potentials were recorded from their scalp (‘event-related brain potential’, ERP). Infrequent increments in the frequency of the first tone of the repetitive tone-pair elicited an extra ERP component termed ‘mismatch negativity’ (MMN) when the silent interval between the first and second tone of the pair (‘inter-tone interval’) was long (150, 300, or 400 ms) but not when this interval was short (20 or 50 ms). This effect did not depend on whether the two tones of the tone-pair were presented to the same or to different ears. The present inter-tone interval effect is consistent with the effects of backward-masking on recognition performance in audition, suggesting that the MMN reflects the neurophysiological basis of echoic memory.     

Auditory event-related potentials and alpha oscillations in the psychosis prodrome: Neuronal generator patterns during a novelty oddball task

Prior research suggests that event-related potentials (ERP) obtained during active and passive auditory paradigms, which have demonstrated abnormal neurocognitive function in schizophrenia, may provide helpful tools in predicting transition to psychosis. In addition to ERP measures, reduced modulations of EEG alpha, reflecting top-down control required to inhibit irrelevant information, have revealed attentional deficits in schizophrenia and its prodromal stage. Employing a three-stimulus novelty oddball task, nose-referenced 48-channel ERPs were recorded from 22 clinical high-risk (CHR) patients and 20 healthy controls detecting target tones (12% probability, 500 Hz; button press) among nontargets (76%, 350 Hz) and novel sounds (12%). After current source density (CSD) transformation of EEG epochs (− 200 to 1000 ms), event-related spectral perturbations were obtained for each site up to 30 Hz and 800 ms after stimulus onset, and simplified by unrestricted time–frequency (TF) principal components analysis (PCA). Alpha event-related desynchronization (ERD) as measured by TF factor 610–9 (spectral peak latency at 610 ms and 9 Hz; 31.9% variance) was prominent over right posterior regions for targets, and markedly reduced in CHR patients compared to controls, particularly in three patients who later developed psychosis. In contrast, low-frequency event-related synchronization (ERS) distinctly linked to novels (260–1; 16.0%; mid-frontal) and N1 sink across conditions (130–1; 3.4%; centro-temporoparietal) did not differ between groups. Analogous time-domain CSD-ERP measures (temporal PCA), consisting of N1 sink, novelty mismatch negativity (MMN), novelty vertex source, novelty P3, P3b, and frontal response negativity, were robust and closely comparable between groups. Novelty MMN at FCz was, however, absent in the three converters. In agreement with prior findings, alpha ERD and MMN may hold particular promise for predicting transition to psychosis among CHR patients.     

First‐impression bias effects on mismatch negativity to auditory spatial deviants

Internal models of regularities in the world serve to facilitate perception as redundant input can be predicted and neural resources conserved for that which is new or unexpected. In the auditory system, this is reflected in an evoked potential component known as mismatch negativity (MMN). MMN is elicited by the violation of an established regularity to signal the inaccuracy of the current model and direct resources to the unexpected event. Prevailing accounts suggest that MMN amplitude will increase with stability in regularity; however, observations of first‐impression bias contradict stability effects. If tones rotate probabilities as a rare deviant (p = .125) and common standard (p = .875), MMN elicited to the initial deviant tone reaches maximal amplitude faster than MMN to the first standard when later encountered as deviant—a differential pattern that persists throughout rotations. Sensory inference is therefore biased by longer‐term contextual information beyond local probability statistics. Using the same multicontext sequence structure, we examined whether this bias generalizes to MMN elicited by spatial sound cues using monaural sounds (n = 19, right first deviant and n = 22, left first deviant) and binaural sounds (n = 19, right first deviant). The characteristic differential modulation of MMN to the two tones was observed in two of three groups, providing partial support for the generalization of first‐impression bias to spatially deviant sounds. We discuss possible explanations for its absence when the initial deviant was delivered monaurally to the right ear.     

Auditory sensory memory and the aging brain: A mismatch negativity study

The mismatch negativity (MMN) component of the auditory event-related potential has been used in the past to study between group differences in the accuracy and retention of information in auditory sensory memory (ASM). The MMN is elicited by infrequent 'deviant' tones that differ from a repeating 'standard' tone. In the present study, the type of deviant and the time interval between tones (stimulus-onset asynchrony: SOA) were manipulated in a study of normal aging. MMN responses of an elderly (mean age = 69) and a young group (mean age = 21) to both a duration and a frequency deviant tone were measured at a short (450 ms) and long (3 s) SOA. A smaller and later MMN (recorded at Fz) was observed in the elderly relative to the young group across SOA and Deviant conditions. The results are consistent with an age-related deficit in the encoding of sound properties in ASM. However, analysis of the MMN reversal at the mastoids provides some support for the proposal that the elderly have an additional deficit related to the retention of information in ASM.     

Cortico-cortical phase synchrony in auditory mismatch processing

Previous studies have shown a reduced MMN in patients with lesions in the temporal or frontal lobes, suggesting a temporal-frontal involvement in change detection. However, how the temporal lobe interacts with other brain areas in responding to unexpected deviant stimuli remains unclear. This study aimed to evaluate the functional connectivity between cerebral regions by measuring the phase synchrony of magnetoencephalographic (MEG) signals elicited by regular simple tones and their duration-deviants in an oddball paradigm. We measured MEG responses to deviant (1000-Hz frequency, 50-ms duration, probability of 15%) and standard (1000-Hz frequency, 100-ms duration) sounds in 10 healthy adults. By using the Morlet wavelet-based analysis, relative phase synchronization values of 4-40 Hz MEG responses at 150-300 ms after stimulus onset were calculated with respect to a reference channel from the temporal region. Phase synchronization was clearly identified between the temporal and ipsilateral frontal region in the auditory evoked responses. This temporal-frontal synchronization was significantly larger in deviants-elicited than standards-elicited activation at 4-25 Hz in the left hemisphere (p < 0.05), and at 4-8 Hz in the right hemisphere (p < 0.01). Also, temporal-temporal and temporal-parietal phase synchronies were found in deviants-evoked 4-8 Hz responses.The present results suggest an involvement of temporal-temporal, temporal-frontal, and temporal-parietal neuronal network in detecting auditory change. Phase synchronization analysis may provide a useful window to further understanding of the cerebral reactivity during the processing of auditory deviants.     

Detecting violations of temporal regularities in waking and sleeping two-month-old infants

Correctly processing rapid sequences of sounds is essential for developmental milestones, such as language acquisition. We investigated the sensitivity of two-month-old infants to violations of a temporal regularity, by recording event-related brain potentials (ERPs) in an auditory oddball paradigm from 36 waking and 40 sleeping infants. Standard tones were presented at a regular 300 ms inter-stimulus interval (ISI). One deviant, otherwise identical to the standard, was preceded by a 100 ms ISI. Two other deviants, presented with the standard ISI, differed from the standard in their spectral makeup. We found significant differences between ERP responses elicited by the standard and each of the deviant sounds. The results suggest that the ability to extract both temporal and spectral regularities from a sound sequence is already functional within the first few months of life. The scalp distribution of all three deviant-stimulus responses was influenced by the infants’ state of alertness.     

Stimulatory effect of harmane and other beta-carbolines on locus coeruleus neurons in anaesthetized rats

The present study investigated the effects of decreased audibility of the speech sounds 'ba' and 'da' on the mismatch negativity (MMN). Audibility was altered by varying the intensity of the masking noise to be either 0 (no noise), 65, 70 or 75 dB speech perception level. Cortical event-related potentials were recorded while normal listeners (n=7) were instructed to ignore the stimuli. In a separate condition, subjects were asked to signal detection of the deviant stimulus by button-press. As audibility of speech sounds was decreased, MMN peak amplitude decreased and MMN peak latency increased. Behavioral responses were in accordance with the MMN data. Hit rates decreased as audibility decreased. These results suggest that both pre-attentive and attentive speech discrimination deteriorate following a reduction in audibility.     

The effect of perceptual grouping on the mismatch negativity

The mismatch negativity (MMN) was used as a probe to evaluate changes, with age, of transient auditory memory. Subjects were 16 young (M = 23 years) and 16 old (M = 72 years) people. Standard auditory stimuli were presented in trains of eight tones (1000 Hz) with either a I-s or 8-s intertrain interval (ITI). Occasionally, the first stimulus of a train was replaced with a 1200 Hz tone (deviant). The MMN was recorded while subjects watched a silent movie and ignored the sounds. Both groups of subjects showed an MMN response to deviant stimuli under the 1-s ITI condition, but MMNs were only seen for some subjects under the 8-s ITI condition. After MMN recording, subjects performed a discrimination task to the tones used for recording MMNs. Accuracy for both groups was near 100% at both ITIs. These results suggest that generation of MMN is a function of the perceptual grouping of the acoustical stimuli and that the integrity of perceptual grouping may be maintained with increased age.     

Electrophysiological evidence of temporal preparation driven by rhythms in audition

Reaction speed to respond to an auditory target stimulus is enhanced when it is presented at a moment matching the temporal structure of a preceding regular rhythm (Sanabria et al., 2011). However, the electrophysiological correlates of this behavioural enhancement remain unknown. In the present study, participants’ performed a simple auditory reaction time task in which a regular rhythm with either a fast (400 ms interval between the tones making the rhythm) or a slow (900 ms interval between the tones making the rhythm) was presented prior to the target. The target tone could be presented, with the same probability, 400 ms or 900 ms after the offset of the rhythmic sequence. The behavioural results showed that the fastest responses were obtained when the target appeared in synchrony with the preceding rhythm (e.g., the target was presented 900 ms after the slow rhythm). This behavioural benefit was accompanied by amplitude modulations of the N1 potential and the P2 potential, both related to the processing of the auditory target. Crucially, these electrophysiological modulations were obtained in both the fast and the slow rhythm conditions. The current research demonstrates that rhythms with different paces can drive temporal preparation exogenously, affecting early and late stages of auditory neural processing.     

Deviance detection in congruent audiovisual speech: Evidence for implicit integrated audiovisual memory representations

Detection of deviant speech syllables embedded in continuous noise was investigated in an oddball paradigm. Behavioral results showed improvement of detecting and identifying the syllables when congruent visual speech accompanied the utterances. A centrally maximal negative ERP difference wave peaking at approximately 290 ms post-stimulus was elicited by audiovisual but not by auditory- or visual-only task-irrelevant deviant syllables. Whereas the circumstances of the elicitation of this ERP response are similar to those of the mismatch negativity component (MMN and its visual counterpart, vMMN), its scalp distribution differs from that of both unimodal MMNs. Elicitation of an MMN-like ERP response (termed here as the audiovisual MMN: avMMN) suggests that detection of the audiovisual deviants involved integrated audiovisual memory representations. The pattern of behavioral and ERP results suggest that the formation of such cross-modal memory representation does not require voluntary operations and may even proceed for stimuli outside the focus of attention.     

Cascade and no‐repetition rules are comparable controls for the auditory frequency mismatch negativity in oddball tasks

The mismatch negativity (MMN) has been widely studied with oddball tasks to index processing of unexpected auditory change. The MMN is computed as the difference of deviant minus standard and is used to capture the pattern violation by the deviant. However, this oddball MMN is confounded because the deviant differs physically from the standard and is presented less often. To improve measurement, the same tone as the deviant is presented in a separate condition. This control tone is equiprobable with other tones and is used to compute a corrected MMN (deviant minus control). Typically, the tones are in random order except that consecutive tones are not identical (no‐repetition rule). In contrast, a recent study on frequency MMN presented tones in a regular up‐and‐down sequence (cascade rule). If the cascade rule is detected more easily than the no‐repetition rule, there should be a lower risk of a confounding MMN within the cascade condition. However, in previous research, the cascade and no‐repetition conditions differed not only in the regularity of the tone sequence but also in number of tones, frequency range, and proportion of tones. We controlled for these differences to isolate effects of regularity in the tone sequence. Results of our preregistered analyses provided moderate evidence (BF₀₁>6) that the corrected MMN did not differ between cascade and no‐repetition conditions. These findings imply that no‐repetition and cascade rules are processed similarly and that the no‐repetition condition provides an adequate control in frequency MMN.     

Effect of deviance direction and calculation method on duration and frequency mismatch negativity (MMN)

The mismatch negativity (MMN) component of the auditory event-related potential (ERP) reflects the process of change detection in the auditory system. The present study investigated the effect of deviance direction (increment vs. decrement) and calculation method (traditional vs. same-stimulus) on the amplitude of MMN. MMN was recorded for increments and decrements in frequency and duration in 20 adults. The stimuli (standard/deviant) were 250 Hz/350 Hz (frequency MMN) and 200 ms/300 ms (duration MMN) for increment MMN and vice versa for decrement MMN. Amplitude of MMN was calculated in two ways: the traditional method (subtracting ERP to the standard from the deviant presented in the same block) and the same-stimulus method (subtracting ERP to identical stimuli presented as standard in one block and deviant in another block). We found that increments in frequency produced higher MMN amplitudes compared to decrements for both methods of calculation. For duration deviance, the decrement MMN was absent in the traditional method, while the decrement and increment MMN did not differ for the same-stimulus method. These findings suggest that the brain processes frequency increments and decrements in different ways. The results also suggest the use of same-stimulus method for the calculation of duration MMN when long duration stimuli are used.     

Mismatch negativity for item rather than serial-order information in a 150-ms tone series that is not repeated as a melodic pattern

Speech, for example, consists of fast-paced (>5/s) sounds in specific spectrotemporal patterns. Humans are generally held to be able to represent not only such sounds themselves (item information) but also their serial order (order-information) as a repeated melody with ease, as suggested by studies on the mismatch negativity (MMN) of event-related potentials (ERPs). The present study tested whether this ability tolerates the absence of the support of melodic repetitiveness. ERPs were recorded from adult humans presented with rare 150-ms series of three 50-ms tones ('deviants') interspersed with frequently repeated ones ('standards'). The frequency of each tone was pseudorandomly one of four alternative frequencies. The series were of type 'AAB' (two tones of one frequency followed by a tone of another frequency), 'ABB' (two tones of one frequency preceded by a tone of another frequency), or 'AAA' (three tones of one frequency). The MMN was robustly elicited by AAA deviants against AAB standards. It was, however, less distinct for ABB deviants against AAB standards and even statistically non-significant for AAB deviants against ABB standards. MMN generation in the human brain thus seems to be based on item rather than serial-order information in a rapid spectro-temporal pattern of acoustic signals that is not repeated frequently in the short term.     

Stimulus complexity enhances auditory discrimination in patients with extremely severe brain injuries

There is controversy as to what extent the processing of spectrally rich sounds in the human auditory cortex is related to the processing of singular frequencies. An informative index of the function of the auditory cortex, particularly important in neurological patients, is the mismatch negativity (MMN), a component of auditory event-related potentials. In the present study the MMN was recorded in 79 patients with extremely severe diffuse brain injuries, most of them in persistent vegetative state or minimal consciousness state. Both sinusoidal ('pure') and complex musical tones were used. Different statistical approaches converged in that musical tones elicited an MMN significantly more frequently, and of a larger amplitude, than simple sine tones. This implies that using simple stimuli in clinical populations may lead to a severe underestimation of the functional state of a patient's auditory system. The findings are also in line with behavioral and physiological data indicating independent processing of complex sounds in the auditory cortex.