Mismatch Negativity Research Articles

Intensity dependence of auditory evoked potentials distinguish participants with unmedicated depression from non-depressed controls.

Depression is a heterogeneous syndrome that impacts an individual's emotional, social, cognitive and bodily functioning. Depression is associated with biases in emotional processing, but alterations in basic sensory processing have received less attention in depression research. Here, we measured event-related potentials (ERPs) in response to changes in the intensity of auditory stimuli and the location of somatosensory stimuli in participants with depression and in non-depressed control participants. We tested whether auditory mismatch negativity, P3a or N1 intensity dependence response or somatosensory mismatch response, P3a, P50 or N80 can dissociate depressed participants and non-depressed controls, and we also analysed the effects of depression medication and age in this sample. N1 intensity dependence response was increased in unmedicated depressed participants relative to non-depressed controls. When age was controlled for in the analysis, the effect of depression was only at a trend level. N1 intensity dependence response correlated with depression severity at the whole sample level. We did not observe any depression-related alterations in auditory mismatch negativity or P3a or somatosensory ERPs. Our results may reflect an association between the N1 intensity dependence response and altered neurotransmitter activity in depression, but this should be confirmed in future studies.

Leveraging mixed-effects location scale models to assess the ERP mismatch negativity’s psychometric properties and trial-by-trial neural variability in toddler-mother dyads

Trial-by-trial neural variability, a measure of neural response stability, has been examined in relation to behavioral indicators using summary measures, but these methods do not characterize meaningful processes underlying variability. Mixed-effects location scale models (MELSMs) overcome these limitations by accounting for predictors and covariates of variability but have been rarely used in developmental studies. Here, we applied MELSMs to the ERP auditory mismatch negativity (MMN), a neural measure often related to language and psychopathology. 84 toddlers and 76 mothers completed a speech-syllable MMN paradigm. We extracted early and late MMN mean amplitudes from trial-level waveforms. We first characterized our sample’s psychometric properties using MELSMs and found a wide range of subject-level internal consistency. Next, we examined the relation between toddler MMNs with theoretically relevant child behavioral and maternal variables. MELSMs offered better model fit than analyses that assumed constant variability. We found significant individual differences in trial-by-trial variability but no significant associations between toddler variability and their language, irritability, or mother variability indices. Overall, we illustrate how MELSMs can characterize psychometric properties and answer questions about individual differences in variability. We provide recommendations and resources as well as example code for analyzing trial-by-trial neural variability in future studies.

Adaptation patterns and their associations with mismatch negativity: An electroencephalogram (EEG) study with controlled expectations.

Adaptation refers to the decreased neural response that occurs after repeated exposure to a stimulus. While many electroencephalogram (EEG) studies have investigated adaptation by using either single or multiple repetitions, the adaptation patterns under controlled expectations manifested in the two main auditory components, N1 and P2, are still largely unknown. Additionally, although multiple repetitions are commonly used in mismatch negativity (MMN) experiments, it is unclear how adaptation at different time windows contributes to this phenomenon. In this study, we conducted an EEG experiment with 37 healthy adults using a random stimulus arrangement and extended tone sequences to control expectations. We tracked the amplitudes of the N1 and P2 components across the first 10 tones to examine adaptation patterns. Our findings revealed an L-shaped adaptation pattern characterised by a significant decrease in N1 amplitude after the first repetition (N1 initial adaptation), followed by a continuous, linear increase in P2 amplitude after the first repetition (P2 subsequent adaptation), possibly indicating model adjustment. Regression analysis demonstrated that the peak amplitudes of both the N1 initial adaptation and the P2 subsequent adaptation significantly accounted for variance in MMN amplitude. These results suggest distinct adaptation patterns for multiple repetitions across different components and indicate that the MMN reflects a combination of two processes: the initial adaptation in the N1 and a continuous model adjustment effect in the P2. Understanding these processes separately could have implications for models of cognitive processing and clinical disorders.

A Dual Role for the Dorsolateral Prefrontal Cortex (DLPFC) in Auditory Deviance Detection.

In the oddball paradigm, the dorsolateral prefrontal cortex (DLPFC) is often associated with active cognitive responses, such as maintaining information in working memory or adapting response strategies. While some evidence points to the DLPFC's role in passive auditory deviance perception, a detailed understanding of the spatiotemporal neurodynamics involved remains unclear. In this study, event-related optical signals (EROS) and event-related potentials (ERPs) were simultaneously recorded for the first time over the prefrontal cortex using a 64-channel electroencephalography (EEG) system, during passive auditory deviance perception in 12 right-handed young adults (7 women and 5 men). In this oddball paradigm, deviant stimuli (a 1500 Hz pure tone) elicited a negative shift in the N1 ERP component, related to mismatch negativity (MMN), and a significant positive deflection associated with the P300, compared to standard stimuli (a 1000 Hz tone). We hypothesize that the DLPFC not only participates in active tasks but also plays a critical role in processing deviant stimuli in passive conditions, shifting from pre-attentive to attentive processing. We detected enhanced neural activity in the left middle frontal gyrus (MFG), at the same timing of the MMN component, followed by later activation at the timing of the P3a ERP component in the right MFG. Understanding these dynamics will provide deeper insights into the DLPFC's role in evaluating the novelty or unexpectedness of the deviant stimulus, updating its cognitive value, and adjusting future predictions accordingly. However, the small number of subjects could limit the generalizability of the observations, in particular with respect to the effect of handedness, and additional studies with larger and more diverse samples are necessary to validate our conclusions.

Neural Signature and Decoding of Unmanned Aerial Vehicle Operators in Emergency Scenarios Using Electroencephalography.

Brain-computer interface (BCI) offers a novel means of communication and control for individuals with disabilities and can also enhance the interactions between humans and machines for the broader population. This paper explores the brain neural signatures of unmanned aerial vehicle (UAV) operators in emergencies and develops an operator's electroencephalography (EEG) signals-based detection method for UAV emergencies. We found regularity characteristics similar to classic event-related potential (ERP) components like visual mismatch negativity (vMMN) and contingent negative variation (CNV). Source analysis revealed a sequential activation of the occipital, temporal, and frontal lobes following the onset of emergencies, corresponding to the processing of attention, emotion, and motor intention triggered by visual stimuli. Furthermore, an online detection system was implemented and tested. Experimental results showed that the system achieved an average accuracy of over 88% in detecting emergencies with a detection latency of 431.95 ms from the emergency onset. This work lays a foundation for understanding the brain activities of operators in emergencies and developing an EEG-based detection method for emergencies to assist UAV operations.

Language experience shapes predictive coding of rhythmic sound sequences.

Perceptual systems heavily rely on prior knowledge and predictions to make sense of the environment. Predictions can originate from multiple sources of information, including contextual short-term priors, based on isolated temporal situations, and context-independent long-term priors, arising from extended exposure to statistical regularities. While the effects of short-term predictions on auditory perception have been well-documented, how long-term predictions shape early auditory processing is poorly understood. To address this, we recorded magnetoencephalography data from native speakers of two languages with different word orders (Spanish: functor-initial vs Basque: functor-final) listening to simple sequences of binary sounds alternating in duration with occasional omissions. We hypothesized that, together with contextual transition probabilities, the auditory system uses the characteristic prosodic cues (duration) associated with the native language's word order as an internal model to generate long-term predictions about incoming non-linguistic sounds. Consistent with our hypothesis, we found that the amplitude of the mismatch negativity elicited by sound omissions varied orthogonally depending on the speaker's linguistic background and was most pronounced in the left auditory cortex. Importantly, listening to binary sounds alternating in pitch instead of duration did not yield group differences, confirming that the above results were driven by the hypothesized long-term 'duration' prior. These findings show that experience with a given language can shape a fundamental aspect of human perception - the neural processing of rhythmic sounds - and provides direct evidence for a long-term predictive coding system in the auditory cortex that uses auditory schemes learned over a lifetime to process incoming sound sequences.

Abnormal inter-hemispheric effective connectivity from left to right auditory regions during Mismatch Negativity (MMN) tasks in psychosis

Anomalous Mismatch Negativity (MMN) in psychosis could be a consequence of disturbed neural oscillatory activity at sensory/perceptual stages of stimulus processing. This study investigated effective connectivity within and between the auditory regions during auditory odd-ball deviance tasks. The analyses were performed on two magnetoencephalography (MEG) datasets: one on duration MMN in a cohort with various diagnoses within the psychosis spectrum and neurotypical controls, and one on duration and pitch MMN in first-episode psychosis patients and matched neurotypical controls. We applied spectral Granger causality to MEG source-reconstructed signals to compute effective connectivity within and between the left and right auditory regions. Both experiments showed that duration-deviance detection was associated with early increases of effective connectivity in the beta band followed by increases in the alpha and theta bands, with the connectivity strength linked to the laterality of the MMN amplitude. Compared to controls, people with psychosis had overall smaller effective connectivity, particularly from left to right auditory regions, in the pathway where bilateral information converges toward lateralized processing, often rightward. Blunted MMN in psychosis might reflect a deficit in inter-hemispheric communication between auditory regions, highlighting a “dysconnection” already at preattentive stages of stimulus processing as a model system of widespread pathophysiology.

Exploring mismatch negativity in children with congenital Microtia-Atresia: A Preliminary study

BackgroundTo investigate the characteristics of mismatch negativity (MMN) in terms of latency and amplitude in children with bilateral congenital microtia using a Bone conduction implant (Bonebridge), and to explore the relationship between cortical level auditory discrimination, speech perception, and psychosocial well-being. MethodsThis descriptive, observational, cross-sectional study compared three groups: eight children with bilateral congenital microtia and Bonebridge implants (bilateral group), eight children with unilateral congenital microtia and no hearing aids (unilateral group), and eight children with normal hearing (NH group). Participants underwent MMN evaluation using a classic oddball paradigm with a pure tone burst stimulus, featuring a 1000 Hz standard stimulus and a 1200 Hz deviant stimulus, presented in a sound field at 65 dBHL. Additionally, speech perception tests, the Meaningful Use of Speech Scale (MUSS), and psychosocial status questionnaires, including the Social Anxiety Scale for Children (SASC) and the Children’s Loneliness Scale (CLS), were administered to all subjects. ResultsThe bilateral group’s average MMN latency was 241.23 ± 29.47 ms, and the unilateral group’s was 209.96 ± 54.32 ms, both significantly longer than the NH group’s 146.05 ± 15.73 ms (p < 0.0001, F=3.509, 95 % CI 68.09 to 122.3 and p = 0.0097, F=11.92, 95 % CI 18.07 to 109.8, respectively). However, no significant difference was found in MMN latency between the bilateral and unilateral groups (p = 0.202, F=3.397, 95 % CI −18.84 to 81.36). The unilateral group scored significantly higher on the MUSS (38.63 ± 1.41 vs. 30.75 ± 3.80, p = 0.0001, F=7.276, 95 % CI −11.16 to −4.590), had lower CLS scores (47.13 ± 8.13 vs. 58.25 ± 8.39, p = 0.024, F=1.065, 95 % CI 1.652 to 20.60), and lower SASC scores (4.13 ± 2.09 vs. 6.50 ± 2.25, p = 0.062, F=1.204, 95 % CI −0.138 to 4.89) compared to the bilateral group. MMN latency in the bilateral group correlated with SASC scores. ConclusionThe MMN latency in congenital microtia patients may serve as an indicator of central auditory discrimination capabilities. In children with bilateral congenital microtia and Bonebridge implants, MMN latency can reflect social anxiety conditions to a certain degree.

Visual mismatch negativity in Parkinson’s psychosis and potential for testing treatment mechanisms

Abstract Psychosis and visual hallucinations are a prevalent non-motor symptom of Parkinson’s disease, negatively affecting patients’ quality of life and constituting a greater risk for dementia. Understanding neural mechanisms associated to these symptoms is instrumental for treatment development. The mismatch negativity is an event-related potential evoked by a violation in a sequence of sensory events. It is widely considered an index of sensory change-detection. Reduced mismatch negativity response is one of the most replicated results in schizophrenia and has been suggested to be a superior psychosis marker. To understand whether this event-related potential component could be a similarly robust marker for Parkinson’s psychosis, we used electroencephalography with a change-detection task to study the mismatch negativity in the visual modality in 20 patients with Parkinson’s and visual hallucinations and 18 matched Parkinson’s without hallucinations. We find that visual mismatch negativity is clearly present in patients with PD without hallucinations at both parieto-occipital and frontal sites, whereas patients with Parkinson’s and visual hallucinations show reduced or no differences in the two waveforms, confirming the sensitivity of mismatch negativity to psychosis, even within the same diagnostic group. We also explored the relationship between hallucination severity and visual mismatch negativity amplitude, finding a negative correlation between visual hallucinations severity scores and visual mismatch negativity amplitude at a central frontal (FZ) and parieto-occipital (POZ) electrodes, whereby the more severe or complex (illusions, formed visual hallucinations) the symptoms the smaller the amplitude. We have also tested the potential role of the serotonergic 5-HT2A cascade in visual hallucinations in Parkinson’s with these symptoms, following the receptor trafficking hypothesis. We did so with a pilot study in healthy controls (N=18) providing support for the role of the Gi/o-dependent pathway in the psychedelic effect and a case series in patients with Parkinson’s and visual hallucinations (N=5) using a double-blind crossover design. Positive results on psychosis scores and mismatch amplitude add further to the potential role of serotonergic modulation of visual hallucinations in Parkinson’s disease.

Acupuncture-assisted therapy for prolonged disorders of consciousness: study protocol for a randomized, conventional-controlled, assessor-and-statistician-blinded trial.

Acupuncture is a promising non-pharmaceutical complementary therapy in treating prolonged Disorders of consciousness (pDOC), but solid evidence to support its effectiveness and safety is still lacking. Thus, the purpose of this study is to investigate the efficacy and safety of acupuncture-assisted therapy for pDOC patients. A single-center, prospective, randomized, conventional-controlled, assessor-and-statistician-blinded trial has been designed and is being conducted at West China Hospital of Sichuan University. A total of 110 participants will be randomly assigned to the experimental group and the control group in a 1:1 allocation ratio and evaluated using Coma Recovery Scale-Revised (CRS-R) at 8 a.m., 12 p.m., and 4 p.m. on 2 consecutive days before enrollment to determine the consciousness level. The experimental group will receive acupuncture combined with conventional treatment, while the control group will receive only conventional treatment during the trial observation period. The treatment duration of both groups will be 20 days. Among them, the frequency of acupuncture-assisted therapy is once a day, with 10 consecutive sessions followed by a day's rest for a total of 24 days. Data will be collected separately during baseline and after the final treatment. For data analysis, both Full Analysis Set (FAS) and Per Protocol Set (PPS) principles will be performed together by applying SPSS 27.0 software. The primary outcome measures are the changes of CRS-R before and after treatment, while the secondary outcome measures are the changes of Full Outline of Unresponsiveness Scale (FOUR), the changes of Nociception Coma Scale-Revised (NCS-R), the changes of Disability Rating Scale (DRS), the changes of Mismatch Negativity (MMN) and P300 before and after treatment, respectively. This trial aims to rationally assess the consciousness level from multiple 2 perspectives through subjective evaluation and objective detection by selecting several standardized clinical scales combined with Event-Related Potential (ERP) detection technology. In this way, we will be able to reduce the subjectivity of consciousness assessment and objectively evaluate the clinical efficacy of acupuncture-assisted therapy for pDOC. The study, if proven to be effective and safe enough, will provide a favorable evidence to guide medical decision-making choices and future researches. https://www.chictr.org.cn/, identifier ChiCTR2300076180.

Early Auditory Temporal Processing Deficit in Children with Autism Spectrum Disorder: The Research Domain Criteria Framework.

Altered sensory processing especially in the auditory system is considered a typical observation in children with autism spectrum disorder (ASD). Auditory temporal processing is known to be impaired in ASD children. Although research suggests that auditory temporal processing abnormalities could be responsible for the core aspects of ASD, few studies have examined early time processing and their results have been conflicting. The present event-related potential (ERP) study investigated the early neural responses to duration and inter-stimulus interval (ISI) deviants in nonspeech contexts in children with ASD and a control group of typically developing (TD) children matched in terms of age and IQ. A passive auditory oddball paradigm was employed to elicit the mismatch negativity (MMN) for change detection considering both the duration and ISI-based stimulus. The MMN results showed that the ASD group had a relatively diminished amplitude and significant delayed latency in response to duration deviants. The findings are finally discussed in terms of hyper-hyposensitivity of auditory processing and the fact that the observed patterns may potentially act as risk factors for ASD development within the research domain criteria (RDoC) framework.

Differing Pattern of Mismatch Negativity Responses in Clinical and Nonclinical Voice Hearers Challenge Predictive Coding Accounts of Psychosis

BackgroundAmong people with schizophrenia (PSZ), reduced mismatch negativity (MMN) is conceptualized as evidence of disrupted prediction error signaling that underlies positive symptoms. However, this conceptualization has been challenged by observations that MMN and positive symptoms are often uncorrelated. In the current study, we tested the hypothesis that reduced MMN is associated with the presence of hallucinations and delusions specifically rather than the presence of a psychiatric illness. A second aim was to determine whether the strength of the association with positive symptoms increases for indices that reflect predictions at higher levels of abstraction. MethodsFifty-six PSZ, 34 nonclinical voice hearers, and 48 healthy comparison subjects (HCs) completed 2 MMN paradigms: one with a simple duration deviant type, and one with a higher-level, pattern-violation deviant type. We also measured the repetition positivity, which reflects the formation of auditory memory traces. ResultsWe observed that although PSZ exhibited the expected pattern of significantly reduced simple duration deviant type and reduced pattern-violation deviant type at the trend level compared with HCs, nonclinical voice hearers exhibited a pattern of simple duration deviant type and pattern-violation deviant type amplitude that was statistically similar to that of HCs (ps > .64). Similarly, PSZ exhibited a significantly reduced repetition positivity slope compared with HCs in the duration condition and a trend-level reduction compared with HCs in the pattern-violation condition. Nonclinical voice hearers did not differ from either group in repetition positivity slope in either condition. ConclusionsThese results indicate that the MMN as a prediction error signal does not reflect processes relevant for the manifestation of hallucinations and delusions.

Skin Carotenoids Are Related to Cognitive Abilities among Toddlers

BackgroundCarotenoids are antioxidant pigments that deposit in human tissues (e.g., skin, macula, and brain) upon dietary consumption. The health implications of skin carotenoids, which reflect overall dietary carotenoid consumption, have not been adequately studied in younger populations. ObjectivesThis work aimed to examine links between skin carotenoids and cognitive, language, and motor skills among toddlers. A secondary aim explored relationships between skin carotenoids and neurophysiologic outcomes of sensory memory [i.e., mismatch negativity (MMN)] and the functional integrity of the visual pathway [i.e., visual evoked potentials (VEPs)]. MethodsToddlers aged 12–18 mo (n = 45) were included in a cross-sectional study. Skin carotenoids were measured with reflection spectroscopy via the Veggie Meter®. Cognitive, language, and motor skills were measured using the Bayley Scale of Infant and Toddler Development IV Screening Test (BSID-IV). MMN and VEPs were collected with an auditory oddball task and a pattern reversal task, respectively, using electroencephalography. Analyses adjusted for age, household income, highest level of parental education, and total carotenoid intake (mg/1000 kcal). ResultsRegression modeling revealed that skin carotenoids significantly related to cognition (β = 0.24; P = 0.04) and not to any other BSID-IV subsets. Neither MMN nor VEP outcomes significantly related to skin carotenoids. ConclusionsGreater skin carotenoids were selectively related to cognition, indicating that carotenoids may play a role in cognition in toddlers. Additional research is needed to understand links between skin carotenoids and specific domains of cognitive function and brain health in early life.

Native language background affects the perception of duration and pitch

Estonian is a quantity language with both a primary duration cue and a secondary pitch cue, whereas Chinese is a tonal language with a dominant pitch use. Using a mismatch negativity experiment and a behavioral discrimination experiment, we investigated how native language background affects the perception of duration only, pitch only, and duration plus pitch information. Chinese participants perceived duration in Estonian as meaningless acoustic information due to a lack of phonological use of duration in their native language; however, they demonstrated a better pitch discrimination ability than Estonian participants. On the other hand, Estonian participants outperformed Chinese participants in perceiving the non-speech pure tones that resembled the Estonian quantity (i.e., containing both duration and pitch information). Our results indicate that native language background affects the perception of duration and pitch and that such an effect is not specific to processing speech sounds.

Intraindividual Variability of Event-Related Potentials in Psychosis: A Registered Report

BackgroundNeurophysiological tools have yielded valuable insights into the pathophysiology and treatment of psychosis. However, studies using event-related potentials (ERPs) primarily focus on mean scores and neglect within-person variability of ERP scores. The neglect of within-person variability of ERPs in the search for biomarkers might result in missed crucial differences related to psychosis. This registered report aimed to determine whether distinct patterns of intraindividual variability in ERP biomarkers are observed in people with a lifetime psychosis diagnosis. MethodsPublicly available data posted to the NIMH Data Archive for 1R01MH110434-01 was obtained for 162 patients with a lifetime history of psychosis and 178 never-psychotic controls. Participants completed tasks that measured auditory mismatch negativity (MMN), P300, error-related negativity (ERN), and reward positivity (RewP). Multilevel location-scale models were used to determine whether patients show greater intraindividual variability of ERP scores than controls. ResultsContrary to predictions, groups did not differ in within-person variability of MMN-frequency, P3, or ERN; patients showed less variability in MMN-duration than controls. Exploratory analyses of a subset of patients with schizophrenia showed greater variability in this group than in controls for MMN. Greater severity of thought disorder and activation symptoms were associated with higher intraindividual MMN variability. DiscussionDistinct patterns of intraindividual variability in the measured ERPs were not observed for the broad group of people with lifetime psychotic disorders. Exploratory analyses suggest that intraindividual differences in ERPs are more relevant to schizophrenia and certain symptom dimensions than to psychotic disorders broadly, but research is needed to confirm these exploratory findings.

Interaction between BDNF Val66Met polymorphism and mismatch negativity for working memory capacity in schizophrenia

Both the brain-derived neurotrophic factor (BDNF) valine (Val)/methionine (Met) polymorphism and mismatch negativity (MMN) amplitude are reportedly linked to working memory impairments in schizophrenia. However, there is evident scarcity of research aimed at exploring the relationships among the three factors. In this secondary analysis of a randomized, controlled, double-blind trial, we investigated these relationships. The trial assessed the efficacy of transcranial direct current stimulation for enhancing working memory in clinically stable schizophrenia patients, who were randomly divided into three groups: dorsolateral prefrontal cortex stimulation, posterior parietal cortex stimulation, and sham stimulation groups. Transcranial direct current stimulation was administered concurrently with a working memory task over five days. We assessed the BDNF genotype, MMN amplitude, working memory capacity, and interference control subdomains. These assessments were conducted at baseline with 54 patients and followed up post-intervention with 48 patients. Compared to BDNF Met-carriers, Val homozygotes exhibited fewer positive and general symptoms and increased working memory capacity at baseline. A correlation between MMN amplitude and working memory capacity was noted only in BDNF Val homozygotes. The correlations were significantly different in the two BDNF genotype groups. Furthermore, in the intervention group that showed significant improvement in MMN amplitude, BDNF Val homozygotes exhibited greater enhancement in working memory capacity than Met-carriers. This study provides in vivo evidence for the interaction between MMN and BDNF Val/Met polymorphism for working memory capacity. As MMN has been considered a biomarker of N-methyl-D-aspartate receptor (NMDAR) function, these data shed light on the complex interactions between BDNF and NMDAR in terms of working memory in schizophrenia.

Migraine versus tension-type headache in automatic emotional processing: A visual mismatch negativity study

ObjectiveIt is important to discriminate different headaches in clinical practice, and neurocognitive biomarkers may serve as objective tools. Several reports have suggested potential cognitive impairment for primary headaches, whereas cognitions within specific domains remain elusive, e.g., emotional processing. In this study, we aimed to characterize processing of facial expressions in migraine and tension-type headache (TTH) by analyzing expression-related visual mismatch negativity (EMMN) and explored whether their processing patterns were distinct. MethodsAltogether, 73 headache patients (20 migraine with aura (MA), 28 migraine without aura (MwoA), 25 TTH) and 27 age-matched healthy controls were recruited. After a battery of mood/neuropsychological evaluations, an expression-related oddball paradigm containing multiple models of neutral, happy and sad faces was used to investigate automatic emotional processing. ResultsWe observed cognitive impairment in all headache patients, especially in attention/execution subdomains, but no discrepancy existed among different headaches. Although analyses of P1/N170 did not reach significant levels, amplitude of early and late EMMN was markedly diminished in MA and MwoA compared with controls and TTH, regardless of happy or sad expression. Moreover, sad EMMN was larger (more negative) than happy EMMN only in controls, while not in all headache groups. ConclusionsOur findings implied that migraine, rather than TTH, might lead to more severe impairment of automatic emotional processing, which was manifested as no observable EMMN elicitation and disappearance of negative bias effect. The EMMN component could assist in discrimination of migraine from TTH and diagnosis of undefined headaches, and its availability needed further validations.

Examining the Complex Mismatch Negativity in Early Phase Psychosis Using the Dual Rule Paradigm.

Using electroencephalography (EEG) to examine the simple mismatch negativity (MMN), a marker of auditory cortex function, has been of great interest in the exploration of biomarkers for psychotic illness. Despite many studies reporting MMN deficits in chronic schizophrenia, there are inconsistent reports of MMN reductions in the early phases of psychotic illness, suggesting the MMN elicited by traditional paradigms may not be a sensitive enough measure of vulnerability to be used as a biomarker. Recently, a more computationally complex measure of auditory cortex function (the complex mismatch negativity; cMMN) has been hypothesized to provide a more sensitive marker of illness vulnerability. The current study employed a novel dual rule paradigm, in which two pattern rules are established and violated, to examine the cMMN in 14 individuals with early phase psychosis (EPP, < 5 years illness) and 15 healthy controls (HC). Relationships between cMMN waveforms, symptom severity, and measures of functioning were explored. We found reductions of cMMN amplitudes at the site of maximal amplitude in EPP (p = .017) with large effect sizes (Hedges' g = 0.96). This study is an early step in the exploration of the cMMN as a biomarker for psychosis. Our results provide evidence that the dual rule cMMN paradigm shows promise as a method for cMMN elicitation that captures more subtle neurofunctional changes in the early stages of illness.

Experience with the cochlear implant enhances the neural tracking of spectrotemporal patterns in the Alberti bass

Cochlear implant (CI) users experience diminished music enjoyment due to the technical limitations of the CI. Nonetheless, behavioral studies have reported that rhythmic features are well-transmitted through the CI. Still, the gradual improvement of rhythm perception after the CI switch-on has not yet been determined using neurophysiological measures. To fill this gap, we here reanalyzed the electroencephalographic responses of participants from two previous mismatch negativity studies. These studies included eight recently implanted CI users measured twice, within the first six weeks after CI switch-on and approximately three months later; thirteen experienced CI users with a median experience of 7 years; and fourteen normally hearing (NH) controls. All participants listened to a repetitive four-tone pattern (known in music as Alberti bass) for 35 min. Applying frequency tagging, we aimed to estimate the neural activity synchronized to the periodicities of the Alberti bass. We hypothesized that longer experience with the CI would be reflected in stronger frequency-tagged neural responses approaching the responses of NH controls. We found an increase in the frequency-tagged amplitudes after only 3 months of CI use. This increase in neural synchronization may reflect an early adaptation to the CI stimulation. Moreover, the frequency-tagged amplitudes of experienced CI users were significantly greater than those of recently implanted CI users, but still smaller than those of NH controls. The frequency-tagged neural responses did not just reflect spectrotemporal changes in the stimuli (i.e., intensity or spectral content fluctuating over time), but also showed non-linear transformations that seemed to enhance relevant periodicities of the Alberti bass. Our findings provide neurophysiological evidence indicating a gradual adaptation to the CI, which is noticeable already after three months, resulting in close to NH brain processing of spectrotemporal features of musical rhythms after extended CI use.

MEG Microstates: An Investigation of Underlying Brain Sources and Potential Neurophysiological Processes

Microstates are transient scalp configurations of brain activity measured by electroencephalography (EEG). The application of microstate analysis in magnetoencephalography (MEG) data remains challenging. In one MEG dataset (N = 113), we aimed to identify MEG microstates at rest, explore their brain sources, and relate them to changes in brain activity during open-eyes (ROE) or closed-eyes resting state (RCE) and an auditory Mismatch Negativity (MMN) task. In another dataset of simultaneously recorded EEG-MEG data (N = 21), we investigated the association between MEG and EEG microstates. Six MEG microstates (mMS) provided the best clustering of resting-state activity, each linked to different brain sources: mMS 1–2: left/right occipito-parietal; mMS 3: fronto-temporal; mMS 4: centro-medial; mMS 5–6: left/right fronto-parietal. Increases in occipital alpha power in RCE relative to ROE correlated with greater mMS 1–2 time coverage (τbs < 0.20, ps > .002), while the lateralization of deviance detection in MMN was associated with mMS 5–6 time coverage (τbs < 0.16, ps > .012). No temporal correlation was found between EEG and MEG microstates (ps > .05), despite some overlap in brain sources and global explained variance between mMS 2–3 and EEG microstates B-C (rs > 0.60, ps < .002). Hence, the MEG signal can be decomposed into microstates, but mMS brain activity clustering captures phenomena different from EEG microstates. Source reconstruction and task-related modulations link mMS to large-scale networks and localized activities. Thus, mMSs offer insights into brain dynamics and task-specific processes, complementing EEG microstates in studying physiological and dysfunctional brain activity.