Functional connectivity of the frontotemporal network in preattentive detection of abstract changes: Perturbs and observes with transcranial magnetic stimulation and event‐related optical signal

Current theories of automatic or preattentive change detection suggest a regularity or prediction violation mechanism involving functional connectivity between the inferior frontal cortex (IFC) and the superior temporal cortex (STC). By disrupting the IFC function with transcranial magnetic stimulation (TMS) and recording the later STC mismatch response with event‐related optical signal (EROS), previous study demonstrated a causal IFC‐to‐STC functional connection in detecting a pitch or physical change. However, physical change detection can be achieved by memory comparison of the physical features and may not necessarily involve regularity/rule extraction and prediction. The current study investigated the IFC–STC functional connectivity in detecting rule violation (i.e., an abstract change). Frequent standard tone pairs with a constant relative pitch difference, but varying pitches, were presented to establish a pitch interval rule. This abstract rule was violated by deviants with reduced relative pitch intervals. The EROS STC mismatch response to the deviants was abolished by the TMS applied at the IFC 80 ms after deviance onset, but preserved in the spatial (TMS on vertex), auditory (TMS sound), and temporal (200 ms after deviance onset) control conditions. These results demonstrate the IFC–STC connection in preattentive abstract change detection and support the regularity or prediction violation account.     

Finding the right control: The mismatch negativity under investigation

ObjectiveWhen investigating auditory perceptual regularity processing, mismatch negativity (MMN) is commonly used. MMN is computed as a difference signal between the event-related potentials (ERPs) elicited by repeated standard tones and rarely occurring deviant tones. This procedure leads to an underestimation of the N1 component elicited by standards compared to the N1 to deviants which might affect the MMN. Consequently, a random control design was previously introduced. This design, however, overestimates the N1 to the deviant. Here, we developed a new paradigm that avoids previous drawbacks.MethodsWe designed a regular cascadic sequence as a control to the deviant. ERPs were measured while presenting conventional oddball blocks (standards, deviants), random control blocks and a cascadic control block.ResultsMMN was observed in each difference signal. Regarding the N1, standards elicited smallest amplitudes. The N1 for the deviant and the cascadic control was comparable. The largest N1 was elicited by the random control.ConclusionStandards underestimate N1 refractoriness effects in the responses to deviants, while random control tones overestimate. Cascadic control tones, however, provide a reasonable estimation for the N1.SignificanceThe new cascadic control design is suitable to investigate auditory perceptual regularity processes while controlling for N1 refractoriness effects.     

The role of large-scale memory organization in the mismatch negativity event-related brain potential

The mismatch negativity (MMN) component of event-related brain potentials is elicited by infrequent changes in regular acoustic sequences even if the participant is not actively listening to the sound sequence. Therefore, the MMN is assumed to result from a preattentive process in which an incoming sound is checked against the automatically detected regularities of the auditory sequence and is found to violate them. For example, presenting a discriminably different (deviant) sound within the sequence of a repetitive (standard) sound elicits the MMN. In the present article, we tested whether the memory organization of the auditory sequence can affect the preattentive change detection indexed by the MMN. In Experiment 1, trains of six standard tones were presented with a short, 0.5-sec stimulus onset asynchrony (SOA) between tones in the train. This was followed by a variable SOA between the last standard and the deviant tone (the "irregular presentation" condition). Of 12 participants displaying an MMN at the 0.5-sec predeviant SOA, it was elicited by 11 with the 2-sec predeviant SOA, in 5 participants with the 7-sec SOA, and in none with the 10-sec SOA. In Experiment 2, we repeated the 7-sec irregular predeviant SOA condition, along with a "regular presentation" condition in which the SOA between any two tones was 7 sec. MMN was elicited in about half of the participants (9 out of 16) in the irregular presentation condition, whereas in the regular presentation condition, MMN was elicited in all participants. These results cannot be explained on the basis of memory-strength decay but can be interpreted in terms of automatic, auditory preperceptual grouping principles. In the irregular presentation condition, the close grouping of standards may cause them to become irrelevant to the mismatch process when the deviant tone is presented after a long silent break. Because the MMN indexes preattentive auditory processing, the present results provide evidence that large-scale preperceptual organization of auditory events occurs despite attention being directed away from the auditory stimuli.     

Reduced suppression or labile memory? Mechanisms of inefficient filtering of irrelevant information in older adults

Cognitive aging theories emphasize the decrease in efficiency of inhibitory processes and attention control in normal aging, which, in turn, may result in reduction of working memory function. Accordingly, some of these age-related changes may be due to faster sensory memory decay or to inefficient filtering of irrelevant sensory information (sensory gating). Here, event-related brain potentials and the event-related optical signal were recorded in younger and older adults passively listening to tone trains. To determine whether age differentially affects decay of sensory memory templates over short intervals, trains were separated by delays of either 1 or 5 sec. To determine whether age affects the suppression of responses to unattended repeated stimuli, we evaluated the brain activity elicited by successive train stimuli. Some trains started with a shorter-duration stimulus (deviant trains). Results showed that both electrical and optical responses to tones were more persistent with repeated stimulation in older adults than in younger adults, whereas the effects of delay were similar in the two groups. A mismatch negativity (MMN) was elicited by the first stimulus in deviant trains. This MMN was larger for 1- than 5-sec delay, but did not differ across groups. These data suggest that age-related changes in sensory processing are likely due to inefficient filtering of repeated information, rather than to faster sensory memory decay. This inefficient filtering may be due to, or interact with, reduced attention control. Furthermore, it may increase the noise levels in the information processing system and thus contribute to problems with working memory and speed of processing.     

Temporo-frontal phase synchronization supports hierarchical network for mismatch negativity

ObjectiveWe performed an experiment designed to reveal the brain-regional network dynamics underlying both automatic and intentional auditory change detection as typically indexed by the mismatch negativity (MMN) event-related potential (ERP).MethodsHigh-density EEG was recorded while participants heard a stream of standard pure tones, into which occasional (14%) frequency deviants were inserted. In a first run they listened passively while watching a closed-captioned movie, whereas in a second run they pressed a button each time they detected a deviant while watching the movie with neither sound nor captioning.ResultsIndependent component analysis revealed independent components that we localized to temporal and frontal regional brain sources relevant to the generation of the MMN. Relative power in various oscillatory frequency bands, computed from a wavelet analysis on the time series of these independent components, was modulated by task demands and stimulus type, as was dynamic phase-locking between pairs of the independent components in those same frequency bands.ConclusionThese results support a hierarchical model of MMN generation that emphasizes information processing and transfer between temporal and frontal brain regions.SignificanceIn addition to enhancing the use of the MMN to evaluate some aspects of central auditory functioning, these results could be important for the evaluation of alterations in other cognitive functions or in consciousness.     

Effects of sequential and temporal probability of deviant occurrence on mismatch negativity

The mismatch negativity (MMN) increases in amplitude as the probability of deviant occurrence decreases. It is unclear whether the determining variable is sequential probability (i.e. the probability of a deviant within a number of standards) or temporal probability (i.e. the probability of a deviant within a period of time). Eight subjects heard a train of frequently occurring 1000 Hz standard tones. The probability of a 1100 Hz pitch deviant was manipulated. In one condition the stimulus-onset-asynchrony (SOA) was 150 ms, with temporal probability of deviant occurrence being either 1/9.00, 1/4.50, 1/2.25, or 1/1.125 s (sequential probability being 1/60, 1/30, 1/15, or 1(deviant)/7.5(standards), respectively). In another condition the SOA was 600 ms, with temporal probability being either 1/9.00, 1/4.50, or 1/2.25 s (sequential probability being 1/15, 1/7.5, or 1/3.75, respectively). In a final condition, the SOA was 2400 ms with temporal probability being 1/9.00 s (sequential probability 1/3.75). Both sequential and temporal probabilities had a marked effect on the MMN. When a deviant occurred every 2.25, 4.50, or 9.00 s, the MMN increased as temporal probability decreased. When a deviant occurred once every 7.5 or 15 standards, the MMN was larger for lower sequential probability, but the effect was not significant. Nevertheless, when temporal probability was held constant at 1/9.00 s, the MMN increased as sequential probability decreased. At rapid rates of stimulus presentation, the MMN was largest. However, it was attenuated when the probability of deviant occurrence was very high perhaps due to the refractoriness of its generator. At the slowest rate, the MMN was diminished perhaps due to memory decay for the standard stimuli.     

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

ObjectiveVerify and explore unexpected results suggesting an effect of deviance direction (shorter or longer deviants) on the amplitude of MMNs evoked by sound duration contrasts.MethodsMMNs were recorded using the oddball paradigm on ten adults. Four standard stimulus durations (100, 150, 200 and 250 ms) were used and deviants were 50% shorter or longer. Behavioral data (hit rates, d′, and reaction times) were collected after the electrophysiological sessions.ResultsMMNs were larger for short than for long deviants. There was no effect on MMN latencies. Hit rates and d′ data were almost at ceiling level for all conditions even for the longest standard – long deviant combination in which the MMN was abolished.ConclusionsWe argue that the deviance direction effect on MMN amplitudes can be explained by the delay between the moment of deviance detection and the end of the deviance quantification process.SignificanceA major effect of deviance direction on amplitudes was confirmed. This effect, which was confined to electrophysiological data, is to be taken into account when using duration contrasts to probe the processing of temporal information.     

The right profile: mismatch negativity in schizophrenia with and without auditory hallucinations as measured by a multi-feature paradigm.

ObjectiveTo examine pre-attentive acoustic change detection in schizophrenia patients with and without auditory hallucinations via mismatch negativity (MMN) extracted from a multi-feature paradigm.MethodsThis study examined the electroencephalograph (EEG)-derived MMN, recorded across 32 sites, in 12 hallucinating patients (HPs) with schizophrenia, 12 non-hallucinating patients (NPs) with schizophrenia and 12 healthy controls (HCs). MMN was recorded in response to a multi-feature MMN paradigm [Näätänen, R., et al., 2004. The mismatch negativity (MMN): towards the optimal paradigm. Clin. Neurophys. 115, 140–144] which employs frequency, duration, intensity, location and gap deviants. Differences in source localization were probed using standardized low resolution brain electromagnetic tomography (sLORETA).ResultsHPs showed significantly smaller MMNs to duration deviants compared to HCs and NPs, as well as smaller MMNs to intensity deviants compared to HCs. Regionalized differences between HCs and each of the patient groups were observed in response to frequency deviants. There were no significant group effects for location or gap deviants, or for MMN latency. Source localization using sLORETA showed no significant differences in MMN generator location across groups for any of the deviant stimuli.ConclusionsThe often-reported robust MMN deficit to duration deviants may be specific to schizophrenia patients afflicted with auditory hallucinations. Furthermore, by using symptom-specific groups, novel deficits of pre-attentive auditory processing, such as that observed to intensity deviants in HPs, may be revealed.SignificanceThe differential responding observed between both groups of patients with schizophrenia has implications for automatic processing within the auditory cortex of hallucinating patients and suggests that care must be taken when recruiting participants in studies involving schizophrenia to ensure consistent, replicable results.     

Mismatch negativity to different deviant changes in autism spectrum disorders: A meta-analysis

ObjectiveMismatch negativity (MMN) has been continuously used to evaluate the functional integrity of central auditory processing. However, it still remains inconclusive whether patients with autism spectrum disorder (ASD) demonstrate reduced MMN responses in all deviant types.MethodsTo reconcile the previous controversial findings, we performed a meta-analysis of peer-reviewed MMN articles concerning ASD. The potential moderators regarding different deviant types, diagnosis, and age on the effect sizes (Hedges’ g) were also assessed.ResultsCompared to the controls, ASD patients showed reduced MMN amplitudes (g = −0.37, p = 0.001) and prolonged latencies (g = −0.33, p = 0.041) in response to speech-sound deviants. Children/adolescents with ASD manifested reduced MMN amplitudes in response to tone-duration deviants (g = −0.46, p = 0.014). Furthermore, the results showed significantly shortened MMN latencies to tone-frequency deviants in patients with autism (g = 0.29, p = 0.038) and, in contrast, prolonged MMN latencies (g = −0.74, p = 0.001) in patients with Asperger syndrome.ConclusionMMN deficits are robust in ASD patients, suggesting an altered central ability in auditory discrimination.SignificanceMMN alterations were displayed in different profiles with respect to frequency, duration and phoneme changes.     

Hemispheric specialization during discrimination of sound sources reflected by MMN

The present study reports the hemispheric specificity of spatial auditory processing in 15 healthy subjects by measuring location mismatch negativity (MMN) under free field stimulation. The aim was to decide between the partly inconsistent hypotheses of contralateral and/or right-hemispheric dominance in spatial processing in the auditory cortex. The laterality of deviant-standard positions were systematically varied covering the whole of the frontal hemifield from 90° left to 90° right, while the spatial separation of deviant and standard were fixed at 17°. This enabled the evaluation of the specific location-MMNs relating to distinct cortical processing of acoustic space. The inter-hemispheric comparison of the amplitudes of MMNs showed that spatial deviation towards the periphery at −/+17° (relative to 0°-standard) and at −/+90° (relative to −/+73°-standard) elicited a salient contralateral activation. In contrast, positional changes towards front at −/+56°-positions (relative to −/+73°-standard) resulted equal bilateral MMNs. Further, MMN latencies became longer with increasing laterality of respective deviant-standard pairs. Thus, the present study suggests a contralateral pre-attentive cortical processing of acoustic space information in the free field. The direction of positional changes (‘towards periphery’ vs. ‘towards front’) seems to augment or reduce this contralateral effect. The sound source discrimination performance across space is mirrored by the location-MMN latency.     

Memory-based mismatch response to changes in duration of auditory stimuli: An MEG study

ObjectiveDifferences in physical features and occurrence probability between standards and deviants in oddball paradigms provide contributions to magnetic mismatch negativity (MMNm). We aimed to reduce these influential factors and extract memory-based MMNm by adding a control paradigm.MethodsMagnetoencephalographic responses were recorded in 13 healthy adults with an oddball paradigm (125-ms standard and 50-ms deviant tones) and an equiprobable control paradigm (50-ms control and four other duration-varying tones). The stimulus onset asynchrony was 500 ms. Controlled MMNm was obtained by subtracting control-evoked responses from deviant-evoked responses.ResultsWith respect to the onset of stimulus difference, the peak latency of controlled MMNm was compatible with previous intracranial MMN recordings. Both controlled and traditional MMNm were generated around the superior temporal cortex, whereas the controlled MMNm amplitude was about 70% of traditional MMNm amplitude. Right-hemispheric dominance was observed in traditional MMNm but not in controlled MMNm. N100m amplitude was smaller in standard-evoked than in deviant- or control-evoked responses.ConclusionsControlled MMNm reflects memory-based processing of duration changes, whereas traditional MMNm additionally involves non-memory activations related to differential refractoriness states and physical properties between standard and deviant stimuli.SignificanceThe memory-based processing of auditory deviants may be preferentially extracted by adding a control paradigm.     

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.     

The mismatch negativity (MMN) with no standard stimulus

ObjectiveThe recent fast multi-feature mismatch negativity (MMN) paradigms rest on the assumption that the deviant stimuli, alternating with the standard tone, strengthen the memory trace of the standard in respect to those attributes they have in common. In the present study, we tested whether the MMN can be recorded even without the standard stimulus, with the invariant properties of the deviant stimuli serving as a standard against which to detect the sound changes.MethodsMMN was recorded for changes in sound duration, frequency, intensity, location, gap, brightness, density, and noise level in a new multi-feature paradigm where no standard stimuli were used. In addition, these MMNs were compared with those recorded in the conventional multi-feature paradigm.ResultsAll sound changes elicited significant MMN responses that were highly similar between paradigms.ConclusionsThe MMN can be recorded even without the standard stimulus, as an accurate memory trace is constructed for the invariant features of the auditory input.SignificanceOmitting the standard stimuli results in almost 50% shorter recording time and the larger selection of deviant types with the newly introduced brightness, density, and noise-level changes provides even more information on the individual perceptual profiles than conventional multi-feature paradigms.     

Emotional MMN: Anxiety and heart rate correlate with the ERP signature for auditory change detection

ObjectivePrevious work established the mismatch negativity (MMN) as a correlate of pre-attentive auditory change detection. The present study aimed at investigating the relationship between the MMN and emotional processes associated with the detection of change.MethodsTo this end, we assessed state anxiety with a questionnaire and subsequently recorded the electroencephalogram (EEG) and heart rate while participants watched a silent movie and listened to a task-irrelevant auditory oddball sequence. The oddball sequence comprised meaningless syllables of which some were deviants spoken with an angry or neutral voice.ResultsThe MMN to angry voice deviants was larger than that to neutral deviants and correlated positively with ensuing heart rate acceleration. Additionally, both the MMN and heart rate acceleration to angry voice deviants were increased with increasing state anxiety. A similar effect for neutral voice deviants was non-significant.ConclusionTaken together, these results suggest that the pre-attentive processing of threat, as reflected by the MMN, is linked to an activation of the sympathetic nervous system. Moreover, this link is more strongly activated in individuals with high state anxiety.SignificanceThus, the MMN may be used as a marker for an individual’s state dependent sensitivity to unattended, emotionally relevant change.     

The neurophysiological basis of the integration of written and heard syllables in dyslexic adults

ObjectiveLetter-speech sound integration in fluent readers takes place automatically and is dependent on temporal synchrony between letters and sounds. In developmental dyslexia, however, letter-speech sound associations are hard to learn, compromising accurate and fluent reading. We studied the effect of printed text on processing speech sounds in dyslexic and fluent adult readers.MethodsVisual stimuli were presented with sequences of spoken syllables including vowel or consonant changes, or changes in syllable intensity, frequency, or vowel duration. As visual material, written syllables or their scrambled images were used. The auditory stimuli were presented either synchronously with the visual stimuli or time delayed. The mismatch negativity (MMN), an index of automatic neural change detection, was recorded.ResultsMMN amplitudes were larger to syllable changes in combination with written syllables than with scrambled images in fluent readers. However, dyslexic readers showed no difference between syllables vs. scrambled image condition. Furthermore, MMNs to consonant and frequency changes peaked later in dyslexic than fluent readers.ConclusionsOur results suggest deficient and sluggish audiovisual integration in dyslexic individuals, which is not dependent on the phonological relevance of the deviant type.SignificanceUnlike previous studies, our study included several different types of syllable changes presented with concurrent print, enabling us to determine in more detail the nature of the audiovisual deficit in dyslexia.     

Right hemisphere dominance of different mismatch negativities

Auditory stimulus blocks were presented to 10 reading subjects. Each block consisted of 2 types of stimulus, standard (P = 90%) and deviant (P = 10%), delivered in a random order with short constant inter-stimulus intervals. The standard stimuli were 600 Hz, 80 dB SPL 50 msec sine wave bursts. In different blocks, the deviant stimuli differed from the standards either in frequency (650 Hz), intensity (70 dB) or duration (20 msec). Left- and right-ear stimulations were used in separate blocks. Event-related brain potentials (ERPs) were recorded with 16 electrodes over both hemispheres. All the different types of deviant stimuli elicited an ERP component called the mismatch negativity (MMN). The MMN was larger over the right hemisphere irrespective of the ear stimulated whereas the N1 component, elicited by both standards, and deviants, was larger over the hemisphere contralateral to the ear stimulated. The results provide further evidence for the view that the MMN reflects a neural mismatch process with a memory trace which automatically codes the physical features of the repetitive stimuli.     

Altered neocortical tactile but preserved auditory early change detection responses in Friedreich ataxia

ObjectiveTo study using magnetoencephalography (MEG) the spatio-temporal dynamics of neocortical responses involved in sensory processing and early change detection in Friedreich ataxia (FRDA).MethodsTactile (TERs) and auditory (AERs) evoked responses, and early neocortical change detection responses indexed by the mismatch negativity (MMN) were recorded using tactile and auditory oddballs in sixteen FRDA patients and matched healthy subjects. Correlations between the maximal amplitude of each response, genotype and clinical parameters were investigated.ResultsEvoked responses were detectable in all FRDA patients but one. In patients, TERs were delayed and reduced in amplitude, while AERs were only delayed. Only tactile MMN responses at the contralateral secondary somatosensory cortex were altered in FRDA patients. Maximal amplitudes of TERs, AERs and tactile MMN correlated with genotype, but did not correlate with clinical parameters.ConclusionsIn FRDA, the amplitude of tactile MMN responses at SII cortex are reduced and correlate with the genotype, while auditory MMN responses are not altered.SignificanceSomatosensory pathways and tactile early change detection are selectively impaired in FRDA.     

Speech-feature discrimination in children with Asperger syndrome as determined with the multi-feature mismatch negativity paradigm

ObjectiveAsperger syndrome, belonging to the autistic spectrum of disorders, involves deficits in social interaction and prosodic use of language but normal development of formal language abilities. Auditory processing involves both hyper- and hypoactive reactivity to acoustic changes.MethodsResponses composed of mismatch negativity (MMN) and obligatory components were recorded for five types of deviations in syllables (vowel, vowel duration, consonant, syllable frequency, syllable intensity) with the multi-feature paradigm from 8–12-year old children with Asperger syndrome.ResultsChildren with Asperger syndrome had larger MMNs for intensity and smaller MMNs for frequency changes than typically developing children, whereas no MMN group differences were found for the other deviant stimuli. Furthermore, children with Asperger syndrome performed more poorly than controls in Comprehension of Instructions subtest of a language test battery.ConclusionsCortical speech-sound discrimination is aberrant in children with Asperger syndrome. This is evident both as hypersensitive and depressed neural reactions to speech-sound changes, and is associated with features (frequency, intensity) which are relevant for prosodic processing.SignificanceThe multi-feature MMN paradigm, which includes variation and thereby resembles natural speech hearing circumstances, suggests abnormal pattern of speech discrimination in Asperger syndrome, including both hypo- and hypersensitive responses for speech features.     

Lasting first impressions: a conservative bias in automatic filters of the acoustic environment

Even in the unattended auditory environment, what we learn first appears resistant to re-evaluation based on experience. Mismatch negativity (MMN) is an auditory event-related potential elicited to rare deviation from automatically generated predictions about the sound environment. MMN amplitude is thought to reflect the potential importance of a sound for further processing. This study was designed to explore the degree to which past experience with a sound can alter automatic attributions about that sound's importance. MMN was elicited to rare (p = .125) physical “deviants” amongst a sequence of highly probable (p = .875) “standard” sounds. Sound identity alternated across blocks within the sequence (i.e., the former deviant became the new standard and the former standard the new deviant). The time period over which a standard remained the more probable tone was varied over Fast (0.8 min), Medium (1.6 min) and Slow (2.4 min) change conditions. Given that local within-block probabilities remained constant across conditions, any change in MMN size was considered a reflection of more rostral brain regions enabling a longer time scale (across-block) representation of event-probability extraction. Larger MMNs were expected to deviations in blocks with longer standard-stability. Although a significant increase in MMN amplitude was observed with increased rule stability, MMN amplitude was heavily dependent on the initial sequence structure. A “primacy bias” was observed such that prolonged stability produced large increases in the MMN to deviations from the first established standard but substantially smaller MMN to this first standard as a later deviant. The primacy effect in these data implies that the automatic filtering of sound relevance is biased toward a confirmation of initial expectations. Initial experience therefore altered the perceived salience of subsequent events.     

Omission mismatch negativity of speech sounds reveals a functionally impaired temporal window of integration in schizophrenia

ObjectiveWe hypothesized that sensory memory associated with the temporal window of integration (TWI) would be impaired in patients with schizophrenia, an issue that had not been evaluated using omission mismatch negativity (MMN) of complex speech sounds. We aimed to assess the functional changes in auditory sensory memory associated with the TWI in patients with schizophrenia by investigating the effect of omission of complex speech stimuli on the MMN.MethodsIn total, 17 patients with schizophrenia and 15 control individuals participated in the study. The MMN in response to omission deviants of complex speech sounds was recorded, while the participants were instructed to ignore the series of speech sounds.ResultsThe MMN latency in patients with schizophrenia was significantly prolonged by deviant stimuli to omissions corresponding to the early and late parts of the temporal TWI. There were no significant group differences in the amplitude of the MMN to omissions at different time points across the TWI.ConclusionsOur results suggested that sensory tracing function in patients with schizophrenia is impaired in the early and the later half of the TWI.SignificanceWe showed that certain MMN abnormalities in patients with schizophrenia may be caused by an impaired TWI.