Activation of brain mechanisms of attention switching as a function of auditory frequency change

Neural and Behavioral Differences in Speech Perception for Children With Autism Spectrum Disorders Within an Audiovisual Context

PURPOSE

Reduced use of visible articulatory information on a speaker's face has been implicated as a possible contributor to language deficits in autism spectrum disorders (ASD). We employ an audiovisual (AV) phonemic restoration paradigm to measure behavioral performance (button press) and event-related potentials (ERPs) of visual speech perception in children with ASD and their neurotypical peers to assess potential neural substrates that contribute to group differences.

METHOD

Two sets of speech stimuli, /ba/-"/a/" ("/a/" was created from the /ba/ token by a reducing the initial consonant) and /ba/-/pa/, were presented within an auditory oddball paradigm to children aged 6-13 years with ASD (n = 17) and typical development (TD; n = 33) within two conditions. The AV condition contained a fully visible speaking face; the pixelated (PX) condition included a face, but the mouth and jaw were PX, removing all articulatory information. When articulatory features were present for the /ba/-"/a/" contrast, it was expected that the influence of the visual articulators would facilitate a phonemic restoration effect in which "/a/" would be perceived as /ba/. ERPs were recorded during the experiment while children were required to press a button for the deviant sound for both sets of speech contrasts within both conditions.

RESULTS

Button press data revealed that TD children were more accurate in discriminating between /ba/-"/a/" and /ba/-/pa/ contrasts in the PX condition relative to the ASD group. ERPs in response to the /ba/-/pa/ contrast within both AV and PX conditions differed between children with ASD and TD children (earlier P300 responses for children with ASD).

CONCLUSION

Children with ASD differ in the underlying neural mechanisms responsible for speech processing compared with TD peers within an AV context.

Children's inhibition skills are associated with their P3a latency-results from an exploratory study

BACKGROUND

The P3a response is thought to reflect involuntary orienting to an unexpected stimulus and has been connected with set-shifting and inhibition in some studies. In our exploratory study, we investigated if the amplitude and the latency of the P3a response were associated with the performance in a modified flanker task measuring inhibition and set-shifting in 10-year-old children (N = 42). Children participated in electroencephalography (EEG) measurement with an auditory multifeature paradigm including standard, deviating, and novel sounds. In addition, they performed a separate flanker task requiring inhibition and set-shifting skills.

RESULTS

The P3a latencies for deviant sounds were associated with the reaction time reflecting inhibition: the shorter the response latencies were, the faster the reaction time was. The P3a latencies for novel sounds were not linked to the reaction times reflecting either inhibition or set-shifting. In addition, the magnitude of the P3a response was not associated with the performance in the flanker task.

CONCLUSIONS

Our results suggest that P3a response latency and reaction speed reflecting inhibitory skills are based on shared neural mechanism. Thus, the present study brings new insight to the field investigating the associations between behavior and its neural indices.

Dimensionally Specific Attention Capture in Birds Performing Auditory Streaming Task

Previous studies in budgerigars (Melopsittacus undulatus) have indicated that they experience attention capture in a qualitatively similar way to humans. Here, we apply a similar objective auditory streaming paradigm, using modified budgerigar vocalizations instead of ABAB-… patterned pure tones, in the sound sequences. The birds were trained to respond to deviants in the target stream while ignoring the distractors in the background stream. The background distractor could vary among five different categories and two different sequential positions, while the target deviants could randomly appear at five different sequential positions and vary among two different categories. We found that unpredictable background distractors could deteriorate birds' sensitivity to the target deviants. Compared to conditions where the background distractor appeared right before the target deviant, the attention capture effect decayed in conditions when the background distractor appeared earlier. In contrast to results from the same paradigm using pure tones, the results here are evidence for a faster recovery from attention capture using modified vocalization segments. We found that the temporally modulated background distractor captured birds' attention more and deteriorated birds' performance more than other categories of background distractor, as the temporally modulated target deviant enabled the birds to focus their attention toward the temporal modulation dimension. However, different from humans, birds have lower tolerances for suppressing the distractors from the same feature dimensions as the targets, which is evidenced by higher false alarm rates for the temporally modulated distractor than other distractors from different feature dimensions.

Classification of First-Episode Schizophrenia, Chronic Schizophrenia and Healthy Control Based on Brain Network of Mismatch Negativity by Graph Neural Network

Mismatch negativity (MMN) has been consistently found deficit in schizophrenia, which was considered as a promising biomarker for assessing the impairments in pre-attentive auditory processing. However, the functional connectivity between brain regions based on MMN is not clear. This study provides an in-depth investigation in brain functional connectivity during MMN process among patients with first-episode schizophrenia (FESZ), chronic schizophrenia (CSZ) and healthy control (HC). Electroencephalography (EEG) data of 128 channels is recorded during frequency and duration MMN in 40 FESZ, 40 CSZ patients and 40 matched HC subjects. We reconstruct the cortical endogenous electrical activity from EEG recordings using exact low-resolution electromagnetic tomography and build functional brain networks based on source-level EEG data. Then, graph-theoretic features are extracted from the brain networks with the support vector machine (SVM) to classify FESZ, CSZ and HC groups, since the SVM has good generalization ability and robustness as a universally applicable nonlinear classifier. Furthermore, we introduce the graph neural network (GNN) model to directly learn for the network topology of brain network. Compared to HC, the damaged brain areas of CSZ are more extensive than FESZ, and the damaged area involved the auditory cortex. These results demonstrate the heterogeneity of the impacts of schizophrenia for different disease courses and the association between MMN and the auditory cortex. More importantly, the GNN classification results are significantly better than those of SVM, and hence the EEG-based GNN model of brain networks provides an effective method for discriminating among FESZ, CSZ and HC groups.

Attention capture in birds performing an auditory streaming task

Numerous animal models have been used to investigate the neural mechanisms of auditory processing in complex acoustic environments, but it is unclear whether an animal’s auditory attention is functionally similar to a human’s in processing competing auditory scenes. Here we investigated the effects of attention capture in birds performing an objective auditory streaming paradigm. The classical ABAB… patterned pure tone sequences were modified and used for the task. We trained the birds to selectively attend to a target stream and only respond to the deviant appearing in the target stream, even though their attention may be captured by a deviant in the background stream. When no deviant appeared in the background stream, the birds experience the buildup of streaming process in a qualitatively similar way as they did in a subjective paradigm. Although the birds were trained to selectively attend to the target stream, they failed to avoid the involuntary attention switch caused by the background deviant, especially when the background deviant was sequentially unpredictable. Their global performance deteriorated more with increasingly salient background deviants, where the buildup process was reset by the background distractor. Moreover, sequential predictability of the background deviant facilitated the recovery of the buildup process after attention capture. This is the first study that addresses the perceptual consequences of the joint effects of top-down and bottom-up attention in behaving animals.

A generic deviance detection principle for cortical On/Off responses, omission response, and mismatch negativity

Neural responses to sudden changes can be observed in many parts of the sensory pathways at different organizational levels. For example, deviants that violate regularity at various levels of abstraction can be observed as simple On/Off responses of individual neurons or as cumulative responses of neural populations. The cortical deviance-related responses supporting different functionalities (e.g., gap detection, chunking, etc.) seem unlikely to arise from different function-specific neural circuits, given the relatively uniform and self-similar wiring patterns across cortical areas and spatial scales. Additionally, reciprocal wiring patterns (with heterogeneous combinations of excitatory and inhibitory connections) in the cortex naturally speak in favor of a generic deviance detection principle. Based on this concept, we propose a network model consisting of reciprocally coupled neural masses as a blueprint of a universal change detector. Simulation examples reproduce properties of cortical deviance-related responses including the On/Off responses, the omitted-stimulus response (OSR), and the mismatch negativity (MMN). We propose that the emergence of change detectors relies on the involvement of disinhibition. An analysis of network connection settings further suggests a supportive effect of synaptic adaptation and a destructive effect of N-methyl-D-aspartate receptor (NMDA-r) antagonists on change detection. We conclude that the nature of cortical reciprocal wiring gives rise to a whole range of local change detectors supporting the notion of a generic deviance detection principle. Several testable predictions are provided based on the network model. Notably, we predict that the NMDA-r antagonists would generally dampen the cortical Off response, the cortical OSR, and the MMN.

Neonatal exposure to an inflammatory cytokine, epidermal growth factor, results in the deficits of mismatch negativity in rats

Perinatal exposure to epidermal growth factor (EGF) induces various cognitive and behavioral abnormalities after maturation in non-human animals, and is used for animal models of schizophrenia. Patients with schizophrenia often display a reduction of mismatch negativity (MMN), which is a stimulus-change specific event-related brain potential. Do the EGF model animals also exhibit the MMN reduction as schizophrenic patients do? This study addressed this question to verify the pathophysiological validity of this model. Neonatal rats received repeated administration of EGF or saline and were grown until adulthood. Employing the odd-ball paradigm of distinct tone pitches, tone-evoked electroencephalogram (EEG) components were recorded from electrodes on the auditory and frontal cortices of awake rats, referencing an electrode on the frontal sinus. The amplitude of the MMN-like potential was significantly reduced in EGF-treated rats compared with saline-injected control rats. The wavelet analysis of the EEG during a near period of tone stimulation revealed that synchronization of EEG activity, especially with beta and gamma bands, was reduced in EGF-treated rats. Results suggest that animals exposed to EGF during a perinatal period serve as a promising neurodevelopmental model of schizophrenia.

Maturation of Speech-Sound ERPs in 5-6-Year-Old Children: A Longitudinal Study

The maturation of 5-6-year-old children's auditory discrimination - indicated by the development of the auditory event-related-potentials (ERPs) - has not been previously studied in longitudinal settings. For the first time, we present here the results based on extensive dataset collected from 75 children. We followed the 5- to 6-year-olds for 20 months and measured their ERPs four times with the same multifeature paradigm with phonemic stimuli. The amplitude of the mismatch negativity (MMN) response increased during this time for vowel, vowel duration and frequency changes. Furthermore, the P3a component started to mature toward adult-like positivity for the vowel, intensity and frequency deviants and the late discriminative negativity (LDN) component decreased with age for vowel and intensity deviants. All the changes in the components seemed to happen during the second follow-up year, when Finnish children are taught letter symbols and other preliminary academic skills before going to school at the age of seven. Therefore, further studies are needed to clarify if these changes in the auditory discrimination are purely age-related or due to increasing linguistic knowledge of the children.

Task-free auditory EEG paradigm for probing multiple levels of speech processing in the brain

While previous studies on language processing highlighted several ERP components in relation to specific stages of sound and speech processing, no study has yet combined them to obtain a comprehensive picture of language abilities in a single session. Here, we propose a novel task-free paradigm aimed at assessing multiple levels of speech processing by combining various speech and nonspeech sounds in an adaptation of a multifeature passive oddball design. We recorded EEG in healthy adult participants, who were presented with these sounds in the absence of sound-directed attention while being engaged in a primary visual task. This produced a range of responses indexing various levels of sound processing and language comprehension: (a) P1-N1 complex, indexing obligatory auditory processing; (b) P3-like dynamics associated with involuntary attention allocation for unusual sounds; (c) enhanced responses for native speech (as opposed to nonnative phonemes) from ∼50 ms from phoneme onset, indicating phonological processing; (d) amplitude advantage for familiar real words as opposed to meaningless pseudowords, indexing automatic lexical access; (e) topographic distribution differences in the cortical activation of action verbs versus concrete nouns, likely linked with the processing of lexical semantics. These multiple indices of speech-sound processing were acquired in a single attention-free setup that does not require any task or subject cooperation; subject to future research, the present protocol may potentially be developed into a useful tool for assessing the status of auditory and linguistic functions in uncooperative or unresponsive participants, including a range of clinical or developmental populations.

The Duration of Auditory Sensory Memory for Vowel Processing: Neurophysiological and Behavioral Measures

Speech perception behavioral research suggests that rates of sensory memory decay are dependent on stimulus properties at more than one level (e.g., acoustic level, phonemic level). The neurophysiology of sensory memory decay rate has rarely been examined in the context of speech processing. In a lexical tone study, we showed that long-term memory representation of lexical tone slows the decay rate of sensory memory for these tones. Here, we tested the hypothesis that long-term memory representation of vowels slows the rate of auditory sensory memory decay in a similar way to that of lexical tone. Event-related potential (ERP) responses were recorded to Mandarin non-words contrasting the vowels /i/ vs. /u/ and /y/ vs. /u/ from first-language (L1) Mandarin and L1 American English participants under short and long interstimulus interval (ISI) conditions (short ISI: an average of 575 ms, long ISI: an average of 2675 ms). Results revealed poorer discrimination of the vowel contrasts for English listeners than Mandarin listeners, but with different patterns for behavioral perception and neural discrimination. As predicted, English listeners showed the poorest discrimination and identification for the vowel contrast /y/ vs. /u/, and poorer performance in the long ISI condition. In contrast to Yu et al. (2017), however, we found no effect of ISI reflected in the neural responses, specifically the mismatch negativity (MMN), P3a and late negativity ERP amplitudes. We did see a language group effect, with Mandarin listeners generally showing larger MMN and English listeners showing larger P3a. The behavioral results revealed that native language experience plays a role in echoic sensory memory trace maintenance, but the failure to find an effect of ISI on the ERP results suggests that vowel and lexical tone memory traces decay at different rates.

Highlights:

We examined the interaction between auditory sensory memory decay and language experience.

We compared MMN, P3a, LN and behavioral responses in short vs. long interstimulus intervals.

We found that different from lexical tone contrast, MMN, P3a, and LN changes to vowel contrasts are not influenced by lengthening the ISI to 2.6 s.

We also found that the English listeners discriminated the non-native vowel contrast with lower accuracy under the long ISI condition.

Task-Irrelevant Novel Sounds have Antithetical Effects on Visual Target Processing in Young and Old Adults

In young adults, primary visual task processing can be either enhanced or disrupted by novel auditory stimuli preceding target events, depending on task demands. Little is known about this phenomenon in older individuals, who, in general, are more susceptible to distraction. In the current study, age-related differences in the electrophysiological effects of task-irrelevant auditory stimuli on visual target processing were examined. Under both low and high primary task loads, the categorization/updating process in response to visual targets preceded by auditory novels, as indexed by the target P3 component, was enhanced in young, but diminished in old adults. In both age groups, the alerting/orienting response to novel auditory stimuli, as measured by the P3a, was smaller under high task load, whereas redirecting attention to the visual task after a novel auditory event, as indexed by the reorienting negativity (RON), tended to be augmented under high task load. Old subjects generated a smaller P3a and RON. We conclude that task irrelevant novel auditory stimuli have the opposite effect on the processing of visual targets in young and old adults. This finding may help explain age-related increases in the disruption of primary task activity by irrelevant, but salient auditory events.

Involuntary Capture and Voluntary Reorienting of Attention Decline in Middle-Aged and Old Participants

The main aim of this study was to examine the effects of aging on event-related brain potentials (ERPs) associated with the automatic detection of unattended infrequent deviant and novel auditory stimuli (Mismatch Negativity, MMN) and with the orienting to these stimuli (P3a component), as well as the effects on ERPs associated with reorienting to relevant visual stimuli (Reorienting Negativity, RON). Participants were divided into three age groups: (1) Young: 21-29 years old; (2) Middle-aged: 51-64 years old; and (3) Old: 65-84 years old. They performed an auditory-visual distraction-attention task in which they were asked to attend to visual stimuli (Go, NoGo) and to ignore auditory stimuli (S: standard, D: deviant, N: novel). Reaction times (RTs) to Go visual stimuli were longer in old and middle-aged than in young participants. In addition, in all three age groups, longer RTs were found when Go visual stimuli were preceded by novel relative to deviant and standard auditory stimuli, indicating a distraction effect provoked by novel stimuli. ERP components were identified in the Novel minus Standard (N-S) and Deviant minus Standard (D-S) difference waveforms. In the N-S condition, MMN latency was significantly longer in middle-aged and old participants than in young participants, indicating a slowing of automatic detection of changes. The following results were observed in both difference waveforms: (1) the P3a component comprised two consecutive phases in all three age groups-an early-P3a (e-P3a) that may reflect the orienting response toward the irrelevant stimulation and a late-P3a (l-P3a) that may be a correlate of subsequent evaluation of the infrequent unexpected novel or deviant stimuli; (2) the e-P3a, l-P3a, and RON latencies were significantly longer in the Middle-aged and Old groups than in the Young group, indicating delay in the orienting response to and the subsequent evaluation of unattended auditory stimuli, and in the reorienting of attention to relevant (Go) visual stimuli, respectively; and (3) a significantly smaller e-P3a amplitude in Middle-aged and Old groups, indicating a deficit in the orienting response to irrelevant novel and deviant auditory stimuli.

Interaction of Musicianship and Aging: A Comparison of Cortical Auditory Evoked Potentials

Objective. The goal of this study was to begin to explore whether the beneficial auditory neural effects of early music training persist throughout life and influence age-related changes in neurophysiological processing of sound. Design. Cortical auditory evoked potentials (CAEPs) elicited by harmonic tone complexes were examined, including P1-N1-P2, mismatch negativity (MMN), and P3a. Study Sample. Data from older adult musicians (n = 8) and nonmusicians (n = 8) (ages 55–70 years) were compared to previous data from young adult musicians (n = 40) and nonmusicians (n = 20) (ages 18–33 years). Results. P1-N1-P2 amplitudes and latencies did not differ between older adult musicians and nonmusicians; however, MMN and P3a latencies for harmonic tone deviances were earlier for older musicians than older nonmusicians. Comparisons of P1-N1-P2, MMN, and P3a components between older and young adult musicians and nonmusicians suggest that P1 and P2 latencies are significantly affected by age, but not musicianship, while MMN and P3a appear to be more sensitive to effects of musicianship than aging. Conclusions. Findings support beneficial influences of musicianship on central auditory function and suggest a positive interaction between aging and musicianship on the auditory neural system.

Paying attention to MMN in schizophrenia

The aim of this review is to explore the phenomenon of reduced mismatch negativity (MMN) in persons with schizophrenia and the possible relationship it has with attention impairments. In doing so we discuss (i) the prediction error account of MMN, (ii) reduced MMN as a faulty predictive processing system in persons with schizophrenia, (iii) the role of these systems in relevance filtering and attentional resource protection, (iv) attentional impairments in persons with schizophrenia, and (v) research that has explored MMN and attention in schizophrenia groups. Our review of the literature suggests that no study has appropriately examined the functional impact of smaller MMN in schizophrenia on the performance of a concurrent attention task. We conclude that future research should explore this notion further in the hope that it might embed MMN findings within outcomes of functional significance to individuals with the illness and those providing treatment. This article is part of a Special Issue entitled SI: Prediction and Attention.

What we expect is not always what we get: evidence for both the direction-of-change and the specific-stimulus hypotheses of auditory attentional capture

Participants were requested to respond to a sequence of visual targets while listening to a well-known lullaby. One of the notes in the lullaby was occasionally exchanged with a pattern deviant. Experiment 1 found that deviants capture attention as a function of the pitch difference between the deviant and the replaced/expected tone. However, when the pitch difference between the expected tone and the deviant tone is held constant, a violation to the direction-of-pitch change across tones can also capture attention (Experiment 2). Moreover, in more complex auditory environments, wherein it is difficult to build a coherent neural model of the sound environment from which expectations are formed, deviations can capture attention but it appears to matter less whether this is a violation from a specific stimulus or a violation of the current direction-of-change (Experiment 3). The results support the expectation violation account of auditory distraction and suggest that there are at least two different expectations that can be violated: One appears to be bound to a specific stimulus and the other would seem to be bound to a more global cross-stimulus rule such as the direction-of-change based on a sequence of preceding sound events. Factors like base-rate probability of tones within the sound environment might become the driving mechanism of attentional capture—rather than violated expectations—in complex sound environments.

Effects of aging and involuntary capture of attention on event-related potentials associated with the processing of and the response to a target stimulus

The main aim of the present study was to assess whether aging modulates the effects of involuntary capture of attention by novel stimuli on performance, and on event-related potentials (ERPs) associated with target processing (N2b and P3b) and subsequent response processes (stimulus-locked Lateralized Readiness Potential -sLRP- and response-locked Lateralized Readiness Potential -rLRP-). An auditory-visual distraction-attention task was performed by 77 healthy participants, divided into three age groups (Young: 21-29, Middle-aged: 51-64, Old: 65-84 years old). Participants were asked to attend to visual stimuli and to ignore auditory stimuli. Aging was associated with slowed reaction times, target stimulus processing in working memory (WM, longer N2b and P3b latencies) and selection and preparation of the motor response (longer sLRP and earlier rLRP onset latencies). In the novel relative to the standard condition we observed, in the three age groups: (1) a distraction effect, reflected in a slowing of reaction times, of stimuli categorization in WM (longer P3b latency), and of motor response selection (longer sLRP onset latency); (2) a facilitation effect on response preparation (later rLRP onset latency), and (3) an increase in arousal (larger amplitudes of all ERPs evaluated, except for N2b amplitude in the Old group). A distraction effect on the stimulus evaluation processes (longer N2b latency) were also observed, but only in middle-aged and old participants, indicating that the attentional capture slows the stimulus evaluation in WM from early ages (from 50 years onwards, without differences between middle-age and older adults), but not in young adults.

What determines auditory distraction? On the roles of local auditory changes and expectation violations

Both the acoustic variability of a distractor sequence and the degree to which it violates expectations are important determinants of auditory distraction. In four experiments we examined the relative contribution of local auditory changes on the one hand and expectation violations on the other hand in the disruption of serial recall by irrelevant sound. We present evidence for a greater disruption by auditory sequences ending in unexpected steady state distractor repetitions compared to auditory sequences with expected changing state endings even though the former contained fewer local changes. This effect was demonstrated with piano melodies (Experiment 1) and speech distractors (Experiment 2). Furthermore, it was replicated when the expectation violation occurred after the encoding of the target items (Experiment 3), indicating that the items' maintenance in short-term memory was disrupted by attentional capture and not their encoding. This seems to be primarily due to the violation of a model of the specific auditory distractor sequences because the effect vanishes and even reverses when the experiment provides no opportunity to build up a specific neural model about the distractor sequence (Experiment 4). Nevertheless, the violation of abstract long-term knowledge about auditory regularities seems to cause a small and transient capture effect: Disruption decreased markedly over the course of the experiments indicating that participants habituated to the unexpected distractor repetitions across trials. The overall pattern of results adds to the growing literature that the degree to which auditory distractors violate situation-specific expectations is a more important determinant of auditory distraction than the degree to which a distractor sequence contains local auditory changes.

Processing of complex distracting sounds in school-aged children and adults: evidence from EEG and MEG data

When a perceiver performs a task, rarely occurring sounds often have a distracting effect on task performance. The neural mismatch responses in event-related potentials to such distracting stimuli depend on age. Adults commonly show a negative response, whereas in children a positive as well as a negative mismatch response has been reported. Using electro- and magnetoencephalography (EEG/MEG), here we investigated the developmental changes of distraction processing in school-aged children (9–10 years) and adults. Participants took part in an auditory-visual distraction paradigm comprising a visuo-spatial primary task and task-irrelevant environmental sounds distracting from this task. Behaviorally, distractors delayed reaction times (RTs) in the primary task in both age groups, and this delay was of similar magnitude in both groups. The neurophysiological data revealed an early as well as a late mismatch response elicited by distracting stimuli in both age groups. Together with previous research, this indicates that deviance detection is accomplished in a hierarchical manner in the auditory system. Both mismatch responses were localized to auditory cortex areas. All mismatch responses were generally delayed in children, suggesting that not all neurophysiological aspects of deviance processing are mature in school-aged children. Furthermore, the P3a, reflecting involuntary attention capture, was present in both age groups in the EEG with comparable amplitudes and at similar latencies, but with a different topographical distribution. This suggests that involuntary attention shifts toward complex distractors operate comparably in school-aged children and adults, yet undergoing generator maturation.

Preparation interval and cue utilization in the prevention of distraction

Maintaining a selective attention set allows us to efficiently perform sensory tasks despite the multitude of concurrent sensory stimuli. Unpredictably occurring, rare events nonetheless capture our attention, that is, we get distracted. The present study investigated the efficiency of control over distraction as a function of preparation time available before a forthcoming distracter. A random sequence of short and long tones (100 or 200 ms with 50-50 % probability) was presented. Independently from tone duration, occasionally (13.3 % of the time), the pitch of a tone was changed. Such rare pitch variants (distracters) usually lead to delayed and less precise discrimination responses, and trigger a characteristic series of event-related potentials (ERPs) reflecting the stages of distraction-related processing: starting with negative ERPs signaling the sensory registration of the distracter; a P3a-usually interpreted as a reflection of involuntary attention change and finally the so-called reorienting negativity signaling the restoration of the task-optimal attention set. In separate conditions, 663 or 346 ms before each tone (long or short cue-tone interval), a visual cue was presented, which signaled whether the forthcoming tone was a distracter (rare pitch variant), with 80 % validity. As reflected by reduced reaction time delays and P3a amplitudes, valid cues led to the prevention of distraction, but only in the long cue-tone interval condition. The analyses of the cue-related P3b and contingent negative variation showed that participants made more effort to utilize cue information to prevent distraction in the long cue-tone than in the short cue-tone interval condition.

The role of auditory transient and deviance processing in distraction of task performance: a combined behavioral and event-related brain potential study

Distraction of goal-oriented performance by a sudden change in the auditory environment is an everyday life experience. Different types of changes can be distracting, including a sudden onset of a transient sound and a slight deviation of otherwise regular auditory background stimulation. With regard to deviance detection, it is assumed that slight changes in a continuous sequence of auditory stimuli are detected by a predictive coding mechanisms and it has been demonstrated that this mechanism is capable of distracting ongoing task performance. In contrast, it is open whether transient detection-which does not rely on predictive coding mechanisms-can trigger behavioral distraction, too. In the present study, the effect of rare auditory changes on visual task performance is tested in an auditory-visual cross-modal distraction paradigm. The rare changes are either embedded within a continuous standard stimulation (triggering deviance detection) or are presented within an otherwise silent situation (triggering transient detection). In the event-related brain potentials, deviants elicited the mismatch negativity (MMN) while transients elicited an enhanced N1 component, mirroring pre-attentive change detection in both conditions but on the basis of different neuro-cognitive processes. These sensory components are followed by attention related ERP components including the P3a and the reorienting negativity (RON). This demonstrates that both types of changes trigger switches of attention. Finally, distraction of task performance is observable, too, but the impact of deviants is higher compared to transients. These findings suggest different routes of distraction allowing for the automatic processing of a wide range of potentially relevant changes in the environment as a pre-requisite for adaptive behavior.

The dissociation between the P3a event-related potential and behavioral distraction

Unexpected novel sounds can capture our attention and impair performance. Recent behavioral research revealed that only novel sounds that provided target-related (but not task-related) information impaired performance. This poses the question of the automaticity of novelty processing and its expression at the behavioral level. In an auditory-visual oddball paradigm, the informational content of sounds regarding the time and probability of target occurrence was varied. Independent from the informational content, novel, and deviant sounds elicited the P3a, an ERP-component related to novelty processing. In contrast, impaired performance was only observed if target-related information was provided. Results indicate that distractor sounds are automatically evaluated as potentially significant, but that the consequences for behavior depend on further processes such as the processing of the given information.

Expectations modulate the magnitude of attentional capture by auditory events

What determines the magnitude of attentional capture by deviant sound events? We combined the cross-modal oddball distraction paradigm with sequence learning to address this question. Participants responded to visual targets, each preceded by tones that formed a repetitive cross-trial standard sequence. In Experiment 1, with the standard tone sequence …-660-440-660-880-… Hz, either the 440 Hz or the 880 Hz standard was occasionally replaced by one of two deviant tones (220 Hz and 1100 Hz), that either differed slightly (by 220 Hz) or markedly (by 660 Hz) from the replaced standard. In Experiment 2, with the standard tone sequence …-220-660-440-660-880-660-1100-… Hz, the 440 Hz and the 880 Hz standard was occasionally replaced by either a 220 Hz or a 1100 Hz pattern deviant. In both experiments, a high-pitch deviant was more captivating when it replaced a low-pitch standard, and a low-pitch deviant was more captivating when it replaced a high-pitch standard. These results indicate that the magnitude of attentional capture by deviant sound events depends on the discrepancy between the deviant event and the expected event, not on perceived local change.

Automatic processing of rare versus novel auditory stimuli reveal different mechanisms of auditory change detection

Automatic detection of rare stimuli or changes in an auditory stimulation can distract ongoing task processing by attracting attention away from task relevant information. Typically, the effectiveness of auditory change detection is tested by rare and unpredictable deviations (compared with an otherwise regular auditory presentation) or by rare environmental sounds. The present study demonstrates that both types of stimuli are capable of triggering automatic orientation of attention and that rare environmental sounds are more effective than deviations in distraction of attention. This finding suggests different mechanisms underlying the detection of auditory change. Moreover, novelty as constituted by unique environmental sounds did not add to the effectiveness of automatic change detection, involuntary control of attention, and distraction.

Auditory processing in autism spectrum disorder: a review

For individuals with autism spectrum disorder or 'ASD' the ability to accurately process and interpret auditory information is often difficult. Here we review behavioural, neurophysiological and imaging literature pertaining to this field with the aim of providing a comprehensive account of auditory processing in ASD, and thus an effective tool to aid further research. Literature was sourced from peer-reviewed journals published over the last two decades which best represent research conducted in these areas. Findings show substantial evidence for atypical processing of auditory information in ASD at behavioural and neural levels. Abnormalities are diverse, ranging from atypical perception of various low-level perceptual features (i.e. pitch, loudness) to processing of more complex auditory information such as prosody. Trends across studies suggest auditory processing impairments in ASD are most likely to present during processing of complex auditory information and are more severe for speech than for non-speech stimuli. The interpretation of these findings with respect to various cognitive accounts of ASD is discussed and suggestions offered for further research.

Preventing distraction: assessing stimulus-specific and general effects of the predictive cueing of deviant auditory events

Rare irregular sounds (deviants) embedded into a regular sound sequence have large potential to draw attention to themselves (distraction). It has been previously shown that distraction, as manifested by behavioral response delay, and the P3a and reorienting negativity (RON) event-related potentials, could be reduced when the forthcoming deviant was signaled by visual cues preceding the sounds. In the present study, we investigated the type of information used in the prevention of distraction by manipulating the information content of the visual cues preceding the sounds. Cues could signal the specific variant of the forthcoming deviant, or they could just signal that the next tone was a deviant. We found that stimulus-specific cue information was used in reducing distraction. The results also suggest that early P3a and RON index processes related to the specific deviating stimulus feature, whereas late P3a reflects a general distraction-related process.

Electrophysiological evidence of nicotine's distracter-filtering properties in non-smokers

Nicotine-enhanced attentional functions are purported to underlie improvements in behavioral performance in cognitive tasks but it is unclear as to whether these effects involve selective attention or attentional control under conditions of distraction. Behavioral and event-related potential measures were used to examine the effects of nicotine on distractibility in 21 non-smokers who were instructed to ignore task-irrelevant auditory stimuli while they performed a visual discrimination task. In a randomized, double-blind, placebo-controlled cross-over design, nicotine gum (6 mg) shortened overall reaction times but failed to prevent increased response slowing and errors caused by deviant sounds. Relative to placebo, nicotine did not modulate the early pre-attentive detection of deviants as reflected in the mismatch negativity but it attenuated the amplitude of the deviant-elicited P3a, an event-related potential component indexing the involuntary shifting of attention. Nicotine also enhanced attentional re-focusing back on to task-relevant stimuli following distraction as evidenced by an increased amplitude of the re-orienting negativity. These findings and the behavioral-electrophysiological dissociation seen with nicotine are discussed in relation to theories of attention and smoking motivation.

The modulation of auditory novelty processing by working memory load in school age children and adults: a combined behavioral and event-related potential study

BACKGROUND

We investigated the processing of task-irrelevant and unexpected novel sounds and its modulation by working-memory load in children aged 9-10 and in adults. Environmental sounds (novels) were embedded amongst frequently presented standard sounds in an auditory-visual distraction paradigm. Each sound was followed by a visual target. In two conditions, participants evaluated the position of a visual stimulus (0-back, low load) or compared the position of the current stimulus with the one two trials before (2-back, high load). Processing of novel sounds were measured with reaction times, hit rates and the auditory event-related brain potentials (ERPs) Mismatch Negativity (MMN), P3a, Reorienting Negativity (RON) and visual P3b.

RESULTS

In both memory load conditions novels impaired task performance in adults whereas they improved performance in children. Auditory ERPs reflect age-related differences in the time-window of the MMN as children showed a positive ERP deflection to novels whereas adults lack an MMN. The attention switch towards the task irrelevant novel (reflected by P3a) was comparable between the age groups. Adults showed more efficient reallocation of attention (reflected by RON) under load condition than children. Finally, the P3b elicited by the visual target stimuli was reduced in both age groups when the preceding sound was a novel.

CONCLUSION

Our results give new insights in the development of novelty processing as they (1) reveal that task-irrelevant novel sounds can result in contrary effects on the performance in a visual primary task in children and adults, (2) show a positive ERP deflection to novels rather than an MMN in children, and (3) reveal effects of auditory novels on visual target processing.

Non-linear laws of echoic memory and auditory change detection in humans

BACKGROUND

The detection of any abrupt change in the environment is important to survival. Since memory of preceding sensory conditions is necessary for detecting changes, such a change-detection system relates closely to the memory system. Here we used an auditory change-related N1 subcomponent (change-N1) of event-related brain potentials to investigate cortical mechanisms underlying change detection and echoic memory.

RESULTS

Change-N1 was elicited by a simple paradigm with two tones, a standard followed by a deviant, while subjects watched a silent movie. The amplitude of change-N1 elicited by a fixed sound pressure deviance (70 dB vs. 75 dB) was negatively correlated with the logarithm of the interval between the standard sound and deviant sound (1, 10, 100, or 1000 ms), while positively correlated with the logarithm of the duration of the standard sound (25, 100, 500, or 1000 ms). The amplitude of change-N1 elicited by a deviance in sound pressure, sound frequency, and sound location was correlated with the logarithm of the magnitude of physical differences between the standard and deviant sounds.

CONCLUSIONS

The present findings suggest that temporal representation of echoic memory is non-linear and Weber-Fechner law holds for the automatic cortical response to sound changes within a suprathreshold range. Since the present results show that the behavior of echoic memory can be understood through change-N1, change-N1 would be a useful tool to investigate memory systems.

To switch or not to switch: brain potential indices of attentional control after task-relevant and task-irrelevant changes of stimulus features

Attention is controlled by the interplay of sensory input and top-down processes. We compared attentional control processes during task switching and reorientation after distraction. The primary task was to discriminate laterally and centrally presented tones; these stimuli were composed of a frequent standard or an infrequent deviant pitch. In the distraction condition, pitch was irrelevant and could be ignored. In the switch condition, pitch changes were relevant: whenever a deviant tone was presented, participants had to discriminate its pitch and not its direction. The task in standard trials remained unchanged. In both conditions, deviants elicited mismatch negativity (MMN), P3a, P3b, and reorienting negativity (RON). We, therefore, suggest that distraction and switching are triggered by the same system of attentional control. In addition, remarkable differences were observable between the two conditions: In the switch condition the MMN was followed by a more pronounced N2b and P3a. The differences between these components support the idea that in the distraction condition, a switch of attention is only initiated but not completely performed.

On the functional significance of Novelty-P3: facilitation by unexpected novel sounds

The unexpected occurrence of a change in the auditory context has been shown to result in distraction due to a momentary attention shift. These unexpected sounds elicit the Novelty-P3 (NP3) response which has been proposed as an electrophysiological index of distractibility, and used as such in the evaluation of several clinical populations. However, unexpected sounds also result in facilitation under certain conditions. Here, we investigate the electrophysiological concomitants of novel sounds in a task in which these sounds facilitate visual task performance. Novel sounds elicited NP3 and resulted in an enhancement of the visual P300 response to subsequent visual targets. This result clearly argues against the use of NP3 as an index of distractibility and asks for a reformulation of the functional significance of this response. We suggest that the NP3 is a complex signal that comprises alerting, orienting and executive control processes triggered by the unexpected stimulus.

Modulation of auditory evoked responses to spectral and temporal changes by behavioral discrimination training

Background

Due to auditory experience, musicians have better auditory expertise than non-musicians. An increased neocortical activity during auditory oddball stimulation was observed in different studies for musicians and for non-musicians after discrimination training. This suggests a modification of synaptic strength among simultaneously active neurons due to the training. We used amplitude-modulated tones (AM) presented in an oddball sequence and manipulated their carrier or modulation frequencies. We investigated non-musicians in order to see if behavioral discrimination training could modify the neocortical activity generated by change detection of AM tone attributes (carrier or modulation frequency). Cortical evoked responses like N1 and mismatch negativity (MMN) triggered by sound changes were recorded by a whole head magnetoencephalographic system (MEG). We investigated (i) how the auditory cortex reacts to pitch difference (in carrier frequency) and changes in temporal features (modulation frequency) of AM tones and (ii) how discrimination training modulates the neuronal activity reflecting the transient auditory responses generated in the auditory cortex.

Results

The results showed that, additionally to an improvement of the behavioral discrimination performance, discrimination training of carrier frequency changes significantly modulates the MMN and N1 response amplitudes after the training. This process was accompanied by an attention switch to the deviant stimulus after the training procedure identified by the occurrence of a P3a component. In contrast, the training in discrimination of modulation frequency was not sufficient to improve the behavioral discrimination performance and to alternate the cortical response (MMN) to the modulation frequency change. The N1 amplitude, however, showed significant increase after and one week after the training. Similar to the training in carrier frequency discrimination, a long lasting involuntary attention to the deviant stimulus was observed.

Conclusion

We found that discrimination training differentially modulates the cortical responses to pitch changes and to envelope fluctuation changes of AM tones. This suggests that discrimination between AM tones requires additional neuronal mechanisms compared to discrimination process between pure tones. After the training, the subjects demonstrated an involuntary attention switch to the deviant stimulus (represented by the P3a-component in the MEG) even though attention was not prerequisite.

Involuntary Orienting of Attention to Nociceptive Events: Neural and Behavioral Signatures

Pain can involuntarily capture attention and disrupt pain-unrelated cognitive activities. The brain mechanisms of these effects were explored by laser- and visual-evoked potentials. Consecutive nociceptive laser stimuli and visual stimuli were delivered in pairs. Subjects were instructed to ignore nociceptive stimuli while performing a task on visual targets. Because involuntary attention is particularly sensitive to novelty, in some trials (17%), unexpected laser stimuli were delivered on a different hand area (location-deviant) relative to the more frequent standard laser stimuli. Compared with frequent standard laser stimuli, deviant stimuli enhanced all nociceptive-evoked brain potentials (laser N1, N2, P2a, P2b). Deviant laser stimuli also decreased the amplitude of late latency–evoked responses (visual N2-P3) to the subsequent visual targets and delayed reaction times to them. The data confirm that nociceptive processing competes with pain-unrelated cognitive activities for attentional resources and that concomitant nociceptive events affect behavior by depressing attention allocation to ongoing cognitive processing. The laser-evoked potential magnitude reflected the engagement of attention to the novel nociceptive stimuli. We conclude that the laser-evoked potentials index the activity of a neural system involved in the detection of novel salient stimuli in order to focus attention and prioritize action to potentially damaging dangers.

The cognitive control of distraction by novelty in children aged 7-8 and adults

The study focused on the development of cognitive control of distraction. Novel sounds were interspersed in a sequence of a constant environmental sound, while subjects were engaged in a task not related to novelty. In both children (7-8 years) and adults, unpredictable novel sounds caused prolonged reaction times (RT), the P3a and the Reorienting Negativity (RON) components of the event-related potential, indicating distraction and reorienting of attention. With predictable novels, RT prolongation and RON-amplitude were reduced in both groups, whereas P3a-amplitude reduction was confined to adults. Thus, although children reveal some indication for control of distraction, they do not yet achieve the level of adults. This differential pattern of the development of RT prolongation, P3a, and RON across age groups indicates different maturation of processes involved in the control of distraction and suggests partly independent underlying processes.