Attention effects on auditory scene analysis in children

Auditory scene analysis begins in infancy, making it possible for the baby to distinguish its mother's voice from other noises in the environment. Despite the importance of this process for human behavior, the question of how perceptual sound organization develops during childhood is not well understood. The current study investigated the role of attention for perceiving sound streams in a group of school-aged children and young adults. We behaviorally determined the frequency separation at which a set of sounds was detected as one integrated or two separated streams and compared these measures with passively and actively obtained electrophysiological indices (mismatch negativity (MMN) and P3b) of the same sounds. In adults, there was a high degree of concordance between passive and active electrophysiological indices of stream segregation that matched with perception. In contrast, there was a large disparity in children. Active electrophysiological indices of streaming were concordant with behavioral measures of perception, whereas passive indices were not. In addition, children required larger frequency separations to perceive two streams compared to adults. Our results suggest that differences in stream segregation between children and adults reflect an under-development of basic auditory processing mechanisms, and indicate a developmental role of attention for shaping physiological responses that optimize processes engaged during passive audition.     

Conflict adaptation and sequential trial effects: support for the conflict monitoring theory

The purpose of this study was to investigate the cognitive control process of conflict adaptation and the recruitment of cognitive control across sequential trials-termed higher-order trial effects-using the N2 and P3 components of the scalp-recorded event-related potential (ERP). High-density ERPs were obtained from 181 healthy individuals (93 female, 88 male) during a modified Eriksen flanker task. Behavioral measures (i.e., error rates, reaction times [RTs]) and N2 and P3 amplitudes showed reliable conflict adaptation (i.e., previous-trial congruencies influenced current-trial measures). Higher-order trial effects were quantified across multiple sequential presentations of congruent or incongruent trials (e.g., four consecutive incongruent trials). For higher-order trial effects, P3 amplitudes and RTs reliably decreased across both congruent and incongruent trials. Consistent with the conflict monitoring theory, N2 amplitudes decreased across incongruent trials and increased across congruent trials. N2 amplitudes were positively correlated with incongruent-trial RTs; no significant correlations were found for P3 amplitudes and RTs. Effects remained when stimulus-response repetitions were removed. Results indicate that RTs and ERP measures are sensitive to modulations of cognitive control associated with conflict across multiple congruent and incongruent trials. Implications for the conflict monitoring theory of cognitive control are discussed.     

Electrophysiological analysis of cognitive slowing in subjects with mitochondrial encephalomyopathy.

Mitochondrial encephalomyopathies (MEs) are multisystemic inherited disorders affecting tissues with high energy requirement such as the muscle, retina and central nervous system. Progressive external ophthalmoplegia and myopathy are the most common features in adults, and cognitive impairment is rare. In many neurodegenerative disorders, ERPs have been effectively performed to record cognitive slowing on tasks with different amount of information. To analyze the evidence for possible cognitive slowing, a standard auditory oddball paradigm with a button-press response was applied. Participants were 11 non-demented patients affected by mitochondrial encephalomyopathy and 14 age-matched normal controls. This hypothesis was tested using two tasks of different difficulty (pure tone vs. phonetic stimuli). Reaction time (RT), performance (P) and event-related potentials (ERPs) were measured. RT and P were not significantly different between the groups. Patients showed significantly increased N2 latency and reduced P3 amplitude on both tasks. No difference was found in pure tone and phonetic task conditions. Results were interpreted as electrophysiological signs of cognitive slowing--particularly in relation to stimulus evaluation--irrespective of sensory problems, response selection and cognitive load. These findings suggest that in ME patients, there may be a possible dysfunction of neural mechanisms underlying cognitive events and ERP generation.     

The visual magnocellular pathway in Chinese-speaking children with developmental dyslexia

Previous research into the cognitive processes involved in reading Chinese and developmental dyslexia in Chinese, revealed that the single most important factor appears to be orthographic processing skills rather than phonological skills. Also some studies have indicated that even in alphabetic languages some dyslexic individuals reveal deficits in orthographic processing skills, which are linked to a deficit in the visual magnocellular pathway. The current study therefore employed a visual psychophysical experiment together with visual and auditory event-related potential (ERP) experiments eliciting mismatch negativity (MMN) to investigate the link between visual magnocellular functional abnormalities and developmental dyslexia in Chinese. The performance levels of Chinese children with developmental dyslexia (DD) from the behavioural and electrophysiological experiments were compared to those of the chronological age-matched (CA) children and those of the reading level matched (RL) younger children. Both the behavioural and electrophysiological results suggest that the orthographic processing skills were compromised in the Chinese developmental dyslexics, which in turn is linked to a deficit in the visual magnocellular system.     

The effects of stress and statistical cues on continuous speech segmentation: an event-related brain potential study

The study of the processes involved in speech segmentation has gained special relevance in recent years by trying to establish what type of information listeners use to segment the speech signal into words. An event-related brain potential experiment was conducted in order to understand how two of these cues (statistical and stress cues) interact. The experiment consisted of the presentation of artificial speech streams in which words were marked either by statistical cues alone, or by a combination of statistical and stress cues. As a baseline, comparison streams were also created with the same syllables but organized in random order. Results showed an N400 component that marks the on-line segmentation of speech into words, and an increased positivity (P2 component) for languages that include both types of cues. Possible implications of these results for the process of speech segmentation are discussed.     

Attention orienting dysfunction with preserved automatic auditory change detection in migraine

ObjectiveTo investigate automatic event-related potentials (ERPs) to an auditory change in migraine patients.MethodsAuditory ERPs were recorded in 22 female patients suffering from menstrually-related migraine and in 20 age-matched control subjects, in three sessions: in the middle of the menstrual cycle, before and during menses. In each session, 200 trains of tone-bursts each including two duration deviants were presented in a passive listening condition.ResultsIn all sessions, duration deviance elicited a mismatch negativity (MMN) showing no difference between the two groups. However, migraine patients showed an increased N1 orienting component to all incoming stimuli and a prolonged N2b to deviance. They also presented a different modulation of P3a amplitude along the menstrual cycle, which tended to normalise during migraine attacks. None of the studied ERP components showed a default of habituation.ConclusionsThis passive paradigm highlighted increased automatic attention orienting to auditory changes but normal auditory sensory processing in migraineurs.SignificanceOur observations suggest normal auditory processing up to attention triggering but enhanced activation of attention-related frontal networks in migraineurs.     

Association between dopamine D4 receptor (DRD4) gene polymorphisms and novelty-elicited auditory event-related potentials in preschool children

We investigated associations of the exon III repeat and the -521 C/T polymorphisms of the DRD4 gene with novelty-elicited auditory ERP components and behavioral resistance to distraction in 57 healthy, typically developing 6-year-old children. Dopamine-related gene polymorphisms have previously been linked to processes directing focused attention. We did not find associations between the 7-repeat allele or the T.7 haplotype and the early ERP responses suggesting that DRD4 polymorphisms did not affect the detection of novelty. However, the same polymorphisms affected the late negative components (LN1 and LN2). Late negativities elicited by deviant and novel sounds have been regarded as reflecting reorientation after distraction or additional processing of new information. Children carrying the T.7 haplotype had significantly smaller LN1 and LN2 amplitudes. The presence of the T.7 haplotype also significantly enhanced behavioral resistance to distraction. We suggest that less distraction in T.7 carriers led to less reorienting activity (reflected by the LN components). We also speculate that activation of less sensitive and fewer D4 receptors (as with the T.7 haplotype) is less effective in modulating GABAergic inhibitory signaling, which in turn is reflected in smaller LN amplitudes.     

Attachment affects social information processing: Specific electrophysiological effects of maternal stimuli

Attachment is critical to each individual. It affects the cognitive-affective processing of social information. The present study examines how attachment affects the processing of social information, specifically maternal information. We assessed the behavioral and electrophysiological responses to maternal information (compared to non-specific others) in a Go/No-go Association Task (GNAT) with 22 participants. The results illustrated that attachment affected maternal information processing during three sequential stages of information processing. First, attachment affected visual perception, reflected by enhanced P100 and N170 elicited by maternal information as compared to others information. Second, compared to others, mother obtained more attentional resources, reflected by faster behavioral response to maternal information and larger P200 and P300. Finally, mother was evaluated positively, reflected by shorter P300 latency in a mother + good condition as compared to a mother + bad condition. These findings indicated that the processing of attachment-relevant information is neurologically differentiated from other types of social information from an early stage of perceptual processing to late high-level processing.     

The effects of induced state negative affect on performance monitoring processes

Previous research suggests that performance-monitoring processes are related to personality traits; relationships with affective states, however, remain unclear. The purpose of this study was to replicate and extend previous findings that induced state negative affect alters electrophysiological reflections of performance monitoring. High-density event-related potentials (ERPs) were obtained from 69 healthy individuals (41 female, 28 male) who completed an Eriksen flanker task and received either encouraging or derogatory feedback based on mean reaction times (RTs) for 30-trial sub-blocks. Affective state, behavioral measures (i.e. error rates, RTs) and ERP measures [i.e. error-related negativity (ERN), post-error positivity (Pe) and N2] were assessed. Reaction times did not differ between feedback groups. Participants who received derogatory feedback committed more errors over time. Despite changes in affect, no significant group differences were demonstrated for behavioral or ERP measures of performance monitoring. Increases in vigilance were associated with more negative N2 amplitudes; no other changes in affective state were associated with changes in ERP measures. Results are consistent with findings suggesting performance-monitoring processes are only slightly affected by changes in affective state and fail to replicate previous studies suggesting the ERN is related to state changes in affect-supporting the possibility of the ERN as an endophenotype.     

Electrophysiological indices of automatic and controlled auditory information processing in first-episode, recent-onset and chronic schizophrenia.

BACKGROUND: Deficits in amplitudes of auditory event-related potentials (ERP) indexing preattentive, automatic (mismatch negativity, MMN) and controlled, attention-dependent (N2, P3) auditory information processing have been well described in chronic schizophrenia. Normal MMN, but deficient N2 and P3 have been reported in first-episode patients. No study has investigated these ERPs concurrently in first-episode patients; thus, reported differences in MMN, N2 and P3 generation may reflect differences in patient samples rather than genuine differences in abnormal generation of these ERPs. METHODS: We recorded MMN, N2 and P3 in 26 first-episode patients, 25 recent-onset patients within 1.5 to 5 years after first admission, 25 chronic patients and 39 healthy controls. RESULTS: Recent-onset and chronic, but not first-episode patients showed reduced MMN. However, among first-episode patients those with low premorbid educational achievement demonstrated significantly reduced MMN. All patient groups showed pronounced N2 deficits and, to a variable extent, abnormalities in P3 generation. CONCLUSIONS: Abnormalities in N2 and P3 generation appear to reflect premorbid neuropathology, whereas MMN deficits may index both ongoing disease processes associated with illness progression as well as premorbid neurocognitive impairment. ERPs may provide tools to assess static and progressive neuropathology in schizophrenia. These findings need confirmation in longitudinal studies.     

The relevance of the functional 5-HT1A receptor polymorphism for attention and working memory processes during mental rotation of characters

Numerous lines of research indicate that attentional processes, working memory and saccadic processes are highly interrelated. In the current study, we examine the relation between these processes with respect to their cognitive-neurophysiological and neurobiological background by means of event-related potentials (ERPs) in a sample of N = 72 healthy probands characterized for the functional serotonin receptor 1 A (5-HT1A) C(−1019)G polymorphism.The results support a close interrelation between working memory, attentional and saccadic processes. Yet, these processes are differentially modulated by the 5-HT1A C(−1019)G polymorphism. The 5-HT1A C(−1019)G polymorphism primarily affects attentional processing, whereas processes related to the mental rotation of an object are independent of 5-HT1A genetic variation. It is shown that an increasing number of −1019 G alleles leads to a differential reduction of the N1 above the left and right hemisphere and hence bottom-up attentional processing. In the way increasing numbers of −1019 G alleles lead to a reduction of attentional processes, saccadic activity increases as a similar function of the number of −1019 G alleles. This increase in activity occurs parallel in time to the process of mental rotation. It is hypothesized that decreased attentional processes, dependent on different 5-HT1A C(−1019)G genotypes, may cause parietal networks to increase saccadic activity in order to perform mental rotation.     

An event-related examination of neural activity during social interactions

Social exclusion is known to cause alterations in neural activity and perceptions of social distress. However, previous research is largely limited to examining social interactions as a unitary phenomenon without investigating adjustments in neural and attentional processes that occur during social interactions. To address this limitation, we examined neural activity on a trial-by-trial basis during different social interactions. Our results show conflict monitoring neural alarm activation, indexed by the N2, in response to specific exclusionary events; even during interactions that are inclusionary overall and in the absence of self-reported feelings of social pain. Furthermore, we show enhanced attentional activation to exclusionary events, indexed by the P3b, during exclusionary, compared with inclusionary, interactions, and this P3b activation was associated with self-reported social distress following prolonged social exclusion. Finally, both the N2 and P3b showed larger amplitudes in the earlier stages of exclusion compared with later stages, suggesting heightened early sensitivity for both components. Together, these findings provide novel insights into the dynamic neural and perceptual processes of exclusion that exist during social interactions and the relationship between discrete events within interactions and the more general contexts of the social interactions.     

Neural dynamics of inflectional and derivational morphology processing in the human brain

We investigated neural distinctions between inflectional and derivational morphology and their interaction with lexical frequency using the mismatch negativity (MMN), an established neurophysiological index of experience-dependent linguistic memory traces and automatic syntactic processing. We presented our electroencephalography (EEG) study participants with derived and inflected words of variable lexical frequencies against their monomorphemic base forms in a passive oddball paradigm, along with acoustically matched pseudowords. Sensor space and distributed source modelling results showed that at 100–150 msec after the suffix onset, derived words elicited larger responses than inflected words. Furthermore, real derived words showed advantage over pseudo-derivations and frequent derivations elicited larger activation than less frequent ones. This pattern of results is fully in line with previous research that explained lexical MMN enhancement by an activation of strongly connected word-specific long-term memory circuits, and thus suggests stronger lexicalisation for frequently used complex words. At the same time, a strikingly different pattern was found for inflectional forms: higher response amplitude for pseudo-inflections than for real inflected words, with no clear frequency effects. This is fully in line with previous MMN results on combinatorial processing of (morpho)syntactic stimuli: higher response to ungrammatical morpheme strings than grammatical ones, which does not depend on the string's surface frequency. This pattern suggests that, for inflectional forms, combinatorial processing route dominates over whole-form storage and access. In sum, our results suggest that derivations are more likely to form unitary representations than inflections which are likely to be processed combinatorially, and imply at least partially distinct brain mechanisms for the processing and representation of these two types of morphology. These dynamic mechanisms, underpinned by perisylvian networks, are activated rapidly, at 100–150 msec after the information arrives at the input, and in a largely automatic fashion, possibly providing neural basis for the first-pass morphological processing of spoken words.     

Newborn brain event-related potentials revealing atypical processing of sound frequency and the subsequent association with later literacy skills in children with familial dyslexia

The role played by an auditory-processing deficit in dyslexia has been debated for several decades. In a longitudinal study using brain event-related potentials (ERPs) we investigated 1) whether dyslexic children with familial risk background would show atypical pitch processing from birth and 2) how these newborn ERPs later relate to these same children’s pre-reading cognitive skills and literacy outcomes. Auditory ERPs were measured at birth for tones varying in pitch and presented in an oddball paradigm (1100 Hz, 12%, and 1000 Hz, 88%). The brain responses of the typically reading control group children (TRC group, N = 25) showed clear differentiation between the frequencies, while those of the group of reading disability with familial risk (RDFR, 8 children) and the group of typical readers with familial risk (TRFR, 14 children) did not differentiate between the tones. The ERPs of the latter two groups differed from those of the TRC group. However, the two risk groups also showed a differential hemispheric ERP pattern. Furthermore, newborn ERPs reflecting passive change detection were associated with phonological skills and letter knowledge prior to school age and with phoneme duration perception, reading speed (RS) and spelling accuracy in the 2nd grade of school. The early obligatory response was associated with more general pre-school language skills, as well as with RS and reading accuracy (RA). Results suggest that a proportion of dyslexic readers with familial risk background are affected by atypical auditory processing. This is already present at birth and also relates to pre-reading phonological processing and speech perception. These early differences in auditory processing could later affect phonological representations and reading development. However, atypical auditory processing is unlikely to suffice as a sole explanation for dyslexia but rather as one risk factor, dependent on the genetic profile of the child.     

Processing acoustic change and novelty in newborn infants

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

Electrophysiological correlates of the retention of tones differing in timbre in auditory short-term memory

We examined the electrophysiological correlates of retention in auditory short-term memory (ASTM) for sequences of one, two, or three tones differing in timbre but having the same pitch. We focused on event-related potentials (ERPs) during the retention interval and revealed a sustained fronto-central ERP component (most likely a sustained anterior negativity; SAN) that became more negative as memory load increased. Our results are consistent with recent ERP studies on the retention of pitch and suggest that the SAN reflects brain activity mediating the low-level retention of basic acoustic features in ASTM. The present work shows that the retention of timbre shares common features with the retention of pitch, hence supporting the notion that the retention of basic sensory features is an active process that recruits modality-specific brain areas.     

Auditory event-related potentials at preschool age in children born very preterm

ObjectiveTo assess auditory event-related potentials at preschool age in children born very preterm (VP, 27.4 ± 1.9 gestational weeks, n = 70) with a high risk of cognitive dysfunction.MethodsWe used an oddball paradigm consisting of a standard tone randomly replaced by one of three infrequent deviants (differing in frequency, sound direction or duration).ResultsThe P1 and N2 latencies were inversely correlated to age (50–63 months) both in VP (r = −0.451, p < 0.001, and r = −0.305, p = 0.01, respectively) and term born controls (TC; n = 15). VP children had smaller P1 than near-term (n = 12) or TC (1.70 ± 0.17 μV vs 2.68 ± 0.41 and 2.92 ± 0.43, respectively; p < 0.05). Mismatch negativity response did not differ between groups.ConclusionsOur data suggest a fast maturation of P1 and N2 responses with fast decrease in P1 and N2 latencies around the age of 5 years. Mismatch negativity response does not seem to be a robust measure for defining abnormalities in VP children.SignificanceIn ERP studies in preschool children, even small, non-significant group differences in age at recording should be corrected for. Very preterm born children at preschool age have aERP patterns as earlier described in full-term born children with cognitive deficits.     

The Potential for New Understandings of Normal and Abnormal Cognition by Integration of Neuroimaging and Behavioral Data: Not an Exercise in Carrying Coals to Newcastle

Discovering the means to prevent and cure schizophrenia is a vision that motivates many scientists. But in order to achieve this goal, we need to understand its neurobiological basis. The emergent metadiscipline of cognitive neuroscience fields an impressive array of tools that can be marshaled towards achieving this goal, including powerful new methods of imaging the brain (both structural and functional) as well as assessments of perceptual and cognitive capacities based on psychophysical procedures, experimental tasks and models developed by cognitive science. We believe that the integration of data from this array of tools offers the greatest possibilities and potential for advancing understanding of the neural basis of not only normal cognition but also the cognitive impairments that are fundamental to schizophrenia. Since sufficient expertise in the application of these tools and methods rarely reside in a single individual, or even a single laboratory, collaboration is a key element in this endeavor. Here, we review some of the products of our integrative efforts in collaboration with our colleagues on the East Coast of Australia and Pacific Rim. This research focuses on the neural basis of executive function deficits and impairments in early auditory processing in patients using various combinations of performance indices (from perceptual and cognitive paradigms), ERPs, fMRI and sMRI. In each case, integration of two or more sources of information provides more information than any one source alone by revealing new insights into structure-function relationships. Furthermore, the addition of other imaging methodologies (such as DTI) and approaches (such as computational models of cognition) offers new horizons in human brain imaging research and in understanding human behavior.

Different modalities of painful somatosensory stimulations affect anticipatory cortical processes: a high-resolution EEG study

Pain sensation is characterized by multiple features that allow to differentiate pricking, burning, aching, stinging, and electrical shock. These features are sub-served by neural pathways that might give flexibility and selectivity to the cerebral anticipatory processes. In this line, the present high-resolution electroencephalography (EEG) study tested the hypothesis that the anticipatory cortical processes are stronger for painful thermal (biologically relevant) than electrical ("artificial") stimuli with similar intensity. EEG data (128 electrodes) were recorded in normal subjects during the expectancy of painful electrical or laser stimuli (visual omitted stimulus paradigm; interval between two painful stimuli: 16s), delivered over the median nerve region of the right arm (nonpainful stimuli as controls). After each stimulus, the subject reported the perceived stimulus intensity. Surface Laplacian estimation of the EEG data spatially enhanced the anticipatory stimulus-preceding negativity (SPN), which reflects motivational relevance of the stimulus. Subjects perceived no difference in the intensity of the electrical versus laser stimuli in both painful and nonpainful conditions. However, the anticipatory SPN appeared over large scalp regions before painful laser but not electrical stimulation. The same was true for the nonpainful stimulations. The present results suggest that the motivational anticipatory cortical processes are induced by nonpainful and painful biologically/ecologically relevant laser stimuli rather than by "artificial" electrical stimuli with similar intensity.     

ERP correlates of processing native and non-native language word stress in infants with different language outcomes

The early acquisition of native language prosody is assumed to ease infants' language development. In a longitudinal setting we investigated whether the early processing of native and non-native language word stress patterns is associated with children's subsequent language skills. ERP data of 71 four- and five-month-old infants were retrospectively grouped according to children's verbal performance in a language test at 2.5 years. Children who displayed age-adequate expressive language skills later in development showed both an early and a late negative mismatch response (MMR) when processing the native language stress pattern as deviant in a passive oddball design. Children with poor language skills later in development did not show these negativities. Both groups displayed an infant-specific positive MMR to the non-native language deviant. This positivity was enhanced and prolonged in children who showed poor language skills later in development as compared to children who showed normal language skills. The results indicate that variability in expressive language development has precursors in infants' ERP correlates of word stress processing.