Syllable Processing Research Articles

Asymmetric Function of Theta and Gamma Activity in Syllable Processing: An Intra-Cortical Study

Low-gamma (25–45 Hz) and theta (4–8 Hz) oscillations are proposed to underpin the integration of phonemic and syllabic information, respectively. How these two scales of analysis split functions across hemispheres is unclear. We analyzed cortical responses from an epileptic patient with a rare bilateral electrode implantation (stereotactic EEG) in primary (A1/BA41 and A2/BA42) and association auditory cortices (BA22). Using time-frequency analyses, we confirmed the dominance of a 5–6 Hz theta activity in right and of a low-gamma (25–45 Hz) activity in left primary auditory cortices (A1/A2), during both resting state and syllable processing. We further detected high-theta (7–8 Hz) resting activity in left primary, but also associative auditory regions. In left BA22, its phase correlated with high-gamma induced power. Such a hierarchical relationship across theta and gamma frequency bands (theta/gamma phase-amplitude coupling) could index the process by which the neural code shifts from stimulus feature- to phonological-encoding, and is associated with the transition from evoked to induced power responses. These data suggest that theta and gamma activity in right and left auditory cortices bear different functions. They support a scheme where slow parsing of the acoustic information dominates in right hemisphere at a syllabic (5–6 Hz) rate, and left auditory cortex exhibits a more complex cascade of oscillations, reflecting the possible extraction of transient acoustic cues at a fast (~25–45 Hz) rate, subsequently integrated at a slower, e.g., syllabic one. Slow oscillations could functionally participate to speech processing by structuring gamma activity in left BA22, where abstract percepts emerge.

Enhanced Passive and Active Processing of Syllables in Musician Children

The aim of this study was to examine the influence of musical expertise in 9-year-old children on passive (as reflected by MMN) and active (as reflected by discrimination accuracy) processing of speech sounds. Musician and nonmusician children were presented with a sequence of syllables that included standards and deviants in vowel frequency, vowel duration, and VOT. Both the passive and the active processing of duration and VOT deviants were enhanced in musician compared with nonmusician children. Moreover, although no effect was found on the passive processing of frequency, active frequency discrimination was enhanced in musician children. These findings are discussed in terms of common processing of acoustic features in music and speech and of positive transfer of training from music to the more abstract phonological representations of speech units (syllables).

Effects of diet on early stage cortical perception and discrimination of syllables differing in voice-onset time: A longitudinal ERP study in 3 and 6 month old infants

The influence of diet on cortical processing of syllables was examined at 3 and 6 months in 239 infants who were breastfed or fed milk or soy-based formula. Event-related potentials to syllables differing in voice-onset-time were recorded from placements overlying brain areas specialized for language processing. P1 component amplitude and latency measures indicated that at both ages infants in all groups could extract and discriminate categorical information from syllables. Between-syllable amplitude differences—present across groups—were generally greater for SF infants. Responses peaked earlier over left hemisphere speech-perception than speech-production areas. Encoding was faster in BF than formula-fed infants. The results show that in preverbal infants: (1) discrimination of phonetic information occurs in early stages of cortical processing; (2) areas overlying brain regions of speech perception are activated earlier than those involved in speech production; and (3) these processes are differentially modulated by infant diet and environmental factors.

Songbirds possess the spontaneous ability to discriminate syntactic rules

Whether the computational systems in language perception involve specific abilities in humans is debated. The vocalizations of songbirds share many features with human speech, but whether songbirds possess a similar computational ability to process auditory information as humans is unknown. We analyzed their spontaneous discrimination of auditory stimuli and found that the Bengalese finch (Lonchura striata var. domestica) can use the syntactical information processing of syllables to discriminate songs). These finches were also able to acquire artificial grammatical rules from synthesized syllable strings and to discriminate novel auditory information according to them. We found that a specific brain region was involved in such discrimination and that this ability was acquired postnatally through the encounter with various conspecific songs. Our results indicate that passerine songbirds spontaneously acquire the ability to process hierarchical structures, an ability that was previously supposed to be specific to humans.

Cortical Spatio-temporal Dynamics Underlying Phonological Target Detection in Humans

Selective processing of task-relevant stimuli is critical for goal-directed behavior. We used electrocorticography to assess the spatio-temporal dynamics of cortical activation during a simple phonological target detection task, in which subjects press a button when a prespecified target syllable sound is heard. Simultaneous surface potential recordings during this task revealed a highly ordered temporal progression of high gamma (HG, 70-200 Hz) activity across the lateral hemisphere in less than 1 sec. The sequence demonstrated concurrent regional sensory processing of speech syllables in the posterior superior temporal gyrus (STG) and speech motor cortex, and then transitioned to sequential task-dependent processing from prefrontal cortex (PFC), to the final motor response in the hand sensorimotor cortex. STG activation was modestly enhanced for target over nontarget sounds, supporting a selective gain mechanism in early sensory processing, whereas PFC was entirely selective to targets, supporting its role in guiding response behavior. These results reveal that target detection is not a single cognitive event, but rather a process of progressive target selectivity that involves large-scale rapid parallel and serial processing in sensory, cognitive, and motor structures to support goal-directed human behavior.

Procesamiento de sílabas que son prefijos

The present article reviews experimental data obtained with behavioral methods (reaction times) and event-related potentials on the processing of syllables and prefixes. Syllables are used in Spanish as a mechanism of word pre-activation in the lexical memory and require inhibition of lexical selection. In contrast, prefixes, as a morphological unit — although they are also syllables — produce a facilitating effect on word meaning, this process being free of inhibitory processes. We conclude that the two units employ dissimilar routes and activate a different time-course process. Hypotheses relating these basic discoveries in adults with the child population are tentatively proposed, since these units — syllables and morphemes — constitute basic prelexical units in the acquisition of reading abilities.

Enhanced passive and active processing of syllables in musician children

Event Abstract Back to Event Enhanced passive and active processing of syllables in musician children Julie Chobert1*, Céline Marie2, Clément François1, Daniele Schön1 and Mireille Besson1 1 INCM-CNRS, France 2 McMaster University, Canada The aim of this study was to examine the influence of musical expertise in 9 year-old children on passive (as reflected by the Mismatch Negativity, MMN) and active (as reflected by discrimination accuracy) processing of speech sounds. Children on their way towards musicianship had 4 years of musical training, on average and nonmusicians had no other musical training than mandatory at school. Musician and nonmusician children were presented with a sequence of syllables that included standards (syllable “Ba”) and deviants in vowel duration, vowel frequency and Voice Onset Time (VOT), either close to or far from the standard (Small and Large deviants). Following the MMN experiment, during which children watched a silent movie, the same sequence of syllables was presented again and children were asked to press a button each time they heard a deviant (active processing). Both the passive and the active processing of duration deviants were enhanced in musician compared to non-musician children. Moreover, only musician children showed larger MMN amplitude and shorter Reaction Times (RTs) to Large than to Small VOT deviants. Nonmusicians showed no differences between Large and Small VOT deviant either during passive or during active listening. Finally, no effect of musical expertise was found on the passive processing of frequency, whereas frequency discrimination was enhanced in musician children. These findings are discussed in terms of common processing of acoustic features in music and speech and of positive transfer of training from music to the more abstract phonological representations of speech units (syllables). Keywords: Language, Music Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Neural Bases of Language Citation: Chobert J, Marie C, François C, Schön D and Besson M (2011). Enhanced passive and active processing of syllables in musician children. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00202 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 21 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Miss. Julie Chobert, INCM-CNRS, Marseille, France, julie.chobert@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Julie Chobert Céline Marie Clément François Daniele Schön Mireille Besson Google Julie Chobert Céline Marie Clément François Daniele Schön Mireille Besson Google Scholar Julie Chobert Céline Marie Clément François Daniele Schön Mireille Besson PubMed Julie Chobert Céline Marie Clément François Daniele Schön Mireille Besson Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Domain specificity of speech processing: a combined MEG-EEG study

Event Abstract Back to Event Domain specificity of speech processing: a combined MEG-EEG study Soila Kuuluvainen1*, Päivi Nevalainen2, Alexander Sorokin3, Kaisu Krohn1, Maria Mittag1, Eino Partanen1, Vesa Putkinen1, Miia Seppänen1, Seppo Kähkönen2 and Teija Kujala1 1 Cognitive Brain Research Unit, Institute of Behavioral Sciences, University of Helsinki, Finland 2 BioMag Laboratory, Hospital District of Helsinki and Uusimaa, HUSLAB, Helsinki University Central Hospital, Finland 3 Laboratory of Neurophysiology, Mental Health Research Centre, Russian Academy of Medical Sciences, Russia We investigated speech-sound domain specificity and lateralization of sound processing by examining the cortical discrimination profile for speech features and their no speech counterparts in healthy adults. MMNs were recorded to five syllable deviants (vowel, consonant, frequency, duration, and intensity) and their acoustically matching no speech counterparts with a combined MEG-EEG device, using a multi-feature MMN paradigm. The dipole moments of the MMNm for speech sound changes were larger than for no speech counterparts. This was mostly due to vowel changes eliciting larger dipoles than their counterparts. Enhancement was also found for duration and frequency MMNms in the speech condition when compared to the no speech condition. Further, the intensity MMNm was larger in the right than left hemisphere. A separate analysis for each hemisphere, however, suggested hemispheric differences in processing speech vs. no speech sounds. Speech sounds elicited larger MMNm dipoles for vowel, consonant and duration changes than no speech sounds in the left hemisphere, whereas no feature-specific effects were found in the right hemisphere. The EEG results were mainly consistent with the MEG results, with larger MMN amplitudes for vowel and frequency changes in the speech than no speech condition but larger duration MMN amplitude in the no speech than speech condition. Both MEG and EEG results support the theory of domain-specific speech perception for vowel and consonant category changes. For changes in syllable duration and frequency, both of which are important semantic and syntactic cues in the Finnish language, the MEG results suggest enhanced temporal processing of syllables compared to their no speech counterparts. Keywords: EEG, Language, MEG Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Neural Bases of Language Citation: Kuuluvainen S, Nevalainen P, Sorokin A, Krohn K, Mittag M, Partanen E, Putkinen V, Seppänen M, Kähkönen S and Kujala T (2011). Domain specificity of speech processing: a combined MEG-EEG study. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00192 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Soila Kuuluvainen, Cognitive Brain Research Unit, Institute of Behavioral Sciences, University of Helsinki, Helsinki, Finland, soila.kuuluvainen@helsinki.fi Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Soila Kuuluvainen Päivi Nevalainen Alexander Sorokin Kaisu Krohn Maria Mittag Eino Partanen Vesa Putkinen Miia Seppänen Seppo Kähkönen Teija Kujala Google Soila Kuuluvainen Päivi Nevalainen Alexander Sorokin Kaisu Krohn Maria Mittag Eino Partanen Vesa Putkinen Miia Seppänen Seppo Kähkönen Teija Kujala Google Scholar Soila Kuuluvainen Päivi Nevalainen Alexander Sorokin Kaisu Krohn Maria Mittag Eino Partanen Vesa Putkinen Miia Seppänen Seppo Kähkönen Teija Kujala PubMed Soila Kuuluvainen Päivi Nevalainen Alexander Sorokin Kaisu Krohn Maria Mittag Eino Partanen Vesa Putkinen Miia Seppänen Seppo Kähkönen Teija Kujala Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Laterality effects for musical structure processing: A dichotic listening study.

Our study investigated hemispheric lateralization for musical structure processing using a dichotic listening paradigm with music and speech. Eight chord sequences and 8 spoken syllable sequences were simultaneously presented, each to 1 ear. For the musical sequences, the final chord was expected (i.e., tonic) or less expected (i.e., subdominant). In addition to tonal function, which was task irrelevant, we manipulated the final syllable and the final timbre of the sequences for the experimental task: Participants were asked to identify the final syllable (/di/, /du/) or the timbre of the final chord (Timbre A or B). Our experiment revealed a left-ear advantage for the tonal function effect on spoken syllable identification. For syllables presented to the right ear, identification was faster when the final chord of the musical sequence was a tonic chord rather than a subdominant chord (i.e., musical sequences presented to the left ear). The present finding extends the effect of musical structure previously observed for sung and visual syllable processing to spoken syllable processing. It further suggests a right-hemispheric specialization for the processing of musical structures in healthy listeners, as previously reported for split-brain patients (Tramo & Bharucha, 1991).

Timing is everything: Neural response dynamics during syllable processing and its relation to higher-order cognition in schizophrenia and healthy comparison subjects

Successful linguistic processing requires efficient encoding of successively-occurring auditory input in a time-constrained manner, especially under noisy conditions. In this study we examined the early neural response dynamics to rapidly-presented successive syllables in schizophrenia participants and healthy comparison subjects, and investigated the effects of noise on these responses. We used magnetoencephalography (MEG) to reveal the time-course of stimulus-locked activity over bilateral auditory cortices during discrimination of syllable pairs that differed either in voice onset time (VOT) or place of articulation (POA), in the presence or absence of noise. We also examined the association of these early neural response patterns to higher-order cognitive functions. The M100 response, arising from auditory cortex and its immediate environs, showed less attenuation to the second syllable in patients with schizophrenia than healthy comparison subjects during VOT-based discrimination in noise. M100 response amplitudes were similar between groups for the first syllable during all three discrimination conditions, and for the second syllable during VOT-based discrimination in quiet and POA-based discrimination in noise. Across subjects, the lack of M100 attenuation to the second syllable during VOT-based discrimination in noise was associated with poorer task accuracy, lower education and IQ, and lower scores on measures of Verbal Learning and Memory and Global Cognition. Because the neural response to the first syllable was not significantly different between groups, nor was a schizophrenia-related difference obtained in all discrimination tasks, early linguistic processing dysfunction in schizophrenia does not appear to be due to general sensory input problems. Rather, data suggest that faulty temporal integration occurs during successive syllable processing when the signal-to-noise ratio is low. Further, the neural mechanism by which the second syllable is suppressed during noise-challenged VOT discrimination appears to be important for higher-order cognition and provides a promising target for neuroscience-guided cognitive training approaches to schizophrenia.

Temporal Order Processing of Syllables in the Left Parietal Lobe

Speech processing requires the temporal parsing of syllable order. Individuals suffering from posterior left hemisphere brain injury often exhibit temporal processing deficits as well as language deficits. Although the right posterior inferior parietal lobe has been implicated in temporal order judgments (TOJs) of visual information, there is limited evidence to support the role of the left inferior parietal lobe (IPL) in processing syllable order. The purpose of this study was to examine whether the left inferior parietal lobe is recruited during temporal order judgments of speech stimuli. Functional magnetic resonance imaging data were collected on 14 normal participants while they completed the following forced-choice tasks: (1) syllable order of multisyllabic pseudowords, (2) syllable identification of single syllables, and (3) gender identification of both multisyllabic and monosyllabic speech stimuli. Results revealed increased neural recruitment in the left inferior parietal lobe when participants made judgments about syllable order compared with both syllable identification and gender identification. These findings suggest that the left inferior parietal lobe plays an important role in processing syllable order and support the hypothesized role of this region as an interface between auditory speech and the articulatory code. Furthermore, a breakdown in this interface may explain some components of the speech deficits observed after posterior damage to the left hemisphere.

Syllable frequency effects in visual word recognition: Developmental approach in French children

This study investigates the syllable's role in the normal reading acquisition of French children at three grade levels (1st, 3rd, and 5th), using a modified version of Colé, Magnan, and Grainger's (1999) paradigm. We focused on the effects of syllable frequency and word frequency. The results suggest that from the first to third years of reading instruction, children process high-frequency syllables as syllable units while processing low-frequency syllables as phoneme units. In fifth graders, syllable-based processing is extended to both high and low syllable frequencies, primarily due to CVC structures with high-frequency syllables. Lexical frequency does not significantly influence syllable processing. These findings reveal that the syllable is an early prelexical unit modulated initially by syllable frequency, and subsequently by grapheme-to-phoneme correspondences. High-frequency syllables did not produce inhibitory effects. Consequently, results are compatible with Levelt and Wheeldon's (1994) mental syllabary hypothesis. Implications for specific reading training and syllable based remediation are discussed.

Syllabic Effects in Italian Lexical Access

Two cross-modal priming experiments tested whether lexical access is constrained by syllabic structure in Italian. Results extend the available Italian data on the processing of stressed syllables showing that syllabic information restricts the set of candidates to those structurally consistent with the intended word (Experiment 1). Lexical access, however, takes place as soon as possible and it is not delayed till the incoming input corresponds to the first syllable of the word. And, the initial activated set includes candidates whose syllabic structure does not match the intended word (Experiment 2). The present data challenge the early hypothesis that in Romance languages syllables are the units for lexical access during spoken word recognition. The implications of the results for our understanding of the role of syllabic information in language processing are discussed.

ERP measures of syllable processing in 1 year olds: infant diet‐ and gender‐related differences

Language skills are generally better in females than males, but the basis for these differences has not been determined. To investigate whether variations in infant diet contribute to these differences, cortical responses to the syllable /pa/ (ERPs;124 sites) were examined in healthy 12‐month old, full‐term infants enrolled in a longitudinal study of infant diet on development (Beginnings study). Infants were breastfed exclusively through 4 months and predominantly through 12 months (BF: n = 66, 33 males) or fed commercially produced formulas [milk‐based (MF: n = 65, 37 males) or soy‐based (SF: n = 61, 31 males)] exclusively from at least age 2 through 4 months, and remained on the same formula type through 12 months. ERPs were recorded in awake infants and analyzed using ANOVAs with post‐hoc t‐tests. Amplitude data for central and temporal cortical areas are reported for responses reflecting sensory registration (P150) and later language feature processing (P370). Group by gender interactions (p < .05) in both brain regions for the P370 reflected higher amplitudes for males than females in BF and MF groups, but not in the SF group. Across groups P370 amplitude was similar for males, but greater in SF females relative to females in other groups (p < .02). Whether these diet‐ and gender‐related differences in syllable processing relate to later language development will be determined as this longitudinal study progresses. (Supported by USDA CRIS 6251‐51000‐002‐03S)

Roles of consonant status and sonority in printed syllable processing: Evidence from illusory conjunction and audio-visual recognition tasks in French adults.

Notre etude visait a etudier le role du codage phonologique en lecture silencieuse chez des adultes francais. Nous avons particulierement etudie le profil de sonorite, les regles phonotactiques ainsi que la structure syllabique aux frontieres syllabiques grâce a une tâche de reconnaissance audio-visuelle et au paradigme des conjonctions illusoires (Prinzmetal, Treiman & Rho, 1986). Nous avons evalue si les adultes experts avaient recours aux syllabes. Nous souhaitions egalement observer si le codage phonologique etait sensible a des facteurs linguistiques tels que le statut de la consonne pivot et au profil de sonorite. Les resultats obtenus dans les deux experiences ont montre que les adultes s’appuyaient sur les syllabes. Cependant, le recours aux syllabes etait influence et contraint par la phonotactique. En effet, les adultes se sont montres sensibles aux profils de sonorite pour determiner les frontieres syllabiques. Ainsi, les profils intervocaliques respectant un cycle de sonorite optimal (i.e., coda liquide-attaque plosive) ont ete preferes aux autres profils de sonorite. Ces donnees s’accordent avec les theories linguistiques selon lesquelles le contact optimal entre deux syllabe repose sur une coda plus sonore que la consonne subsequente en position d’attaque (e.g., Clements, 1990).

Early infant diet and ERP correlates of speech stimuli discrimination in 9 month old infants

Processing and discrimination of speech stimuli were examined during the initial period of weaning in infants enrolled in a longitudinal study of infant diet and development (the Beginnings Study). Event‐related potential measures (ERP; 128 sites) were used to compare the processing of speech stimuli in healthy 9‐month old, full‐term infants who were exclusively breast‐fed (BF, n = 60) with those fed milk‐ (MF, n = 59) or soy‐based formula (SF, n = 61) since 2 months of age. ERPs were recorded in awake infants to two syllables (/pa/ and /ba/; randomized 80%:20% occurrence) and analyzed using ANOVA procedures with post‐hoc t‐tests. Data are reported for responses during the first 600 ms post‐stimulus in central and anterior temporal cortical areas. Significant (p < .05) between‐syllable differences in amplitude (/ba/ > /pa/) and latency (/ba/ < /pa/) were observed in all groups and generally similar across groups. However, greater between‐syllable amplitude differences for the late N450 component in BF and MF relative to SF infants suggests more extensive language‐related processing in BF and MF groups at this time. Whether these response patterns reflect transient diet‐related variations in syllable processing or represent differences that influence later language development may be clarified as this longitudinal study progresses. (Supported by USDA CRIS 6251‐51000‐002‐03S)

The Influence of Infant Diet on Early Developmental Changes in Processing Human Voice Speech Stimuli: ERP Variations in Breast and Milk Formula-Fed Infants at 3 and 6 Months After Birth

The purpose of this investigation was to determine if processing of language stimuli during the first half year of life in breast-fed infants differs from that of formula-fed infants. This question was addressed by examining the brain event-related potentials of healthy infants receiving breast milk (n = 15) or milk-based formula (n = 18) recorded in response to consonant vowel syllables presented in an oddball paradigm. The same infants were studied when they were 3-months and 6-months-old. The two groups were comparable on several measures relating to biological and home environment variables previously reported to influence development, including gestation period, birth weight, mother's IQ, and family socioeconomic status, and did not differ in weight or mental or motor development at the times of the visits. In general, ERP response features previously documented in studies of syllable processing in 3–6-month-old infants were observed in this study, including positive components at ∼ 190 msec (P1), ∼ 370 msec (P2), and ∼ 600 msec (P600), and negative components at ∼ 250 msec (N250), ∼ 450 msec (N450), and a late, negative going slow wave between 655 and 995 msec (LSW). For both groups there were instances where specific components were either poorly defined, e.g., P1 and N250 to the infrequent syllable at 3 months, N450 and P600 to this syllable at both ages, or not present in many infants, e.g., the P600 to the frequent syllable at 6 months. These variations appeared to be related to individual differences in development or paradigm-related features, i.e., ISI and frequency of syllable occurrence. Developmental variations (changes from 3 to 6 months) common to both feeding groups included latency decreases for P1, decreased P2 amplitude, and increased amplitudes for N250 and LSW components. Within this framework, group differences were detected in areas involving the development of response components, the development of processing capabilities, and syllable discrimination. In all cases, these effects related to components following initial stimulus registration, i.e., to the processing of sound content rather than sound acoustic features. The pattern of these differences suggests advantages for BF infants in the development and processing of language stimuli during the first 6 months of life.

Auditory evoked fields differentially encode speech features: an MEG investigation of the P50m and N100m time courses during syllable processing

The functional organization of speech sound processing in the human brain and its unfolding over time are still not well understood. While the N100/N100m is a comparatively well-studied, and quite late, component of the auditory evoked field elicited by speech, earlier processes such as those reflected in the P50m remain to be resolved. Using magnetoencephalography, the present study follows up on previous reports of N100m-centred spatiotemporal encoding of phonological features and coarticulatory processes in the auditory cortex during consonant-vowel syllable perception. Our results indicate that the time course and response strength of the P50m and N100m components of evoked magnetic fields are differentially influenced by mutually exclusive place-of-articulation features of a syllable's stop consonant and vowel segments. Topographical differences in P50m generators were driven by place contrasts between consonants in syllables, with spatial gradients orthogonal to the ones previously reported for N100m. Peak latency results replicated previous findings for the N100m and revealed a reverse pattern for the earlier P50m (shorter latencies depending on the presence of a back vowel [o]). Our findings allow attribution of a role in basic feature extraction to the comparatively early P50m time window. Moreover, the observations substantiate the assumption that the N100m response reflects a more abstract phonological representational stage during speech perception.

Processing of Syllables in Production and Recognition Tasks

Empirical evidence for a functional role of syllables in visual word processing is abundant, however it remains rather heterogeneous. The present study aims to further specify the role of syllables and the cognitive accessibility of syllabic information in word processing. The first experiment compared performance across naming and lexical decision tasks by manipulating the number of syllables in words and non-words. Results showed a syllable number effect in both the naming task and the lexical decision task. The second experiment introduced a stimulus set consisting of isolated syllabic and non-syllabic trigrams. Syllable frequency was manipulated in a naming and in a decision task requiring participants to decide on the syllabic status of letter strings. Results showed faster responses for syllables than for non-syllables in both tasks. Syllable frequency effects were observed in the decision task. In summary, the results from these manipulations of different types of syllable information confirm an important role of syllabic units in both recognition and production.

Effects of classical conditioning on identification and cortical processing of speech syllables

The present study was designed to examine effects of learned motivational significance on processing of speech syllables in adults using a classical conditioning paradigm. Aversive white noise (unconditioned stimulus) was paired with two exemplars of /ba/ (conditioned stimulus, CS+) occurring near the category boundary of a 10-item /ba/-da/ continuum. Two corresponding /da/ syllables served as the CS- and indicated absence of white noise. High-density electroencephalogram (EEG) was recorded while participants passively listened to the stimuli. Prior to the EEG session and after intermittent conditioning, participants were asked to identify the syllables in a categorical perception task. Analysis of time-locked electrocortical data revealed amplitude modulations of the N2 (248-312 ms) component as a function of acquired stimulus properties (CS+ versus CS-). Over right hemisphere regions, negativity was specifically enhanced for the CS+ during intermittent conditioning. During extinction, this conditioning effect was paralleled by findings in the time-frequency domain, showing greater oscillatory activity in the gamma-band (25-40 Hz) range, 80-120 ms following onset of the CS+ compared with CS-. A similar pattern emerged in a later time segment of 400-600 ms (30-45 Hz). Aversive conditioning was not reflected in superior categorical perception performance. Our data indicate that electrocortical correlates of speech syllable perception are susceptible to changes induced by contingencies. Physiological differences were not manifest in behavioral advantage for a specific stimulus, i.e., the CS+, however. We conclude that training speech categorization by merely enhancing motivational relevance is not effective for conveying behavioral improvement.