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ABSTRACT: There has been general consensus that initial word learning during early infancy is a slow and time-consuming process that requires very frequent exposure, whereas later in development, infants are able to quickly learn a novel word for a novel meaning. From the perspective of memory maturation, this shift in behavioral development might represent a shift from slow procedural to fast declarative memory formation. Alternatively, it might be caused by the maturation of specific brain structures within the declarative memory system that may support lexical mapping from the very first. Here, we used the neurophysiological method of ERPs to watch the brain activity of 6-month-old infants, when repeatedly presented with object-word pairs in a cross-modal learning paradigm. We report first evidence that infants as young as 6 months are able to associate objects and words after only very few exposures. A memory test 1 day later showed that infants did not fully forget this newly acquired knowledge, although the ERP effects indicated it to be less stable than immediately after encoding. The combined results suggest that already at 6 months the encoding process of word learning is based on fast declarative memory formation, but limitations in the consolidation of declarative memory diminish the long lasting effect in lexical-semantic memory at that age.
Journal of Cognitive Neuroscience 03/2011; 23(11):3228-40. · 5.18 Impact Factor
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ABSTRACT: The relation between the maturation of brain mechanisms responsible for the N400 elicitation in the event-related brain potential (ERP) and the development of behavioral language skills was investigated in 12-month-old infants. ERPs to words presented in a picture-word priming paradigm were analyzed according to the infants' production and comprehension skills as rated by their parents. Infants with high early word production displayed an N400 semantic priming effect already at 12 months. Infants with low early word production did not show this effect, not even for those words that parents rated to be comprehended by their child. The results suggest that the very early functioning of the neural mechanisms underlying N400 generation is related to the infants' state of behavioral language development. The possible functional relation of the N400 neural mechanisms and the infant's word learning ability is discussed.
Brain and Language 09/2009; 114(2):66-71. · 3.12 Impact Factor
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ABSTRACT: 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.
Cortex 12/2008; 45(5):662-76. · 6.08 Impact Factor
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ABSTRACT: Between 12 and 14 months infants switch from slow to fast word learning mode. The neural processes involved in this development are largely unknown. This study explored the brain activity related to the fast learning of object-word mappings in 14-month-old infants. After four repetitions of eight object-word pairs, two priming effects known from earlier infant event-related potential studies were observed: word form priming indexed by the fronto-lateral negativity in the 200-500 ms range and semantic priming indexed by the parietal N400. These neurophysiological correlates suggest that infants have learned object-word mappings by four presentations. In a test phase applied at least 1 day later, the N400 differentiated between trained congruous and incongruous pairings, which indicates that this newly established referential knowledge has been consolidated in memory.
Neuroreport 11/2008; 19(18):1757-61. · 1.66 Impact Factor
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ABSTRACT: Language is the most important faculty that distinguishes humans from other animals. Infants learn their native language fast and effortlessly during the first years of life, as a function of the linguistic input in their environment. Behavioral studies reported the discrimination of melodic contours [1] and stress patterns [2, 3] in 1-4-month-olds. Behavioral [4, 5] and brain measures [6-8] have shown language-independent discrimination of phonetic contrasts at that age. Language-specific discrimination, however, has been reported for phonetic contrasts only for 6-12-month-olds [9-12]. Here we demonstrate language-specific discrimination of stress patterns in 4-month-old German and French infants by using electrophysiological brain measures. We compare the processing of disyllabic words differing in their rhythmic structure, mimicking German words being stressed on the first syllable, e.g., pápa/daddy[13], and French ones being stressed on the second syllable, e.g., papá/daddy. Event-related brain potentials reveal that experience with German and French differentially affects the brain responses of 4-month-old infants, with each language group displaying a processing advantage for the rhythmic structure typical in its native language. These data indicate language-specific neural representations of word forms in the infant brain as early as 4 months of age.
Current Biology 08/2007; 17(14):1208-11. · 9.65 Impact Factor
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ABSTRACT: Recent developmental research on word processing has shown that mechanisms of lexical priming are already present in 12-month-olds whereas mechanisms of semantic integration indexed by the N400 mature a few months later. In a longitudinal setting we investigated whether the occurrence of an N400 at 19 months is associated with the children's language skills later on. To this end children were retrospectively grouped according to their verbal performance in a language test at 30 months. Children with later age-adequate expressive language skills already displayed an N400 at 19 months. In contrast, children with later poor expressive language skills who have an enhanced risk for the development of specific language impairment (SLI) did not show an early N400. The results imply that children who have deficits in their expressive language at the age of 30 months are already impaired in their semantic development about one year earlier.
Psychophysiology 02/2006; 43(1):1-12. · 3.29 Impact Factor
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ABSTRACT: During their first year of life, infants not only acquire probabilistic knowledge about the phonetic, prosodic, and phonotactic organization of their native language, but also begin to establish first lexical-semantic representations. The present study investigated the sensitivity to phonotactic regularities and its impact on semantic processing in 1-year-olds. We applied the method of event-related brain potentials to 12- and 19-month-old children and to an adult control group. While looking at pictures of known objects, subjects listened to spoken nonsense words that were phonotactically legal (pseudowords) or had phonotactically illegal word onsets (nonwords), or to real words that were either congruous or incongruous to the picture contents. In 19-month-olds and in adults, incongruous words and pseudowords, but not nonwords, elicited an N400 known to ref lect mechanisms of semantic integration. For congruous words, the N400 was attenuated by semantic priming. In contrast, 12-month-olds did not show an N400 difference, neither between pseudo- and nonwords nor between incongruous and congruous words. Both 1-year-old groups and adults additionally displayed a lexical priming effect for congruous words, that is, a negativity starting around 100 msec after words onset. One-year-olds, moreover, displayed a phonotactic familiarity effect, that is, a widely distributed negativity starting around 250 msec in 19-month-olds but occurring later in 12-month-olds. The results imply that both lexical priming and phonotactic familiarity already affect the processing of acoustic stimuli in children at 12 months of age. In 19-month-olds, adult-like mechanisms of semantic integration are present in response to phonotactically legal, but not to phonotactically illegal, nonsense words, indicating that children at this age treat pseudowords, but not nonwords, as potential word candidates.
Journal of Cognitive Neuroscience 12/2005; 17(11):1785-802. · 5.18 Impact Factor
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ABSTRACT: The present study used the N400, an electrophysiological correlate of semantic processing, to investigate 19- and 24-month-old children's ability to integrate the meaning of words in a sentential context. Children listened passively to semantically appropriate sentences and to sentences in which the object noun violates the selection restriction of the verb. The event-related potentials of both age groups revealed an N400 on inappropriate object nouns. This indicates that the children are able to semantically integrate words into sentence contexts. Furthermore, the result implies that selection restrictions are part of the children's first verb representations.
Neuroreport 12/2005; 16(16):1801-4. · 1.66 Impact Factor
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ABSTRACT: Event-related brain potential (ERP) studies of sentence processing in adults have shown that phrase-structure violations are associated with two ERP components: an early left anterior negativity (ELAN) and a late, centro-parietal positivity (P600). Although the ELAN reflects highly automatic first-pass sentence parsing, the P600 has been interpreted to reflect later, more controlled processes. The present ERP study investigates the processing of phrase-structure violations in children below three years of age. Both children (mean age of 2.8 years) and adults passively listened to short active sentences that were either correct or syntactically incorrect. Adults displayed an ELAN that was followed by a P600 to the syntactic violation. Children also demonstrated a biphasic ERP pattern consisting of an early left hemispheric negativity and a late positivity. Both components, however, started later and persisted longer than those observed in adults. The left lateralization of the children's negativity suggests that this component can be interpreted as a child-specific precursor to the ELAN observed in adults. The appearance of the early negativity indicates that the neural mechanisms of syntactic parsing are present, in principle, during early language development.
Journal of Cognitive Neuroscience 11/2005; 17(10):1667-78. · 5.18 Impact Factor
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ABSTRACT: The study at hand investigates prosodic abilities of infants as early predictors of Specific Language Impairment (SLI), which is commonly diagnosed at a later age. The study is based on the hypothesis that the prosodic abilities of infants at risk for SLI are less elaborated than those of controls due to less efficient processing of the relevant acoustic cues. One of the most critical prosodic cues for word segmentation is stress pattern. In German as well as in English, the most frequent stress pattern of bisyllabics is the trochee, in which stress is placed on the first syllable. Using a passive oddball design, German 5-month-olds were examined with respect to their ability to discriminate different stress patterns of bisyllabics. Infants were grouped retrospectively based on their production performance at the ages of 12 and 24 months. In contrast to matched controls, infants with very low word production displayed event-related brain potentials with a significantly reduced amplitude of the discrimination response, i.e. a Mismatch Negativity (MMN), to the trochaic stress pattern. This amplitude difference indicates impaired prosodic processing of word stress during early development and may thus be taken as an early marker of risk for SLI.
Cognitive Brain Research 10/2005; 25(1):180-7. · 3.77 Impact Factor
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ABSTRACT: This study investigates by means of the event-related brain potential whether mechanisms of lexical priming and semantic integration are already developed in 14-month-olds. While looking at coloured pictures of known objects children were presented with basic-level words that were either congruous or incongruous to the pictures. The event-related potential of 14-month-olds revealed an early negativity in the lateral frontal brain region for congruous words, and a later N400-like negativity for incongruous words. These results indicate that both lexical priming and semantic integration are already present as early as 14 months.
Neuroreport 05/2005; 16(6):653-6. · 1.66 Impact Factor
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ABSTRACT: To understand mechanisms of early language acquisition, it is important to know whether the child's brain acts in an adult-like manner when processing words in meaningful contexts. The N400, a negative component in the eventrelated potential (ERP) of adults, is a sensitive index of semantic processing reflecting neural mechanisms of semantic integration into context. In the present study, we investigated whether the mechanisms indexed by the N400 are already working during early language acquisition. While 19-month-olds were looking at sequentially presented pictures, they were acoustically presented with words that were either congruous or incongruous to the picture content. The ERP averaged across the group of 55 children revealed an N400-like semantic incongruity effect in addition to an early phonological-lexical priming effect. The results suggest that both lexical expectations facilitating early phonological processing and mechanisms of semantic priming facilitating integration into semantic context are already present in 19-month-olds. The child's specific comprehension abilities are reflected in strength, latency, and hemispheric differences of the semantic incongruity effect. Spatio-temporal differences in that effect, thus, indicate changes in the organization of brain activity correlated with the child's behavioral development.
Journal of Cognitive Neuroscience 11/2004; 16(8):1465-77. · 5.18 Impact Factor
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ABSTRACT: Language acquisition crucially depends on the ability of the child to segment the incoming speech stream. Behavioral evidence supports the hypothesis that infants are sensitive to the rhythmic properties of the language input. We recorded event-related potentials (ERPs) to varying stress patterns of two syllable items in adults as well as in 4- and 5-month-old infants using a mismatch negativity (MMN) paradigm. Adult controls displayed a typical MMN to the trochaic item (stress on the first syllable) as well as to the iambic (stress on the second syllable) item. At the age of 4 months, no reliable discrimination response was seen. However, at the age of 5 months, a significant mismatch response (MMR) was observed for the trochaic item, indicating that the trochee, i.e. the most common stress pattern in German, was separated consistently from the iambic item. Hence, the present data demonstrate a clear development between 4 and 5 months with respect to the processing of different stress patterns relevant for word recognition. Moreover, possible contributions of different filter settings to the morphology of the mismatch response in infants are discussed.
Cognitive Brain Research 02/2004; 18(2):149-61. · 3.77 Impact Factor
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ABSTRACT: We recorded event-related potentials (ERPs) in 2-month-old infants in two different states of alertness: awake and asleep. Syllables varying in vowel duration (long vs short) were presented in an oddball paradigm, known to elicit a mismatch brain response. ERPs of both groups showed a mismatch response reflected in a positivity followed by a frontal negativity. While the positivity was present as a function of the stimulus type (present for long deviants only), the negativity varied as a function of the state of alertness (present for awake infants only). These data indicate a functional separation between precognitive and cognitive aspects of duration mismatch essential for the distinction between long and short vowels during early infancy.
Neuroreport 08/2002; 13(10):1251-4. · 1.66 Impact Factor
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Psychophysiology, v.41, 772-782 (2004).
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Kognitive Entwicklungsneuropsychologie, 84-100 (2007).
