Development of slow oscillation-spindle coupling from infancy to toddlerhood.

Sleep has been demonstrated to support memory formation from early life on. The precise temporal coupling of slow oscillations (SOs) with spindles has been suggested as a mechanism facilitating this consolidation process in thalamocortical networks. Here, we investigated the development of sleep spindles and SOs and their coordinate interplay by comparing frontal, central, and parietal electroencephalogram recordings during a nap between infants aged 2-3 months ( = 31) and toddlers aged 14-17 months ( = 49).

Long-term memory formation for voices during sleep in three-month-old infants.

The ability to form long-term memories begins in early infancy. However, little is known about the specific mechanisms that guide memory formation during this developmental stage. We demonstrate the emergence of a long-term memory for a novel voice in three-month-old infants using the EEG mismatch response (MMR) to the word "baby".

Memory for nonadjacent dependencies in the first year of life and its relation to sleep.

Grammar learning requires memory for dependencies between nonadjacent elements in speech. Immediate learning of nonadjacent dependencies has been observed in very young infants, but their memory of such dependencies has remained unexplored. Here we used event-related potentials to investigate whether 6- to 8-month-olds retain nonadjacent dependencies and if sleep after learning affects this memory.

Sleep-dependent memory consolidation in infants protects new episodic memories from existing semantic memories.

Any experienced event may be encoded and retained in detail as part of our episodic memory, and may also refer and contribute to our generalized knowledge stored in semantic memory. The beginnings of this declarative memory formation are only poorly understood. Even less is known about the interrelation between episodic and semantic memory during the earliest developmental stages.

The reciprocal relation between sleep and memory in infancy: Memory-dependent adjustment of sleep spindles and spindle-dependent improvement of memories.

Sleep spindle activity in infants supports their formation of generalized memories during sleep, indicating that specific sleep processes affect the consolidation of memories early in life. Characteristics of sleep spindles depend on the infant's developmental state and are known to be associated with trait-like factors such as intelligence. It is, however, largely unknown which state-like factors affect sleep spindles in infancy.

The Sleeping Infant Brain Anticipates Development.

From the age of 3 months, infants learn relations between objects and co-occurring words [1]. These very first representations of object-word pairings in infant memory are considered as non-symbolic proto-words comprising specific visual-auditory associations that can already be formed in the first months of life [2-5]. Genuine words that refer to semantic long-term memory have not been evidenced prior to 9 months of age [6-9].

The origins of word learning: Brain responses of 3-month-olds indicate their rapid association of objects and words.

The present study explored the origins of word learning in early infancy. Using event-related potentials (ERP) we monitored the brain activity of 3-month-old infants when they were repeatedly exposed to several initially novel words paired consistently with each the same initially novel objects or inconsistently with different objects. Our results provide strong evidence that these young infants extract statistic regularities in the distribution of the co-occurrences of objects and words extremely quickly.

Generalization of word meanings during infant sleep.

Sleep consolidates memory and promotes generalization in adults, but it is still unknown to what extent the rapidly growing infant memory benefits from sleep. Here we show that during sleep the infant brain reorganizes recent memories and creates semantic knowledge from individual episodic experiences. Infants aged between 9 and 16 months were given the opportunity to encode both objects as specific word meanings and categories as general word meanings.

Word learning in 6-month-olds: fast encoding-weak retention.

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.

Maturing brain mechanisms and developing behavioral language skills.

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.

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.

Neurophysiological correlates of online word learning in 14-month-old infants.

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.

Brain responses in 4-month-old infants are already language specific.

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.

The processing of prosody: Evidence of interhemispheric specialization at the age of four.

Beyond its multiple functions in language comprehension and emotional shaping, prosodic cues play a pivotal role for the infant's amazingly rapid acquisition of language. However, cortical correlates of prosodic processing are largely controversial, even in adults, and functional imaging data in children are sparse. We here use an approach which allows to experimentally determine brain activations correlating to the perception and processing of sentence prosody during childhood.

Early N400 development and later language acquisition.

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.

Phonotactic knowledge and lexical-semantic processing in one-year-olds: brain responses to words and nonsense words in picture contexts.

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.

Neural correlates of syntactic processing in two-year-olds.

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.

Semantic sentence processing reflected in the event-related potentials of one- and two-year-old children.

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.

Reduced stress pattern discrimination in 5-month-olds as a marker of risk for later language impairment: neurophysiologial evidence.

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.

Lexical priming and semantic integration reflected in the event-related potential of 14-month-olds.

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.

N400-like semantic incongruity effect in 19-month-olds: processing known words in picture contexts.

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.

Discriminating scrapie and bovine spongiform encephalopathy isolates by infrared spectroscopy of pathological prion protein.

For the surveillance of transmissible spongiform encephalopathies (TSEs) in animals and humans, the discrimination of different TSE strains causing scrapie, BSE, or Creutzfeldt-Jakob disease constitutes a substantial challenge. We addressed this problem by Fourier transform-infrared (FT-IR) spectroscopy of pathological prion protein PrP27-30. Different isolates of hamster-adapted scrapie (263K, 22A-H, and ME7-H) and BSE (BSE-H) were passaged in Syrian hamsters.

Picture-word matching: flexibility in conceptual memory and pupillary responses.

The influence of levels of abstraction in picture-word matching was examined. The items each consisted of one picture and three successively presented words. Hierarchies with words for superordinate, basic, and subordinate level concepts were used (e.

Discrimination of word stress in early infant perception: electrophysiological evidence.

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.

Neural manifestation of cognitive and precognitive mismatch detection in early infancy.

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.