Emerging Linguistic Functions in Early Infancy

This paper presents results from experimental studies on early language acquisition in infants and attempts to interpret the experimental results within the framework of the Ecological Theory of Language Acquisition (ETLA) recently proposed by (Lacerda et al., 2004a). From this perspective, the infant’s first steps in the acquisition of the ambient language are seen as a consequence of the infant’s general capacity to represent sensory input and the infant’s interaction with other actors in its immediate ecological environment. On the basis of available experimental evidence, it will be argued that ETLA offers a productive alternative to traditional descriptive views of the language acquisition process by presenting an operative model of how early linguistic function may emerge through interaction

Comparing spontaneous cross-modal magnitude matching in infants and adults

It has been proposed that young infants, in contrast to adults, base similarities in stimuli across modalities on quantitative aspects rather than on qualitative aspects. To investigate the spontaneous quantitative matching across modalities in adults and infants, 12 adults and 32 infants watched film sequences while their looking behavior was recorded using an eye-tracker. The film sequences depicted three objects that changed in size (visual magnitude) over time while brown noise was played, with intensity matching the size envelope of the objects to different degrees. The results show that adults to a greater extent attend to visual prominence than do the infants. Background Broadly speaking, perception can be either amodal or modality specific. Modality specific properties (e.g. pitch and color) can be perceived through one sensory channel only, while amodal features can be perceived in different modalities, e.g. intensity can be perceived both through auditory and visual modality channels (Lewcowiz & Turkewitz, 1980). It has been proposed that the individual's attention to different properties of an event differ at different stages of development (e.g. Schneirla, 1966). According to Schneirla's ecological Approach-Withdrawal theory, early in development, organisms respond to stimuli based primarily on their quantitative characteristics like their intensity. Through the interaction of maturation and experience, organisms later start to respond to qualitative modality-specific aspects such as pitch and color, with low intensity stimuli leading to approach behavior and high intensity stimuli leading to withdrawal behavior (Schneirla, 1966). While adults are able to tell the difference and find similarities in modality specific events, evidence supports that young infants mainly find similarities based on quantitative aspects of stimulation (e.g. Lewkowicz

Ecological Theory of Language Acquisition

This poster outlines an Ecological Theory of Language Acquisition (ETLA). The theory views the early phases of the language acquisition process as an emergent consequence of the interaction between the infant and its linguistic environment. The newborn infant is considered to be linguistically and phonetically naïve but endowed with the ability to register a wide range of multi-sensory inputs along with the ability to detect similarity between the multi-sensory stimuli it is exposed to. The initial steps of the language acquisition process are explained as unintended and inevitable consequences of the infant’s multisensory interaction with the adult. The theoretical model deriving from ETLA is tested using the experimental data presented in the two additional contributions from our research team (Gustavsson et al, “Integration of audiovisual information in 8-months-old infants”; Lacerda, Marklund et al. “On the linguistic implications of context-bound adult-infant interactions”). The generality of the ETLA’s concept is likely to be of significance for a wide range of scientific areas, like robotics, where a central issue concerns addressing general problems of how organisms or systems might develop the ability to tap on the structure of the information embedded in their operating environments

On the linguistic implications of context-bound adult-infant interactions

This poster presents a study of the linguistic information potentially available in adult speech directed to 3-month-old infants. The repetitive nature of the speech directed to young infants and the ecological context of the adult-infant natural interaction setting are analyzed in the light of the “Ecological theory of language acquisition” proposed by Lacerda et al. (2004, this volume). The analysis of transcripts of adult-infant interaction sessions suggests that enough information to derive general noun associations may be available as a consequence of the particular context of the adult-infant interactions during the early stages of the language acquisition process

Integration of audio-visual information in 8-months-old infants

The results from a series of perception experiments designed to test 8-month-old infants’ ability to derive linguistic information from audio-visual events are reported in this presentation. Using a visual preference technique, groups of 8-month-old infants were tested on their ability to extract linguistic information implicit in short video sequences where the images displayed different puppets and the audio tracks presented sentences describing the puppets in naturalistic infant-directed speech style. To assess the relative importance of memory and attention factors, the prosodic and syntactic structure of the speech materials was systematically changed across different groups of subjects. The experimental results are interpreted in terms of the emergentistic acquisition model discussed in the paper presented by Lacerda et al. (“Ecological theory of language acquisition”)

A crossover randomised controlled trial of oral mandibular advancement devices for obstructive sleep apnoea-hypopnoea (TOMADO)

Rationale Mandibular advancement devices (MADs) are used to treat obstructive sleep apnoea-hypopnoea syndrome (OSAHS) but evidence is lacking regarding their clinical and cost-effectiveness in less severe disease. Objectives To compare clinical- and cost-effectiveness of a range of MADs against no treatment in mild to moderate OSAHS. Measurements and methods This open-label, randomised, controlled, crossover trial was undertaken at a UK sleep centre. Adults with Apnoea-Hypopnoea Index (AHI) 5–<30/h and Epworth Sleepiness Scale (ESS) score ≥9 underwent 6 weeks of treatment with three nonadjustable MADs: self-moulded (SleepPro 1; SP1); semi-bespoke (SleepPro 2; SP2); fully-bespoke MAD (bMAD); and 4 weeks no treatment. Primary outcome was AHI scored by a polysomnographer blinded to treatment. Secondary outcomes included ESS, quality of life, resource use and cost. Main results 90 patients were randomised and 83 were analysed. All devices reduced AHI compared with no treatment by 26% (95% CI 11% to 38%, p=0.001) for SP1, 33% (95% CI 24% to 41%) for SP2 and 36% (95% CI 24% to 45%, p<0.001) for bMAD. ESS was 1.51 (95% CI 0.73 to 2.29, p<0.001, SP1) to 2.37 (95% CI 1.53 to 3.22, p<0.001, bMAD) lower than no treatment (p<0.001 for all). Compliance was lower for SP1, which was the least preferred treatment at trial exit. All devices were cost-effective compared with no treatment at a £20 000/quality-adjusted life year (QALY) threshold. SP2 was the most cost-effective up to £39 800/QALY. Conclusions Non-adjustable MADs achieve clinically important improvements in mild to moderate OSAHS and are cost-effective

Nerve growth factor induces neurite outgrowth of PC12 cells by promoting Gβγ-microtubule interaction

Background: Assembly and disassembly of microtubules (MTs) is critical for neurite outgrowth and differentiation. Evidence suggests that nerve growth factor (NGF) induces neurite outgrowth from PC12 cells by activating the receptor tyrosine kinase, TrkA. G protein-coupled receptors (GPCRs) as well as heterotrimeric G proteins are also involved in regulating neurite outgrowth. However, the possible connection between these pathways and how they might ultimately converge to regulate the assembly and organization of MTs during neurite outgrowth is not well understood. Results: Here, we report that Gβγ, an important component of the GPCR pathway, is critical for NGF-induced neuronal differentiation of PC12 cells. We have found that NGF promoted the interaction of Gβγ with MTs and stimulated MT assembly. While Gβγ-sequestering peptide GRK2i inhibited neurite formation, disrupted MTs, and induced neurite damage, the Gβγ activator mSIRK stimulated neurite outgrowth, which indicates the involvement of Gβγ in this process. Because we have shown earlier that prenylation and subsequent methylation/demethylation of γ subunits are required for the Gβγ-MTs interaction in vitro, small-molecule inhibitors (L-28 and L-23) targeting prenylated methylated protein methyl esterase (PMPMEase) were tested in the current study. We found that these inhibitors disrupted Gβγ and ΜΤ organization and affected cellular morphology and neurite outgrowth. In further support of a role of Gβγ-MT interaction in neuronal differentiation, it was observed that overexpression of Gβγ in PC12 cells induced neurite outgrowth in the absence of added NGF. Moreover, overexpressed Gβγ exhibited a pattern of association with MTs similar to that observed in NGF-differentiated cells. Conclusions: Altogether, our results demonstrate that βγ subunit of heterotrimeric G proteins play a critical role in neurite outgrowth and differentiation by interacting with MTs and modulating MT rearrangement. Electronic supplementary material The online version of this article (doi:10.1186/s12868-014-0132-4) contains supplementary material, which is available to authorized users