The distributional and embodied contexts of verbs in caregiver-infant interactions.

The process by which infants learn verbs through daily social interactions is not well-understood. This study investigated caregivers' use of verbs, which have highly abstract meanings, during unscripted toy-play. We examined how verbs co-occurred with distributional and embodied factors including pronouns, caregivers' manual actions, and infants' locomotion, gaze, and object-touching. Object-action verbs were used significantly more often during caregiver-infant joint attention interactions. Movement and cognition verbs showed distinct co-occurrences with different contexts. Cognition and volition verbs were differentiated by pronouns. These findings provide evidence for how verb acquisition may be supported by the distributional and embodied contexts in caregiver-infant interactions.

Maternal discourse continuity and infants' actions organize 12-month-olds' language exposure during object play.

Infant language learning depends on the distribution of co-occurrences within language-between words and other words-and between language content and events in the world. Yet infant-directed speech is not limited to words that refer to perceivable objects and actions. Rather, caregivers' utterances contain a range of syntactic forms and expressions with diverse attentional, regulatory, social, and referential functions. We conducted a distributional analysis of linguistic content types at the utterance level, and demonstrated that a wide range of content types in maternal speech can be distinguished by their distribution in sequences of utterances and by their patterns of co-occurrence with infants' actions. We observed free-play sessions of 38 12-month-old infants and their mothers, annotated maternal utterances for 10 content types, and coded infants' gaze target and object handling. Results show that all content types tended to repeat in consecutive utterances, whereas preferred transitions between different content types reflected sequences from attention-capturing to directing and then descriptive utterances. Specific content types were associated with infants' engagement with objects (declaratives, descriptions, object names), with disengagement from objects (talk about attention, infant's name), and with infants' gaze at the mother (affirmations). We discuss how structured discourse might facilitate language acquisition by making speech input more predictable and/or by providing clues about high-level form-function mappings.

Spatial compartmentalization of signaling imparts source-specific functions on secreted factors.

Efficient regeneration requires multiple cell types acting in coordination. To better understand the intercellular networks involved and how they change when regeneration fails, we profile the transcriptome of hematopoietic, stromal, myogenic, and endothelial cells over 14 days following acute muscle damage. We generate a time-resolved computational model of interactions and identify VEGFA-driven endothelial engagement as a key differentiating feature in models of successful and failed regeneration. In addition, the analysis highlights that the majority of secreted signals, including VEGFA, are simultaneously produced by multiple cell types. To test whether the cellular source of a factor determines its function, we delete VEGFA from two cell types residing in close proximity: stromal and myogenic progenitors. By comparing responses to different types of damage, we find that myogenic and stromal VEGFA have distinct functions in regeneration. This suggests that spatial compartmentalization of signaling plays a key role in intercellular communication networks.

A formal MIM specification and tools for the common exchange of MIM diagrams: an XML-Based format, an API, and a validation method.

BACKGROUND: The Molecular Interaction Map (MIM) notation offers a standard set of symbols and rules on their usage for the depiction of cellular signaling network diagrams. Such diagrams are essential for disseminating biological information in a concise manner. A lack of software tools for the notation restricts wider usage of the notation. Development of software is facilitated by a more detailed specification regarding software requirements than has previously existed for the MIM notation. RESULTS: A formal implementation of the MIM notation was developed based on a core set of previously defined glyphs. This implementation provides a detailed specification of the properties of the elements of the MIM notation. Building upon this specification, a machine-readable format is provided as a standardized mechanism for the storage and exchange of MIM diagrams. This new format is accompanied by a Java-based application programming interface to help software developers to integrate MIM support into software projects. A validation mechanism is also provided to determine whether MIM datasets are in accordance with syntax rules provided by the new specification. CONCLUSIONS: The work presented here provides key foundational components to promote software development for the MIM notation. These components will speed up the development of interoperable tools supporting the MIM notation and will aid in the translation of data stored in MIM diagrams to other standardized formats. Several projects utilizing this implementation of the notation are outlined herein. The MIM specification is available as an additional file to this publication. Source code, libraries, documentation, and examples are available at http://discover.nci.nih.gov/mim.

Adjacent and Non-Adjacent Word Contexts Both Predict Age of Acquisition of English Words: A Distributional Corpus Analysis of Child-Directed Speech.

Children show a remarkable degree of consistency in learning some words earlier than others. What patterns of word usage predict variations among words in age of acquisition? We use distributional analysis of a naturalistic corpus of child-directed speech to create quantitative features representing natural variability in word contexts. We evaluate two sets of features: One set is generated from the distribution of words into frames defined by the two adjacent words. These features primarily encode syntactic aspects of word usage. The other set is generated from non-adjacent co-occurrences between words. These features encode complementary thematic aspects of word usage. Regression models using these distributional features to predict age of acquisition of 656 early-acquired English words indicate that both types of features improve predictions over simpler models based on frequency and appearance in salient or simple utterance contexts. Syntactic features were stronger predictors of children's production than comprehension, whereas thematic features were stronger predictors of comprehension. Overall, earlier acquisition was predicted by features representing frames that select for nouns and verbs, and by thematic content related to food and face-to-face play topics; later acquisition was predicted by features representing frames that select for pronouns and question words, and by content related to narratives and object play.

Contingencies Between Infants' Gaze, Vocal, and Manual Actions and Mothers' Object-Naming: Longitudinal Changes From 4 to 9 Months.

Infants' early motor actions help organize social interactions, forming the context of caregiver speech. We investigated changes across the first year in social contingencies between infant gaze and object exploration, and mothers' speech. We recorded mother-infant object play at 4, 6, and 9 months, identifying infants' and mothers' gaze and hand actions, and mothers' object naming and general utterances. Mothers named objects more when infants vocalized, looked at objects or the mother's face, or handled multiple objects. As infants aged, their increasing object exploration created opportunities for caregiver contingencies and changed how gaze and hands accompany object naming over time.