RESUMEN
PURPOSE: This study had 4 primary purposes: (a) to describe the oral narrative performance of typically developing African American prekindergarten children with commonly used macro- and microstructure measures; (b) to examine the concurrent and (c) predictive relations between narrative performance, spoken dialect use, vocabulary, and story comprehension; and (d) to explore change in narrative performance during the school year. METHOD: Children provided story retells of Frog Where Are You? ( Mayer, 1969) at the beginning ( n = 76) and end ( n = 146) of the school year. Retells were analyzed using the narrative assessment protocol ( Pence, Justice, & Gosse, 2007), the narrative scoring scheme ( Heilmann, Miller, & Nockerts, 2010; Heilmann, Miller, Nockerts, & Dunaway, 2010), high point analysis ( McCabe, Bliss, Barra, & Bennett, 2008), and other common indices of narrative ability (e.g., number of different words). Children also completed spoken dialect use, oral vocabulary, and story comprehension measures. RESULTS: Comparisons with data reported in the literature suggest that, on average, the children in this study performed within age-appropriate expectations on each narrative measure. In general, narrative performance was correlated with and predicted by complex syntax and vocabulary skills and was not associated with spoken dialect use. Finally, the children's narrative assessment protocol and high point analysis scores changed significantly during the school year. CONCLUSION: The results are useful in interpreting the performance of African American children during the prekindergarten school year.
Asunto(s)
Lenguaje Infantil , Narración , Negro o Afroamericano , Niño , Preescolar , Femenino , Humanos , Pruebas del Lenguaje , Masculino , Estados Unidos , VocabularioRESUMEN
The level of excitation in the brain is kept under control through inhibitory signals mainly exerted by GABA neurons. However, the molecular machinery that regulates the balance between excitation and inhibition (E/I) remains unclear. Candidate molecules implicated in this process are neuroligin (NL) adhesion molecules, which are differentially enriched at either excitatory or inhibitory contacts. In this study, we use transgenic mouse models expressing NL1 or NL2 to examine whether enhanced expression of specific NLs results in synaptic imbalance and altered neuronal excitability and animal behavior. Our analysis reveals several abnormalities selectively manifested in transgenic mice with enhanced expression of NL2 but not NL1. A small change in NL2 expression results in enlarged synaptic contact size and vesicle reserve pool in frontal cortex synapses and an overall reduction in the E/I ratio. The frequency of miniature inhibitory synaptic currents was also found to be increased in the frontal cortex of transgenic NL2 mice. These animals also manifested stereotyped jumping behavior, anxiety, impaired social interactions, and enhanced incidence of spike-wave discharges, as depicted by EEG analysis in freely moving animals. These findings may provide the neural basis for E/I imbalance and altered behavior associated with neurodevelopmental disorders.