The last decade has been marked by an increased interest in relating epigenetic mechanisms to complex human behaviors, although this interest has not been balanced, accentuating various types of affective and primarily ignoring cognitive functioning. Recent animal model data support the view that epigenetic processes play a role in learning and memory consolidation and help transmit acquired memories even across generations. In this review, we provide an overview of various types of epigenetic mechanisms in the brain (DNA methylation, histone modification, and noncoding RNA action) and discuss their impact proximally on gene transcription, protein synthesis, and synaptic plasticity and distally on learning, memory, and other cognitive functions. Of particular importance are observations that neuronal activation regulates the dynamics of the epigenome's functioning under precise timing, with subsequent alterations in the gene expression profile. In turn, epigenetic regulation impacts neuronal action, closing the circle and substantiating the signaling pathways that underlie, at least partially, learning, memory, and other cognitive processes.

Lexical processing deficits in children with developmental language disorder (DLD) have been postulated to arise as sequelae of their grammatical deficits (either directly or via compensatory mechanisms) and vice versa. We examined event-related potential indices of lexical processing in children with DLD (n = 23) and their typically developing peers (n = 16) using a picture–word matching paradigm. We found that children with DLD showed markedly reduced N400 amplitudes in response both to auditorily presented words that had initial phonological overlap with the name of the pictured object and to words that were not semantically or phonologically related to the pictured object. Moreover, this reduction was related to behavioral indices of phonological and lexical but not grammatical development. We also found that children with DLD showed a depressed phonological mapping negativity component in the early time window, suggesting deficits in phonological processing or early lexical access. The results are partially consistent with the overactivation account of lexical processing deficits in DLD and point to the relative functional independence of lexical/phonological and grammatical deficits in DLD, supporting a multidimensional view of the disorder. The results also, although indirectly, support the neuroplasticity account of DLD, according to which language impairment affects brain development and shapes the specific patterns of brain responses to language stimuli.

Two experiments tested whether Russian-speaking children with Developmental Language Disorder (DLD) are sensitive to gender agreement when performing a gender decision task. In Experiment 1, the presence of overt gender agreement between verbs and/or adjectival modifiers and postverbal subject nouns memory was varied. In Experiment 2, agreement violations were introduced and the targets varied between words, pseudo-words, or pseudo-words with derivational suffixes. In both experiments, children with DLD did not differ from typically developing children in their reaction time or sensitivity to agreement features. In both groups, trials with feminine gender resulted in a higher error rate. Children with DLD displayed lower overall accuracy, which was related to differences in phonological memory in both experiments. Furthermore, in Experiment 1 group differences were not maintained after phonological memory was entered as a covariate. The results are discussed with respect to various processing and linguistic theories of DLD.

This article describes the results of an epidemiological study of developmental language disorder (DLD) in an isolated rural Russian population. We report an atypically high prevalence of DLD across all age groups when contrasted with a comparison population. The results are corroborated by a set of comparisons of school-aged children from the target population with their age peers and mean length of utterance matches from the comparison population. We also investigate the relationship between nonverbal cognition, verbal working memory, and expressive language performance in the population, and find statistically significant but small effect sizes. Finally, we describe the complex and heterogeneous structure of the phenotype in the population along with patterns of its vertical transmission on the basis of the exemplar pedigrees, and discuss the implications of our findings for genetic and clinical studies of DLD.