Investigating syntax in autism: Comparisons with SLI, links with cognition Recent work exploring syntax in autism spectrum disorders (ASD) has identified morphosyntactic deficits and argued that these are independent of non-verbal reasoning. More specifically, researchers have now claimed that subgroups with ASD have syntactic profiles reminiscent of Specific Language Impairment (SLI), the latter showing a dissociation between language deficits and non-verbal intelligence. With this work, we investigate the nature of syntactic impairment in ASD, its parallelism with SLI and its potential relation to other aspects of cognition, namely non-verbal intelligence, working memory and theory of mind (ToM). We focus on a clinical marker of SLI that has scarcely been studied in ASD, namely 3rd person accusative clitic production, which has moreover been hypothesized to solicit working memory Downloaded by [La Trobe University] at 13:53 31 May 2016A c c e p t e d M a n u s c r i p t 2 resources. We also explore 1st person accusative clitic production, largely preserved in SLI but hypothesized to be specifically affected in ASD due to reported difficulties with pronouns of the 1st and 2nd person, arguably related to difficulties in ToM.Our participants included 21 individuals with ASD (aged 5-16), 22 individuals with SLI (aged 5-16) of similar age, as well as age-matched and younger controls. Experimental tasks were conducted to evaluate the production of 1st and 3rd person accusative clitics, the latter being a clinical marker of syntactic impairment. We also administered standardized tasks assessing general morphosyntax, verbal working memory (digit-span tasks and non-word repetition), nonverbal reasoning (Raven's Progressive Matrices) and ToM (Sally-Anne).Overall scores for both clinical groups reveal quantitatively similar deficits for 3rd person accusative clitics and general morphosyntax. However upon closer inspection a significant subgroup of children with ASD showed intact grammatical skills. The only weakness identified across the entire ASD population was for 1st person clitics, which was mastered by children with SLI. However the task used to elicit these required perspective shifting and thus the lower scores which resulted can be accounted for in terms of the well-documented ToM deficits in ASD. This is further supported by the observation that better scores at ToM tasks led to improved performance with 1st person accusative clitics. In addition, difficulties on all working memory measures were revealed for ASD and SLI and crucially found to correlate only with performance on 3rd person clitics in both groups. In contrast, non-verbal reasoning did not correlate with any syntactic measures.

Normalization of language performance does not generalize at adolescence in the context of MMHL. The fact that an effect of the severity of HL was found only after childhood might be because linguistic development is basically complete at adolescence. Prior to this time, this effect could be obscured by developmental rhythms that vary from child to child.

Some theories of Developmental Language Disorder (DLD) explain the linguistic deficits observed in terms of limitations in non-linguistic cognitive systems such as working memory. The goal of this research is to clarify the relationship between working memory and the processing of complex sentences by exploring the performance of 28 French-speaking children with DLD aged five to fourteen years and 48 typically developing children of the same age in memory and linguistic tasks. We identified predictive relationships between working memory and the comprehension and repetition of complex sentences in both groups. As for syntactic measures in spontaneous language, it is the complex spans that explain the major part of the variance in the control children. In children with DLD, however, simple spans are predictive of these syntactic measures. Our results thus reveal a robust relationship between working memory and syntactic complexity, with clinical implications for the treatment of children with DLD.

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Histone variants are structural components of eukaryotic chromatin that can replace replication-coupled histones in the nucleosome. The histone variant macroH2A.1.1 contains a macrodomain able to bind NAD+ derived metabolites. Here, we report that macroH2A.1.1 is rapidly induced during myogenic differentiation through a switch in alternative splicing. Importantly, myotubes lacking macroH2A.1.1 display a defect in mitochondrial respiratory capacity. We find that the metabolite-interacting macrodomain is essential for sustaining optimal mitochondrial function, but dispensable for gene regulation. Through direct binding, macroH2A.1.1 inhibits basal poly-ADP ribose polymerase 1 activity and thus reduces nuclear NAD+ consumption. Consequentially, accumulation of the NAD+ precursor NMN allows the maintenance of mitochondrial NAD+ pools critical for respiration.Our data indicate that macroH2A.1.1-containing chromatin regulates mitochondrial respiration by limiting nuclear NAD+ consumption and establishing a buffer of NAD+ precursors in differentiated cells.