Pubmed du 30/12/08

Pubmed du jour

2008-12-30 12:03:50

1. Arnold JE, Bennetto L, Diehl JJ. {{Reference production in young speakers with and without autism: Effects of discourse status and processing constraints}}. {Cognition};2008 (Dec 24)

We examine the referential choices (pronouns/zeros vs. names/descriptions) made during a narrative by high-functioning children and adolescents with autism and a well-matched typically developing control group. The process of choosing appropriate referring expressions has been proposed to depend on two areas of cognitive functioning: (a) judging the attention and knowledge of one’s interlocutor, and (b) the use of memory and attention mechanisms to represent the discourse situation. We predicted possible group differences, since autism is often associated with deficits in (a) mentalizing and (b) memory and attention, as well as a more general tendency to have difficulty with the pragmatic aspects of language use. Results revealed that some of the participants with autism were significantly less likely to produce pronouns or zeros in some discourse contexts. However, the difference was only one of degree. Overall, all participants in our analysis exhibited fine-grained sensitivity to the discourse context. Furthermore, referential choices for all participants were modulated by factors related to the cognitive effort of language production.

2. Dichter GS, Belger A. {{Atypical modulation of cognitive control by arousal in autism}}. {Psychiatry Res};2008 (Dec 30);164(3):185-197.

We examined the effects of viewing high-arousal pictures on regional brain activations elicited by a cognitive control task in participants with high-functioning autism and neurotypical controls. Specifically, using event-related functional magnetic resonance imaging, we assessed the effects of brief presentations of highly arousing pictures (i.e., both very pleasant and very unpleasant) on the processing of stimuli requiring cognitive control. Similar to previous findings, when stimuli with high cognitive control demands were preceded by low-arousal pictures, individuals with autism demonstrated regional brain activations that were comparable to neurotypical control individuals. When the presentation of the cognitive control stimuli was preceded by high-arousal pictures, however, the control group was characterized by relatively greater activation in the right lateral midfrontal cortex in response to cognitive control stimuli. In contrast, preceding high-arousal stimuli did not modulate activity elicited in this region by cognitive control stimuli in the autism group. Differential modulation of right lateral midfrontal activation by high-arousal stimuli in autism is consistent with the « inefficiency model » of brain functioning in autism spectrum disorders, and contributes to a growing body of evidence that autism may be characterized by anomalous sensitivity of cognitive control brain regions to social-emotional context.