Article

Gilbert SJ, Bird G, Brindley R, et al. Atypical recruitment of medial prefrontal cortex in autism spectrum disorders: an fMRI study of two executive function tasks

Institute of Cognitive Neuroscience and Department of Psychology, University College London, London, UK.
Neuropsychologia (Impact Factor: 3.3). 02/2008; 46(9):2281-91. DOI: 10.1016/j.neuropsychologia.2008.03.025
Source: PubMed

ABSTRACT

Recent studies have suggested an uneven profile of executive dysfunction in autism spectrum disorders (ASD). For example, some authors have reported deficits on newly developed tests of executive function sensitive to rostral prefrontal function, despite spared, or even superior, performance on other tests. We investigated the performance of a group of high-functioning participants with ASD (N=15) and an age- and IQ-matched control group (N=18) on two executive function tests, whilst undergoing functional magnetic resonance imaging (fMRI). Behaviourally, there were no significant differences between the two groups. In a classical test of executive function (random response generation), BOLD signal differed between the groups in the cerebellum but not in the frontal lobes. However, on a new test of executive function (selection between stimulus-oriented and stimulus-independent thought), the ASD group exhibited significantly greater signal-change in medial rostral prefrontal cortex (especially Brodmann Area 10) in the comparison of stimulus-oriented versus stimulus-independent attention. In addition, the new test (but not the classical test) provided evidence for abnormal functional organisation of medial prefrontal cortex in ASD. These results underline the heterogeneity of different tests of executive function, and suggest that executive functioning in ASD is associated with task-specific functional change.

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    • "It is also important to note that the paradigm used in this study was not designed to elicit global differences in executive function, as both the primary and control conditions (i.e., attend-face and attend-house) necessitated some working memory (i.e., a one-back task). Recent research on frontal lobe function in ASD shows variable results, with some executive function tasks eliciting normal or increased activation patterns (Dichter et al. 2009; Gilbert et al. 2008). Findings for DLPFC in fact parallel those of Dichter and colleagues (Dichter et al. 2009), who reported increased activation of dorsal anterior cingulate and medial prefrontal cortices in ASD during a target detection task. "
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    • "Data were shown as mean ± SE. **p < 0.01. as hippocampus pathological changes have also been reported in autism patients (Courchesne et al., 2011; Gilbert et al., 2008; Nicolson et al., 2006; Raymond et al., 1996; Rojas et al., 2004; Saitoh et al., 2001; Schumann et al., 2004; Wallace et al., 2012). Therefore, Hippocampus, termporal cortex and prefrontal cortex were evaluated for histopathological assays. "
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