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1.  Abnormal autonomic and associated brain activities during rest in autism spectrum disorder 
Brain  2014;137(1):153-171.
Autism spectrum disorders are associated with social and emotional deficits, the aetiology of which are not well understood. A growing consensus is that the autonomic nervous system serves a key role in emotional processes, by providing physiological signals essential to subjective states. We hypothesized that altered autonomic processing is related to the socio-emotional deficits in autism spectrum disorders. Here, we investigated the relationship between non-specific skin conductance response, an objective index of sympathetic neural activity, and brain fluctuations during rest in high-functioning adults with autism spectrum disorder relative to neurotypical controls. Compared with control participants, individuals with autism spectrum disorder showed less skin conductance responses overall. They also showed weaker correlations between skin conductance responses and frontal brain regions, including the anterior cingulate and anterior insular cortices. Additionally, skin conductance responses were found to have less contribution to default mode network connectivity in individuals with autism spectrum disorders relative to controls. These results suggest that autonomic processing is altered in autism spectrum disorders, which may be related to the abnormal socio-emotional behaviours that characterize this condition.
doi:10.1093/brain/awt294
PMCID: PMC3891443  PMID: 24424916
autism; autonomic nervous system; emotion; skin conductance; resting state
2.  The 5-HT2A receptor and serotonin transporter in Asperger’s Disorder: a PET study with [11C]MDL 100907 and [11C]DASB 
Psychiatry research  2011;194(3):230-234.
Evidence from biochemical, imaging, and treatment studies suggest abnormalities of the serotonin system in autism spectrum disorders, in particular in frontolimbic areas of the brain. We used the radiotracers [11C]MDL 100907 and [11C]DASB to characterize the 5-HT2A receptor and serotonin transporter in Asperger’s Disorder. 17 individuals with Asperger’s Disorder (age = 34.3 ± 11.1 yr) and 17 healthy controls (age = 33.0 ± 9.6 yr) were scanned with [11C]MDL 100907. Of the 17 patients, eight (age = 29.7 ± 7.0 yr) were also scanned with [11C]DASB, as were eight healthy controls (age = 28.7 ± 7.0 yr). Patients with Asperger’s Disorder and healthy control subjects were matched for age, gender, and ethnicity, and all had normal intelligence. Metabolite-corrected arterial plasma inputs were collected and data analyzed by 2 tissue-compartment modeling. The primary outcome measure was regional binding potential BPND. Neither regional [11C]MDL 100907 BPND nor [11C]DASB BPND were statistically different between the Asperger’s and healthy subjects. This study failed to find significant alterations in binding parameters of 5-HT2A receptors and serotonin transporters in adult subjects with Asperger’s Disorder.
doi:10.1016/j.pscychresns.2011.04.007
PMCID: PMC3225493  PMID: 22079057
autism spectrum disorders; 5-HT2A receptor; Asperger’s Disorder; positron emission tomography; serotonin transporter; serotonin
3.  Functional deficits of the attentional networks in autism 
Brain and Behavior  2012;2(5):647-660.
Attentional dysfunction is among the most consistent observations of autism spectrum disorders (ASD). However, the neural nature of this deficit in ASD is still unclear. In this study, we aimed to identify the neurobehavioral correlates of attentional dysfunction in ASD. We used the Attention Network Test-Revised and functional magnetic resonance imaging to examine alerting, orienting, and executive control functions, as well as the neural substrates underlying these attentional functions in unmedicated, high-functioning adults with ASD (n = 12) and matched healthy controls (HC, n = 12). Compared with HC, individuals with ASD showed increased error rates in alerting and executive control, accompanied by lower activity in the mid-frontal gyrus and the caudate nucleus for alerting, and by the absence of significant functional activation in the anterior cingulate cortex (ACC) for executive control. In addition, greater behavioral deficiency in executive control in ASD was correlated with less functional activation of the ACC. These findings of behavioral and neural abnormalities in alerting and executive control of attention in ASD may suggest core attentional deficits, which require further investigation.
doi:10.1002/brb3.90
PMCID: PMC3489817  PMID: 23139910
Alerting; anterior cingulate cortex; attentional networks; autism; executive control
4.  In vivo 1H-magnetic resonance spectroscopy study of the attentional networks in autism 
Brain research  2010;1380:198-205.
Attentional dysfunction is one of the most consistent findings in individuals with autism spectrum disorders (ASD). However, the significance of such findings for the pathophysiology of autism is unclear. In this study, we investigated cellular neurochemistry with proton magnetic resonance spectroscopy imaging (1H-MRS) in brain regions associated with networks subserving alerting, orienting, and executive control of attention in patients with ASD. Concentrations of cerebral N-acetyl-aspartate (NAA), creatinine + phosphocreatinine, choline-containing compounds, myo-inositol (Ins) and glutamate + glutamine (Glx) were determined by 3 T 1H-MRS examinations in 14 high-functioning medication-free adults with a diagnosis of ASD and 14 age- and IQ-matched healthy controls (HC) in the anterior cingulate cortex (ACC), thalamus, temporoparietal junction (TPJ), and areas near or along the intraparietal sulcus (IPS). Compared to HC group, the ASD group showed significantly lower Glx concentrations in right ACC and reduced Ins in left TPJ. This study provides evidence of abnormalities in neurotransmission related to networks subserving executive control and alerting of attention, functions which have been previously implicated in ASD pathogenesis.
doi:10.1016/j.brainres.2010.12.057
PMCID: PMC3073642  PMID: 21185269
autism; spectroscopy; glutamate; anterior cingulate cortex; intraparietal sulcus; myo-inositol
5.  Autism genome-wide copy number variation reveals ubiquitin and neuronal genes 
Nature  2009;459(7246):569-573.
Autism spectrum disorders (ASDs) are childhood neurodevelopmental disorders with complex genetic origins1–4. Previous studies focusing on candidate genes or genomic regions have identified several copy number variations (CNVs) that are associated with an increased risk of ASDs5–9. Here we present the results from a whole-genome CNV study on a cohort of 859 ASD cases and 1,409 healthy children of European ancestry who were genotyped with ~550,000 single nucleotide polymorphism markers, in an attempt to comprehensively identify CNVs conferring susceptibility to ASDs. Positive findings were evaluated in an independent cohort of 1,336 ASD cases and 1,110 controls of European ancestry. Besides previously reported ASD candidate genes, such as NRXN1 (ref. 10) and CNTN4 (refs 11, 12), several new susceptibility genes encoding neuronal cell-adhesion molecules, including NLGN1 and ASTN2, were enriched with CNVs in ASD cases compared to controls (P = 9.5 × 10−3). Furthermore, CNVs within or surrounding genes involved in the ubiquitin pathways, including UBE3A, PARK2, RFWD2 and FBXO40, were affected by CNVs not observed in controls (P = 3.3 × 10−3). We also identified duplications 55 kilobases upstream of complementary DNA AK123120 (P = 3.6 × 10−6). Although these variants may be individually rare, they target genes involved in neuronal cell-adhesion or ubiquitin degradation, indicating that these two important gene networks expressed within the central nervous system may contribute to the genetic susceptibility of ASD.
doi:10.1038/nature07953
PMCID: PMC2925224  PMID: 19404257

Results 1-5 (5)