1. Cook J, Barbalat G, Blakemore SJ. {{Top-down modulation of the perception of other people in schizophrenia and autism}}. {Front Hum Neurosci}. 2012; 6: 175.
Accurately and efficiently perceiving social cues such as body movements and facial expressions is important in social interaction. Accurate social perception of this kind does not solely rely on « bottom-up » visual processing but is also subject to modulation by « top-down » signals. For example, if instructed to look for signs of happiness rather than fear, participants are more likely to categorize facial expressions as happy-this prior expectation biases subsequent perception. Top-down modulation is also important in our reactions to others. For example, top-down control over imitation plays an important role in the development of smooth and harmonious social interactions. This paper highlights the importance of top-down modulation in our perception of, and reactions to, others. We discuss evidence that top-down modulation of social perception and imitation is atypical in Autism Spectrum Conditions and in schizophrenia, and we consider the effect this may have on the development of social interactions for individuals with these developmental disorders.
Lien vers le texte intégral (Open Access ou abonnement)
2. Desai MU, Divan G, Wertz FJ, Patel V. {{The discovery of autism: Indian parents’ experiences of caring for their child with an autism spectrum disorder}}. {Transcult Psychiatry}. 2012.
The current study investigated the lived experience of 12 parents of children with an Autism Spectrum Disorder in everyday cultural contexts in Goa, India. Narratives from parents collected between 2009 and 2010 were analyzed using the procedures of phenomenological psychology. Four temporal phases of parents’ experience emerged from these data. Findings showed that the earliest phase of the child’s life was a period of relative normalcy and social cohesion. In the second phase, the child’s behaviors began to disrupt the everyday social order, but parents viewed these unexpected behaviors as temporary. In the third phase, parents’ observations in public situations, along with assessments of others, led to a qualitative shift in which parents began to perceive that there was a persisting problem interfering with their child’s social and practical activities. In the fourth phase, parents grappled with developing their child’s capacities to meet existing practical opportunities in the local society, while attempting to reshape the social world to accommodate the abilities and limits of children like their own. Parents’ fundamental concerns throughout their journey were: learning to meet new and unfamiliar challenges as parents, caring for their child’s basic needs, and finding an engaging niche with a sense of belonging for their child in the everyday milieu. Both culture-specific and potentially universal levels of experience are delineated in the overall findings. Implications for culturally sensitive research and practice in India and other low- and middle-income countries are discussed.
Lien vers le texte intégral (Open Access ou abonnement)
3. Fukushima J. {{[Neurophysiological studies in autism spectrum disorders–comparison with those in schizophrenia]}}. {Seishin Shinkeigaku Zasshi}. 2012; 114(4): 335-48.
There have been reports that autism spectrum disorders (ASD) share common symptoms with schizophrenia. Several imaging studies showed the overlap of the impaired brain circuit in ASD and schizophrenia. Accordingly, differential diagnoses between adult ASD and schizophrenia without positive symptoms are sometimes difficult. We examined whether they show common results in functional MRI studies involving viewing photos of different facial expressions, such as angry, happy, sad, and neutral faces. We also examined oculomotor tasks that consist of saccadic and smooth pursuit eye movements in the two groups of patients. In fMRI studies, 15 schizophrenia patients (8 females) and 15 ASD patients (9 females) who met the criteria for DSM-IV participated. For the typically developed (TD) control group, 15 subjects (6 females) with no history of neurological or psychiatric disorders were recruited from the community. There was no significant difference in ages and sex ratios among these three groups. ANOVA comparison indicated that the ASD group showed significantly reduced activity in the right fusiform gyrus (FG) on viewing sad, happy, and neutral expressions but higher activity in the right mirror neuron system in the frontal cortex during viewing an angry expression. These results suggest a disturbance of the FG for face recognition and an excessive reaction to angry faces in ASD subjects. On the other hand, schizophrenics showed significantly reduced activation in widespread cortical areas, including the frontal, parietal, temporal, and occipital cortex, in comparison with TD and ASD individuals. We also examined voluntary control of saccadic and smooth pursuit eye movements in 13 adult subjects aged 20-35 with ASD (5 females) and compared the results with the performance of 13 TDs. Saccadic and smooth pursuit eye movements were recorded using an infrared system. Compared with TDs, 38% of the ASD subjects showed higher error rates in the anti-saccade task. However, in horizontal sinusoidal smooth pursuit, they showed normal gains. On the other hand, about 70% of 99 schizophrenics showed abnormalities in the antisaccade tasks. In the smooth pursuit task, 60-70% of schizophrenics showed a lower gain than controls. In this study, although all of the ASD subjects were adults and the number examined was relatively small, their abnormalities in fMRI and eye movement tasks were milder than those of schizophrenics.
4. Karim K, Cook L, O’Reilly M. {{Diagnosing autistic spectrum disorder in the age of austerity}}. {Child Care Health Dev}. 2012.
BACKGROUND: Diagnosing autistic spectrum disorder is a challenge, typically involving myriad professionals. In the current climate we explore how diagnosis is managed in the real world by professionals. METHODS: Using semi-structured interviews we thematically analyse data from psychiatrists, paediatricians and educational psychologists. RESULTS: While there is some consistency across and within these groups there are also a number of variances, and several important issues are highlighted. These include the problem of time and resources, the issue of location for diagnosis, the value of diagnostic tools and schedules, the need for supporting information, the difficulty of multi-agency working, the relevance of a physical examination and the eventual diagnostic label. CONCLUSIONS: In the current economic climate and considering changes in guidelines there is a need to evaluate current service provision and enhance services. However, attention needs to be paid to the practical and realistic application of the suggested guidance.
Lien vers le texte intégral (Open Access ou abonnement)
5. Kirsten TB, Chaves-Kirsten GP, Chaible LM, Silva AC, Martins DO, Britto LR, Dagli ML, Torrao AS, Palermo-Neto J, Bernardi MM. {{Hypoactivity of the central dopaminergic system and autistic-like behavior induced by a single early prenatal exposure to lipopolysaccharide}}. {J Neurosci Res}. 2012.
The aim of the present study was to evaluate the behavioral patterns associated with autism and the prevalence of these behaviors in males and females, to verify whether our model of lipopolysaccharide (LPS) administration represents an experimental model of autism. For this, we prenatally exposed Wistar rats to LPS (100 mug/kg, intraperitoneally, on gestational day 9.5), which mimics infection by gram-negative bacteria. Furthermore, because the exact mechanisms by which autism develops are still unknown, we investigated the neurological mechanisms that might underlie the behavioral alterations that were observed. Because we previously had demonstrated that prenatal LPS decreases striatal dopamine (DA) and metabolite levels, the striatal dopaminergic system (tyrosine hydroxylase [TH] and DA receptors D1a and D2) and glial cells (astrocytes and microglia) were analyzed by using immunohistochemistry, immunoblotting, and real-time PCR. Our results show that prenatal LPS exposure impaired communication (ultrasonic vocalizations) in male pups and learning and memory (T-maze spontaneous alternation) in male adults, as well as inducing repetitive/restricted behavior, but did not change social interactions in either infancy (play behavior) or adulthood in females. Moreover, although the expression of DA receptors was unchanged, the experimental animals exhibited reduced striatal TH levels, indicating that reduced DA synthesis impaired the striatal dopaminergic system. The expression of glial cell markers was not increased, which suggests that prenatal LPS did not induce permanent neuroinflammation in the striatum. Together with our previous finding of social impairments in males, the present findings demonstrate that prenatal LPS induced autism-like effects and also a hypoactivation of the dopaminergic system. (c) 2012 Wiley Periodicals, Inc.
Lien vers le texte intégral (Open Access ou abonnement)
6. Knaus TA, Tager-Flusberg H, Foundas AL. {{Sylvian fissure and parietal anatomy in children with autism spectrum disorder}}. {Behav Neurol}. 2012.
Autism spectrum disorder (ASD) is characterized by deficits in social functioning and language and communication, with restricted interests or stereotyped behaviors. Anatomical differences have been found in the parietal cortex in children with ASD, but parietal subregions and associations between Sylvian fissure (SF) and parietal anatomy have not been explored. In this study, SF length and anterior and posterior parietal volumes were measured on MRI in 30 right-handed boys with ASD and 30 right-handed typically developing boys (7-14 years), matched on age and non-verbal IQ. There was leftward SF and anterior parietal asymmetry, and rightward posterior parietal asymmetry, across groups. There were associations between SF and parietal asymmetries, with slight group differences. Typical SF asymmetry was associated with typical anterior and posterior parietal asymmetry, in both groups. In the atypical SF asymmetry group, controls had atypical parietal asymmetry, whereas in ASD there were more equal numbers of individuals with typical as atypical anterior parietal asymmetry. We did not find significant anatomical-behavioral associations. Our findings of more individuals in the ASD group having a dissociation between cortical asymmetries warrants further investigation of these subgroups and emphasizes the importance of investigating anatomical relationships in addition to group differences in individual regions.
Lien vers le texte intégral (Open Access ou abonnement)
7. Luo R, Sanders SJ, Tian Y, Voineagu I, Huang N, Chu SH, Klei L, Cai C, Ou J, Lowe JK, Hurles ME, Devlin B, State MW, Geschwind DH. {{Genome-wide Transcriptome Profiling Reveals the Functional Impact of Rare De Novo and Recurrent CNVs in Autism Spectrum Disorders}}. {Am J Hum Genet}. 2012.
Copy-number variants (CNVs) are a major contributor to the pathophysiology of autism spectrum disorders (ASDs), but the functional impact of CNVs remains largely unexplored. Because brain tissue is not available from most samples, we interrogated gene expression in lymphoblasts from 244 families with discordant siblings in the Simons Simplex Collection in order to identify potentially pathogenic variation. Our results reveal that the overall frequency of significantly misexpressed genes (which we refer to here as outliers) identified in probands and unaffected siblings does not differ. However, in probands, but not their unaffected siblings, the group of outlier genes is significantly enriched in neural-related pathways, including neuropeptide signaling, synaptogenesis, and cell adhesion. We demonstrate that outlier genes cluster within the most pathogenic CNVs (rare de novo CNVs) and can be used for the prioritization of rare CNVs of potentially unknown significance. Several nonrecurrent CNVs with significant gene-expression alterations are identified (these include deletions in chromosomal regions 3q27, 3p13, and 3p26 and duplications at 2p15), suggesting that these are potential candidate ASD loci. In addition, we identify distinct expression changes in 16p11.2 microdeletions, 16p11.2 microduplications, and 7q11.23 duplications, and we show that specific genes within the 16p CNV interval correlate with differences in head circumference, an ASD-relevant phenotype. This study provides evidence that pathogenic structural variants have a functional impact via transcriptome alterations in ASDs at a genome-wide level and demonstrates the utility of integrating gene expression with mutation data for the prioritization of genes disrupted by potentially pathogenic mutations.
