The cerebellum is one of the most consistent sites of neuroanatomic abnormality in autism, yet it is still unclear how such pathology impacts cerebellar function. In normal subjects, we previously demonstrated with functional magnetic resonance imaging (fMRI) a dissociation between cerebellar regions involved in attention and those involved in a simple motor task, with motor activation localized to the anterior cerebellum ipsilateral to the moving hand. The purpose of the present investigation was to examine activation in the cerebella of autistic patients and normal control subjects performing this motor task.
We studied eight autistic patients and eight matched normal subjects, using fMRI. An anatomic region-of-interest approach was used, allowing a detailed examination of cerebellar function.
Autistic individuals showed significantly increased motor activation in the ipsilateral anterior cerebellar hemisphere relative to normal subjects, in addition to atypical activation in contralateral and posterior cerebellar regions. Moreover, increased activation was correlated with the degree of cerebellar structural abnormality.
These findings strongly suggest dysfunction of the autistic cerebellum that is a reflection of cerebellar anatomic abnormality. This neurofunctional deficit might be a key contributor to the development of certain diagnostic features of autism (e.g., impaired communication and social interaction, restricted interests, and stereotyped behaviors).
"the examination to the neural organization of extremely simple motor tasks, i.e. repetitive finger movement (Müller et al. 2001, 2003; Allen et al. 2004). At our knowledge, the only study (Hodge et al. 2010) systematically assesses specific implicit learning related regions in the cerebellar hemispheres, as the lobules VI and VII of the posterior lateral cerebellum, documenting no differences between ASD children and comparison participants. "
[Show abstract][Hide abstract] ABSTRACT: Background. Individuals with autism spectrum disorders (ASDs) are characterized by social communication difficulties and behavioural rigidity. Difficulties in learning from others are one of the most devastating features of this group of conditions. Nevertheless, the nature of learning difficulties in ASDs is still unclear. Given the relevance of implicit learning for social and communicative functioning, a link has been hypothesized between ASDs and implicit learning deficit. However, studies that have employed formal testing of implicit learning in ASDs provided mixed results.
Method. We undertook a systematic search of studies that examined implicit learning in ASDs using serial reaction time (SRT), alternating serial reaction time (ASRT), pursuit rotor (PR), and contextual cueing (CC) tasks, and synthesized the data using meta-analysis. A total of 11 studies were identified, representing data from 407 individuals with ASDs and typically developing comparison participants.
Results. The results indicate that individuals with ASDs do not differ in any task considered [SRT and ASRT task: standardized mean difference (SMD) −0.18, 95% confidence interval (CI) −0.71 to 0.36; PR task: SMD −0.34, 95% CI −1.04 to 0.36; CC task: SMD 0.27, 95% CI −0.07 to 0.60].
Conclusions. Based on our synthesis of the existing literature, we conclude that individuals with ASDs can learn implicitly, supporting the hypothesis that implicit learning deficits do not represent a core feature in ASDs.
Psychological Medicine 08/2014; 45(05):1-14. DOI:10.1017/S0033291714001950 · 5.94 Impact Factor
"to neurotypical controls when engaged in simple motor tasks (Allen et al., 2004); children with ASD demonstrate reduced functional connectivity (FC) compared to typically developing children throughout the motor control network during finger sequencing (Mostofsky et al., 2009). In addition to these structural and task-related findings, resting state fMRI investigations have reported reduced interhemispheric connectivity between right and left somatomotor cortex (Anderson et al., 2011), as well as potentially delayed functional segregation of the precentral gyrus (PCG) in children with ASD compared to their typically developing (Nebel et al., 2014). "
[Show abstract][Hide abstract] ABSTRACT: Motor impairments are prevalent in children with autism spectrum disorders (ASD) and are perhaps the earliest symptoms to develop. In addition, motor skills relate to the communicative/social deficits at the core of ASD diagnosis, and these behavioral deficits may reflect abnormal connectivity within brain networks underlying motor control and learning. Despite the fact that motor abnormalities in ASD are well-characterized, there remains a fundamental disconnect between the complexity of the clinical presentation of ASD and the underlying neurobiological mechanisms. In this study, we examined connectivity within and between functional subregions of a key component of the motor control network, the precentral gyrus, using resting state functional Magnetic Resonance Imaging data collected from a large, heterogeneous sample of individuals with ASD as well as neurotypical controls. We found that the strength of connectivity within and between distinct functional subregions of the precentral gyrus was related to ASD diagnosis and to the severity of ASD traits. In particular, connectivity involving the dorsomedial (lower limb/trunk) subregion was abnormal in ASD individuals as predicted by models using a dichotomous variable coding for the presence of ASD, as well as models using symptom severity ratings. These findings provide further support for a link between motor and social/communicative abilities in ASD.
Frontiers in Systems Neuroscience 05/2014; 8:80. DOI:10.3389/fnsys.2014.00080
"These considerations are reinforced by our studies which not only showed severe gross motor problems in children with autism spectrum disorders, but also that children selected on the basis of poor gross motor performance showed a high prevalence of symptoms of autism. Thus, we agree with the suggestion of Allen et al. (2004), Belmonte et al. (2004) and Piek & Dyck (2004) that cerebellar dysfunction constitutes a common neurobiological link between motor problems and ASD. However, the cerebellum is not the only brain structure involved in ASD. "
[Show abstract][Hide abstract] ABSTRACT: Children with neurodevelopmental disorders often show problems in movement behaviour. Clinical motor features such as clumsiness, odd postures, hyperactivity and tics occur frequently in children with psychiatric conditions. Most dance/movement therapists recognize these, and consequently tailor treatment to the abilities of their clients. In view of treatment strategies, it is important to know which motor features are associated with which psychiatric conditions, and how movement problems be influenced by movement interventions. Therefore, this article focuses on clinical movement features, gross motor problems, neurodevelopmental aspects and movement interventions for children with emotional, behavioural and autism spectrum disorders.
The Arts in Psychotherapy 04/2014; 41(2). DOI:10.1016/j.aip.2014.02.007 · 0.58 Impact Factor
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