Marko Mollie K, Crocetti Deana, Hulst Thomas, Donchin Opher, Shadmehr Reza, Mostofsky Stewart H
1 Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
2 Centre for Neurodevelopmental and Imaging Research, Kennedy Krieger Institute, Baltimore, Maryland, USA.
Brain. 2015 Mar;138(Pt 3):784-97. doi: 10.1093/brain/awu394. Epub 2015 Jan 20.
Autism spectrum disorder is a developmental disorder characterized by deficits in social and communication skills and repetitive and stereotyped interests and behaviours. Although not part of the diagnostic criteria, individuals with autism experience a host of motor impairments, potentially due to abnormalities in how they learn motor control throughout development. Here, we used behavioural techniques to quantify motor learning in autism spectrum disorder, and structural brain imaging to investigate the neural basis of that learning in the cerebellum. Twenty children with autism spectrum disorder and 20 typically developing control subjects, aged 8-12, made reaching movements while holding the handle of a robotic manipulandum. In random trials the reach was perturbed, resulting in errors that were sensed through vision and proprioception. The brain learned from these errors and altered the motor commands on the subsequent reach. We measured learning from error as a function of the sensory modality of that error, and found that children with autism spectrum disorder outperformed typically developing children when learning from errors that were sensed through proprioception, but underperformed typically developing children when learning from errors that were sensed through vision. Previous work had shown that this learning depends on the integrity of a region in the anterior cerebellum. Here we found that the anterior cerebellum, extending into lobule VI, and parts of lobule VIII were smaller than normal in children with autism spectrum disorder, with a volume that was predicted by the pattern of learning from visual and proprioceptive errors. We suggest that the abnormal patterns of motor learning in children with autism spectrum disorder, showing an increased sensitivity to proprioceptive error and a decreased sensitivity to visual error, may be associated with abnormalities in the cerebellum.
自闭症谱系障碍是一种发育障碍，其特征是社交和沟通技能缺陷以及重复和刻板的兴趣与行为。虽然不属于诊断标准的一部分，但自闭症患者存在一系列运动障碍，这可能是由于他们在整个发育过程中学习运动控制的方式异常所致。在此，我们运用行为技术对自闭症谱系障碍中的运动学习进行量化，并利用脑结构成像来研究小脑这种学习的神经基础。20名8至12岁的自闭症谱系障碍儿童和20名发育正常的对照受试者在握住机器人操作器的手柄时进行伸手动作。在随机试验中，伸手动作受到干扰，导致通过视觉和本体感觉感知到的误差。大脑从这些误差中学习，并在随后的伸手中改变运动指令。我们将从误差中学习作为该误差感觉模态的函数进行测量，发现自闭症谱系障碍儿童在从本体感觉感知到的误差中学习时表现优于发育正常的儿童，但在从视觉感知到的误差中学习时表现不如发育正常的儿童。先前的研究表明，这种学习依赖于小脑前部一个区域的完整性。在此我们发现，延伸至小叶VI的小脑前部以及小叶VIII的部分区域在自闭症谱系障碍儿童中比正常情况小，其体积可由从视觉和本体感觉误差中学习的模式预测。我们认为，自闭症谱系障碍儿童异常的运动学习模式，即对本体感觉误差的敏感性增加而对视觉误差的敏感性降低，可能与小脑异常有关。
