Sysoeva Olga V, Galuta Ilia A, Davletshina Maria S, Orekhova Elena V, Stroganova Tatiana A
Center for Neurocognitive Research (MEG Center), Moscow State University of Psychology and EducationMoscow, Russia; Autism Research Laboratory, Moscow State University of Psychology and EducationMoscow, Russia.
Autism Research Laboratory, Moscow State University of Psychology and Education Moscow, Russia.
Front Neurosci. 2017 Mar 29;11:164. doi: 10.3389/fnins.2017.00164. eCollection 2017.
Excitation/Inhibition (E/I) imbalance in neural networks is now considered among the core neural underpinnings of autism psychopathology. In motion perception at least two phenomena critically depend on E/I balance in visual cortex: spatial suppression (SS), and spatial facilitation (SF) corresponding to impoverished or improved motion perception with increasing stimuli size, respectively. While SS is dominant at high contrast, SF is evident for low contrast stimuli, due to the prevalence of inhibitory contextual modulations in the former, and excitatory ones in the latter case. Only one previous study (Foss-Feig et al., 2013) investigated SS and SF in Autism Spectrum Disorder (ASD). Our study aimed to replicate previous findings, and to explore the putative contribution of deficient inhibitory influences into an enhanced SF index in ASD-a cornerstone for interpretation proposed by Foss-Feig et al. (2013). The SS and SF were examined in 40 boys with ASD, broad spectrum of intellectual abilities (63 < IQ < 127) and 44 typically developing (TD) boys, aged 6-15 years. The stimuli of small (1°) and large (12°) radius were presented under high (100%) and low (1%) contrast conditions. Social Responsiveness Scale and Sensory Profile Questionnaire were used to assess the autism severity and sensory processing abnormalities. We found that the SS index was atypically reduced, while SF index abnormally enhanced in children with ASD. The presence of abnormally enhanced SF in children with ASD was the only consistent finding between our study and that of Foss-Feig et al. While the SS and SF indexes were strongly interrelated in TD participants, this correlation was absent in their peers with ASD. In addition, the SF index but not the SS index correlated with the severity of autism and the poor registration abilities. The pattern of results is partially consistent with the idea of hypofunctional inhibitory transmission in visual areas in ASD. Nonetheless, the absence of correlation between SF and SS indexes paired with a strong direct link between abnormally enhanced SF and autism symptoms in our ASD sample emphasizes the role of the enhanced excitatory influences by themselves in the observed abnormalities in low-level visual phenomena found in ASD.
神经网络中的兴奋/抑制（E/I）失衡如今被视为自闭症精神病理学的核心神经基础之一。在运动感知中，至少有两种现象严重依赖于视觉皮层中的E/I平衡：空间抑制（SS）和空间易化（SF），分别对应随着刺激大小增加运动感知能力下降或提高的情况。虽然在高对比度下SS占主导，但在低对比度刺激下SF很明显，这是因为前者存在抑制性上下文调制，而后者存在兴奋性上下文调制。之前只有一项研究（Foss-Feig等人，2013年）在自闭症谱系障碍（ASD）中研究了SS和SF。我们的研究旨在重复之前的发现，并探讨抑制性影响不足对ASD中增强的SF指数的假定贡献——这是Foss-Feig等人（2013年）提出的解释基石。对40名患有ASD、智力能力范围广泛（63＜智商＜127）的男孩和44名年龄在6至15岁的发育正常（TD）男孩进行了SS和SF测试。在高（100%）和低（1%）对比度条件下呈现小（1°）和大（12°）半径的刺激。使用社会反应量表和感觉特征问卷来评估自闭症严重程度和感觉处理异常情况。我们发现，ASD儿童的SS指数非典型降低，而SF指数异常增强。ASD儿童中SF异常增强是我们的研究与Foss-Feig等人的研究之间唯一一致的发现。虽然SS和SF指数在TD参与者中密切相关，但在他们患有ASD的同龄人中这种相关性不存在。此外，SF指数而非SS指数与自闭症严重程度和较差的登记能力相关。结果模式部分与ASD视觉区域抑制性传递功能低下的观点一致。尽管如此，在我们的ASD样本中，SF和SS指数之间缺乏相关性，以及异常增强的SF与自闭症症状之间存在强烈的直接联系，这强调了增强的兴奋性影响本身在ASD中低水平视觉现象所观察到的异常中的作用。
