Functional brain organization for visual search in ASD
Functional brain organization for visual search in ASD
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DOI：
10.1017/s1355617708081356
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发表时间：
2008-11-01
影响因子：
2.6
通讯作者：
Mueller, Ralph-Axel
中科院分区：
文献类型：
--
作者：
Keehn, Brandon;Brenner, Laurie;Mueller, Ralph-Axel
尽管先前的研究表明自闭症谱系障碍（ASD）患者擅长视觉搜索，但其潜在的神经机制仍然未知。本研究采用事件相关功能磁共振成像设计，研究了ASD儿童和正常发育（TD）儿童视觉搜索的神经功能相关性。我们使用了视觉搜索范式，通过改变集合大小（6、12或24个项目）、干扰成分（异质或同质）和目标存在来操纵搜索难度，以识别与高效和低效搜索相关的大脑区域。虽然ASD组与TD组相比没有证据表明反应时间（RT）加快，但他们确实表现出搜索效率增加，如RT通过集大小斜率测量的。激活模式也显示ASD组和TD组之间的差异，ASD组招募了包括额叶、顶叶和枕叶皮质的网络，TD组显示出不太广泛的激活，主要限于枕颞区。直接比较（均质和异质性搜索条件）显示，更大的激活在枕叶和额顶叶区域的ASD比TD参与者。这些结果表明，ASD的搜索效率可能与增强的辨别力（反映在枕叶激活）和视觉注意力自上而下的调节（与额顶叶激活相关）有关。(JINS，2008，14990 -1003.）
Although previous studies have shown that individuals with autism spectrum disorder (ASD) excel at visual search, underlying neural mechanisms remain unknown. This study investigated the neurofunctional correlates Of Visual search in children with ASD and matched typically developing (TD) children, using an event-related functional magnetic resonance imaging design. We used a Visual search paradigm, manipulating search difficulty by varying set size (6, 12, or 24 items), distractor composition (heterogeneous or homogeneous) and target presence to identify brain regions associated with efficient and inefficient search. While the ASD group did not evidence accelerated response time (RT) compared with the TD group, they did demonstrate increased search efficiency, as measured by RT by set size slopes. Activation patterns also showed differences between ASD group, which recruited a network including frontal, parietal, and occipital cortices, and the TD group, which showed less extensive activation mostly limited to occipito-temporal regions. Direct comparisons (for both homogeneous and heterogeneous search conditions) revealed greater activation in occipital and frontoparietal regions in ASD than in TD participants. These results suggest that search efficiency in ASD may be related to enhanced discrimination (reflected in occipital activation) and increased top-down modulation of visual attention (associated with frontoparietal activation). (JINS, 2008, 14 990-1003.)