Functional Communication Within a Perceptual Network Processing Letters and Pseudoletters
Functional Communication Within a Perceptual Network Processing Letters and Pseudoletters
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DOI：
10.1097/wnp.0b013e318230da5f
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发表时间：
2011-10-01
影响因子：
2.4
通讯作者：
Herdman, Anthony T.
中科院分区：
文献类型：
--
作者：
Herdman, Anthony T.
许多研究已经确定了人类腹侧视觉流中的区域对物体识别和分类是重要的；然而，关于感知信息如何在视觉网络中传递的知识仍然有限。目前的理论假设，如果传入的感官信息和内部表征之间存在高度对应，那么物体就会被迅速识别，如果没有，那么物体就需要额外的详细处理。从目前的脑磁图研究来看，事件相关反应显示了两个主要影响。对熟悉字母的N1m峰值延迟比对不熟悉的伪字母的N1m峰值延迟早约15毫秒，对伪字母的N2m峰值延迟比对字母的N2m峰值延迟更负。事件相关的波束形成分析发现，这些影响发生在双侧视觉皮质内，N2m效应右侧偏侧。此外，功能连通性分析显示，枕区之间的γ波段（50-80 Hz）振荡相位同步对字母的影响大于对伪字母的影响（约85毫秒）。然而，在245到375毫秒之间的较晚时间间隔内，伪字母在更分散的枕叶网络中引发了比字母更大的伽马带相位同步。这些发现表明，熟悉的对象处理至少从85毫秒开始，这可能表示与内部模板的初始匹配。此外，不熟悉的对象处理持续的时间比熟悉的对象长，这可能反映出对没有经验的对象的更多关注，以确定他们的身份和/或巩固一个新的模板，以帮助未来的识别。
Many studies have identified regions within human ventral visual stream to be important for object identification and categorization; however, knowledge of how perceptual information is communicated within the visual network is still limited. Current theories posit that if a high correspondence between incoming sensory information and internal representations exists, then the object is rapidly identified, and if there is not, then the object requires extra detailed processing. Event-related responses from the present magnetoencephalography study showed two main effects. The N1m peak latencies were approximately 15 milliseconds earlier to familiar letters than to unfamiliar pseudoletters, and the N2m was more negative to pseudoletters than to letters. Event-related beamforming analyses identified these effects to be within bilateral visual cortices with a right lateralization for the N2m effect. Furthermore, functional connectivity analyses revealed that gamma-band (50-80 Hz) oscillatory phase synchronizations among occipital regions were greater to letters than to pseudoletters (around 85 milliseconds). However, during a later time interval between 245 and 375 milliseconds, pseudoletters elicited greater gamma-band phase synchronizations among a more distributed occipital network than did letters. These findings indicate that familiar object processing begins by at least 85 milliseconds, which could represent an initial match to an internal template. In addition, unfamiliar object processing persisted longer than that for familiar objects, which could reflect greater attention to inexperienced objects to determine their identity and/or to consolidate a new template to aid in future identification.