初级视皮层（V1）在视觉选择性注意的作用及神经机制

The role of primary visual cortex (V1) in visual attention is controversial. The current dominant view is the feedback hypothesis, according to which V1 is involved in visual attention at a later processing stage, via a top-down feedback from higher visual cortex to V1, but the earliest processing stage occurred in V1 is not modulated by attention. However, recent evidence from event-related potential (ERP) studies have shown that the earliest visual cortical response, C1 component, is modulated by attention. Because of the early peak latency (80 ms) and presumable V1 origin of the C1 component,it has been argued that V1 activity may be directly modulated by attention at the initial processing stage. Consistent with this "direct modulation" point of view, we have previously proposed that the C1 attentional effect may be affected by a variety of experimental factors, such as attention type, stimulus property, perceptual load of the stimuli, and attentional load. In this proposal, we will conduct ERP studies to further identify the factors affecting the C1 attentional effect. Moreover, functional magnetic resonance imaging (fMRI) technique will be combined with ERP technique to provide both high spatial and temporal resolution for the underlying brain mechanisms. Specifically, the stimulus saliency, the perceptual load of the stimuli, and attention load will be manipulated in separate studies to identify how these factors contribute to the attentional effects on the early ERP components, such as C1, P1 and N1. The ERP effects of voluntary and involuntary attention will also be compared. Our key research questions are: （1）Is the C1 component directly modulated by attention? （2）What are the factors affecting the C1 attentional effects? Results may provide emperical data for the debate between "direct modulation" and "feedback" hypotheses and extend our understanding of the underlying neural mechnisms of visual selective attention.

关于初级视皮层（V1）在视觉注意中的作用问题，存在"反馈"和"直接调制"两种观点之争。当前主流观点为"反馈"假说。然而事件相关电位（ERP）的研究发现，源于V1的C1成分受注意的调制，提示"直接调制"的存在。与此种"直接调制"观点一致，我们提出，C1注意效应的产生，可能受一系列实验因素（例如，知觉负载、注意负载等）的影响。本项目拟运用ERP技术并结合功能磁共振（fMRI）技术，考察刺激的saliency、知觉负载、注意负载、情绪等因素对C1注意效应的影响，以探究V1在选择性注意中的作用及机制。研究的关键问题是：（1）C1成分到底是否受注意的直接调制？（2）C1的注意效应究竟受哪些因素的影响？研究结果可能为"直接调制"和"反馈"假说之争提供进一步的实验数据，并深化我们对视觉选择性注意的神经机制的理解。

本项目主要利用行为学和事件相关电位（ERP）技术，对视觉注意以及面孔知觉的神经机制展开了研究。项目就初级视皮层在选择性注意中的作用、面孔刺激加工的选择性注意、基于物体的注意、类别内和类别间的注意控制设置、RSVP下注意选择的时间和空间特性等研究课题，进行了深入的探讨。主要研究成果：（1）对V1在选择性注意早期阶段的作用，特别是C1注意效应，应持开放又谨慎的态度并进一步明确研究参数；（2）对面孔的构型和特征信息的选择性注意在时间先后及神经机制上存在差异，构型先于特征；对面孔的情绪和性别信息的自动化加工程度不同；与异族面孔相比，对本族面孔存在无意识加工优势；（3）选择性注意可以基于语义物体，且语义物体可以被拓展至基于偏旁部首而形成的单字；基于物体的注意理论应探讨目标不确定性的重要作用，不确定性除了位置不确定性，至少包括感觉不确定性；（4）基于特征与基于类别的注意控制定势可以在注意的早期阶段被独立激活，在加工后期被整合并受注意资源的调制；（5）RSVP下视觉搜索时选择性注意的时空交互受到目标增强和分心物抑制两种因素的影响。这些结果对于理解选择性注意的作用和机制提供了新数据和新视角。本基金资助的相关研究成果已经发表于Biological Psychology, Psychophysiology, Neuropsychologia等国际刊物上，共15篇（含3篇已接受），其中SCI 论文14篇，CSCI 论文1篇。