导　　师： 金志成

学科专业： 040201

授予学位： 博士

作　　者： ;

机构地区： 华南师范大学

摘　　要： 视觉研究一个复杂的问题，就是大脑如何解决捆绑问题。自然界中的物体是由不同的属性组成的，如形状、大小、颜色、方向等，这些属性是在大脑的不同部位加工的。以视知觉为例，颜色与形状等客体特征在枕叶到颞叶的腹侧通路内得到表征，而运动等空间特征在枕叶到顶叶的背侧通路内得到表征。因此，为把外界物体知觉成一个整体而不是个别零散的特征，就需要把散布于不同皮层区的分散信息合理地组合在一起，这就是所谓的“捆绑问题”。捆绑问题存在的一个重要证据，就是在分散注意或注意过载条件下，物体的各个特征不能在正确的位置上进行整合，从而产生客体间特征彼此交换的现象，即特征的错觉性结合/(简称IC/)。如视觉呈现两个彩色字母红X和绿O，如果被试做出绿X和红O的反应，就出现了错觉性结合。 当前，捆绑问题被公认为认知科学和神经科学的中心问题，其研究属于基础心理学的前沿领域之一，对心理过程的认知神经机制研究起到重要推动作用，同时也有助于解决意识之谜。然而，就是这样一个重要而前沿的问题，国内的研究接近于空白。即使是国外的研究，也未形成一致的结论，还存在着许多理论和实证的冲突。这项研究在系统总结与分析前人研究的基础上发现，特征捆绑研究的最大分歧在于其心理和生理机制上，对于注意及顶叶/(尤其是右顶叶皮层/)在视觉特征捆绑中的重要作用，一些研究还存在着异议。同时，前人的研究在实验范式及其测量指标上存在着不合理因素。鉴于此，该研究通过对视知觉领域的特征捆绑进行系统的实验研究，旨在考察注意这一认知因素在视觉特征捆绑中的重要作用及其作用机制，同时也探讨顶叶尤其是右顶叶皮层对视觉特征捆绑的调节作用，进而检验几种不同的特征捆绑理论。 研究基于三方面通过4个大实验10个分实验，考察了时间和空间视觉特征捆绑的认知机制及脑机制。 在视觉特征捆绑的认知机制方面。实验1主要运用认知科学的手段，通过3 个分实验，直接操纵注意这一认知变量，在集中注意和分散注意条件下，使用不 同实验范式考察注意在视觉特征捆绑中的作用，并进一步检验特征整合理论。实 验结果表明，注意在视觉特征捆绑中起重要作用，集中注意能有效地减少错觉性 结合的出现。具体地说，在不同分散注意水平下，错觉性结合错误之间存在显著 差异，表明分散注意导致错觉性结合，注意分散水平越高，错觉性结合错误越多; 而集中注意条伙有效提示/)的错觉性结合远远少于分散斜气无效提动，说明集 中注意能有效地减少错觉性结合的发生;注意对特征捆绑的调节作用表现出距离 效应，即近距离比远距离的错觉性结合错误多，提示了注意的作用机制有可能与 空间距离信息有关。 在视觉特征捆绑的神经机制方面。实验2是对一例双侧顶叶损伤患者的个案 研究，通过2个分实验，从认知神经角度考察视觉特征捆绑的脑皮层机制，以检 验顶叶在视觉特征捆绑中的作用。实验3是右顶叶局部损伤患者与正常人的对比 研究，通过2个分实验，在集中注意和分散注意条件下，考察右顶叶及空间注意 对视觉特征捆绑操作的影响。实验结果表明，双侧顶叶及右顶叶损伤严重影响了 患者的视觉特征捆绑操作成绩，这种影响与空间注意能力的减弱有关。具体来讲， 双顶叶损伤患者在捆绑操作中出现了大量的错觉性结合错误，这种组剖昔误受空 间信息的影响，同时呈现比系列呈现的刺激间形成更多的错觉性结合，近距离比 远距离的组合错误要多;右顶叶损伤患者由于空间注意受损，比正常同龄被试更 难于完成同样的捆绑任务，无论是集中注意还是分散注意刹牛下，均出现了较多 的特征组合错误和更明显的距离效应;两类损伤患者所表现出的明显距离效应和 位置效应，充分提示了顶叶在特征捆绑中的重要作用是通过空间注意来实现的。 从实验2和实验3的结果，可进一步推论出，双侧顶叶损伤很可能与分心物的抑 制有关，表现为患者经常把分心物当成靶子报告，而右顶叶损伤患者则能很好排 除分心物的干扰。 在时间范畴视觉特征捆绑的注意机制方面。实验4主要从认知行为层面模拟 了特征捆绑的时间同步性效果，通过3个分实验，以变化的实验范式，考察注意 在时间范畴视觉特征捆绑中的作用机制，进而对捆绑的时间同步性理论进行检 验。研究结果表明，.注意在时间范畴特征捆绑中的作用机制与空间视觉特征捆绑 相同，即时fh/]范围内的捆绑也是在注意的作用下按空间位置/(而不是时间/)线索进 行捆绑的。对来自于相同位置的项目时间同步性刁起作用;如果项目的时间接近 但位置不同，则不倾向于产生捆绑。即使在变化的实验范式中，仍未提供支持时 间同步性理论的有利证据，相同位置特征间的同步条件与不同位置特征间的同步 条件下，均出现较多的错觉性结合。 综上所述，对视觉特征捆绑的系统实验研究，证实了对该问题的所有假设， 视知觉领域特征捆绑的认知机制是注意的重要调节作用，其神经基础在于大脑顶 叶皮层，通过顶叶/(尤其是右顶口勺对空间注意的调节来完成的。对认知科学和脑 科学中这一前沿问题进行系统而深入的探讨，不仅可以解决当前该领域内? One of the complicated researches on vision is to find out how the brain works on the binding problem. Objects in the natural world are made of different features such as shape, size, color, direction, etc. and these features are processed in diverse parts of the brain. Take the example of the visual perception, the formal features as color and shape are represented through the pathway from occipital to temporal lobe, whereas the spatial feature as movement is conveyed by the dorsal pathway from occipital to parietal lobe. Therefore, to perceive the objects as a whole and not separately is to combine all the information that exists in different parts of the brain, and this is so-called 'binding problem'. One important evidence for its existence is that the features of the objects can not be integrated in the right position on the condition of distractive or overloading attention, and there comes the phenomenon of exchanging the features between the objects, that is to say, the illusory conjunction. For examp le, if the subjects are displayed a red X and a green O, they response as green X and red O, that is the illusory conjunction. At present time, binding is publicly regarded as the heated issue in cognitive psychology and cognitive neurology, its research belongs to the leading field and impels in the study in cognitive neural mechanism of psychological process as well as the puzzle of the consciousness. Scholars in qur country do not pay much attention to this field and even the foreign scholars can not reach an agreement in its theory and experimental results. Based on study and analysis of the previous research work, it proves that the disagreement lies in its psychological and physiological mechanism and the influence of attention and parietal lobe on feature binding. Meanwhile, there exist some irrational factors in the experimental paradigm and its measuring standard. This dissertation aims at the testimony of the function of attention as a cognitive factor and its functional mechanism, the adjusting function of parietal lobe, especially the right parietal cortex, on the visual feature binding, and therefore to testify differen t theories ' on feature binding. This research consists of four experiments which includes 10 sub-experiments to testify the cognitive and brain mechanism of the visual feature binding in the temporal and spatial domains. On the cognitive mechanism, experiment 1 carried out by 3 sub-experiments directly controls the attention as a cognitive variable confined in distractive and focal condition, to testify its function in visual feature binding with various experimental paradigm, and to further testify the feature integrity theory. It proves that attention plays an important role in visual feature binding, focal attention can effectively reduce the possibility of illusory conjunctions. To be more specific, the difference of illusory conjunction in condition of different distractive attention are significant, distractive attention leads to illusory conjunction, the higher the distractive level is, the more errors of illusory conjunction the subjects will make; illusory conjunction on the focal condition /(effective cue/) is far less than on the distractive one /(ineffective cue/), it draws a conclusion that focal attention can effectively restrain the illusory conjunction; its adjusting function is represented in distance effect, near objects are easily causing more illusory conjunctions than far ones, its functional mechanism might be related to its information of distance. On the neurological mechanism, experiment 2 carried out by 2 sub-experiments is a case study of a patient with bilateral parietal lesion, it is to testify the mechanism of parietal lobe in visual feature binding for the cognitive neural perspective. Experiment 3 is a contrast study between patients with partial lesion of the right parietal lobe and normal subjects, its 2 sub-experiments testify the right parietal lobe and spatial attention confined in distractive and focal attention conditions as well as

关 键 词： 视觉 特征捆绑 注意 错觉性结合 顶叶 特征整合理论 时间同步性 认知机制

分 类 号： [B842]

领　　域： [哲学宗教] [哲学宗教]