拓扑变化对跳视的影响及面孔识别在跳视准备期间的增强效应
文献类型：学位论文
| 作者 | 林海 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 胡新天 |
| 关键词 | 跳视 拓扑视知觉 自下而上 新物体出现 面孔识别 |
| 其他题名 | The effects of topological changes on oculomotor and face recognition increases during saccade preparation |
| 学位专业 | 神经生物学 |
| 中文摘要 | 当我们睁开眼睛，视网膜会接收到大量的视觉信息，但只有极少数的信息能通过快速眼睛运动——跳视，为视网膜上中央凹所接受，在大脑中得到进一步的处理。那么，到底什么样的信息可以使我们的眼睛产生跳视运动，从而把它们呈现在中央凹上呢？另外，尽管眼睛运动速度很快，很容易出现误差，我们仍然能把那些需要进一步处理的重要信息准确地呈现在中央凹上，这又是如何实现的呢？ 对于第一个问题，总所周知，新物体的出现（abrupt onset）这一得到广泛研究的现象，能够有效地吸引注意和眼睛运动。陈霖院士提出的拓扑视知觉理论认为物体的拓扑性质（连通性和洞的个数），相对于其他几何性质（方向和大小），是一种整体性质，它主要在视知觉的早期得到加工。因此，他提出拓扑变化（物体的拓扑性质发生变化），在视觉上有可能被知觉为“新物体”的出现。那么，拓扑变化应该和新物体的出现一样，能吸引注意和眼动，并且这种吸引是自下而上的（bottom-up）。因而，本研究通过采用经典的眼动捕获（oculomotor capture）的范式来研究拓扑视知觉。此外，我们还结合自由眼动（free-viewing）的范式，设计了一种新颖的实验范式。在被试进行一些简单的视觉搜索任务时，与任务无关的刺激（拓扑变化和非拓扑变化）能够吸引眼睛被动地向其运动，严重干扰了被试任务的进行。更重要的是，我们比较了多对图形的变化，对多种非拓扑因素进行了控制，最后得到了一致的结果：拓扑变化相对于非拓扑变化，能够显著地吸引眼动。这种自下而上的吸引说明拓扑知觉在视觉早期占据着重要的地位，并且它也许可以解释眼睛被动运动的方向，或者说，拓扑性质是决定物体能否吸引眼睛产生跳视运动的重要因素。 对于第二个问题，我们关心的是眼睛运动之前的视觉加工处理过程。我们已经知道，在跳视的准备阶段，对于位于将要发生的跳视落点处的物体，其一些基本性质（例如，朝向）的处理会得到加强。而面孔是一类非常特别的物体：我们分别用不同的大脑脑区去识别面孔和其他物体。有趣的是，也有证据表明面孔识别和其他基本性质的检测一样，发生在视觉处理的早期阶段。我们的研究发现面孔也具有类似的处理加强的效应：从跳视发生前大约120ms开始，随着跳视的到来，面孔的识别逐渐加强，并且视觉空间也发生了改变。这些结果表明：即将出现的跳视可以为加工跳视落点处的视觉信息做好准备，并且有可能通过增加跳视落点处的空间分辨率来为接下来的跳视准确定位。 |
| 英文摘要 | When we open our eyes, the retina will receive large amounts of information, but only a minority of them can be selected to be further processed in our brain, which is mostly received by the fovea of the retina. Then, what kind of information can attract our eyes’ movements and make itself received by the fovea? Besides, how can we accurately present the information wanted to be further processed onto the fovea? For the first question, it is well known that the appearance of a new object (abrupt onset), which is a typical and widely studied stimulus, can effectively capture attention and oculomotor. Meanwhile, according to Chen’s theory of “early topological perception”, the topological properties (such as connectedness and the number of holes) of objects are global with respect to other local geometric properties (such as orientation and size) and are mainly perceived in early visual processing. He even proposed that the topological change (the change in topological properties of objects) was possibly regarded as the appearance of a “new object” in vision. Then the topological change should capture attention and oculomotor just like abrupt onset, which is bottom-up. In our study, we employed the traditional paradigm of oculomotor-capturing to discuss topological perception. Besides, we also implemented a novel behavioral method, combining two paradigms of oculomotor-capturing and free-viewing. And we got consistent results: topological changes significantly attract the eye movement in a bottom-up way, in contrast with non-topological changes. For the second question, it needs to discuss the processing before eye movement. We have already known that just before eye movement onset, the processing of some basic features, such as the orientation, of an object improves at the saccade landing point. Faces are a special kind of objects, which are processed in different and specialized brain areas than other types of objects. Interestingly, there is also evidence that indicates faces are processed in early visual processing stages similar to basic features. In our study, faces were found to have this similar effect of enhancement. Starting ~ 120 ms before a saccade to a target face, independent of whether or not the face was surrounded by other faces, the face recognition gradually improved and the spatial extent changed as saccade onset was approaching. These results suggest that an upcoming saccade prepares the visual system for new information about faces at the saccade landing site and may reduce the background in a crowd to target the intended face. |
| 语种 | 中文 |
| 公开日期 | 2014-06-18 |
| 源URL | [http://159.226.149.42:8088/handle/152453/7904]  |
| 专题 | 昆明动物研究所_神经系统编码 |
| 推荐引用方式 GB/T 7714 | 林海. 拓扑变化对跳视的影响及面孔识别在跳视准备期间的增强效应[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：昆明动物研究所
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