Functional Brain Imaging Studies Of Human Visual Cogniti

利用功能性脑成像在完整脑中研究了调节视觉感知、注意力和记忆的人类神经系统。功能性磁共振成像（fMRI）被用来精确测量局部血流动力学的变化与选定的视觉感知和记忆任务的性能。这些血流动力学变化是神经活动局部变化的指标。人类的纹外视皮层，像猕猴一样，被组织成腹侧物体视觉流和背侧空间视觉流。腹侧物体视觉通路被发现有一个功能架构，它对面孔和不同类别的物体（如房屋、椅子、动物和工具）产生不同的反应模式。这些与类别相关的反应模式在不同的受试者中非常一致。研究发现，面部知觉涉及腹侧颞叶皮层和上级颞叶沟，前者更多地参与面部身份的表征，后者更多地参与面部结构中对社会交流很重要的可变方面的表征，如表情和眼睛注视方向。完整的物体和空间视觉加工流，包括后部纹外投射和前额叶投射，参与物体和空间视觉工作记忆。不同的前额叶区域与物体和空间视觉工作记忆相关。空间工作记忆激活了上级额沟中的一个区域，就在人类额叶视野的前面。三，在解剖学和功能上不同的前额叶区域中，额下回被确定参与对象的工作记忆。事件相关功能磁共振成像被用来区分补充机制跟踪项目在工作记忆中-一个跟踪重复的项目，以促进忽略干扰，一个跟踪目标的工作记忆搜索。

Human neural systems that mediate visual perception, attention, and memory were investigated in the intact brain with functional brain imaging. Functional magnetic resonance imaging (fMRI) was used to measure precisely localized hemodynamic changes associated with the performance of selected visual perceptual and mnemonic tasks. These hemodynamic changes are indices of local changes in neural activity. Human extrastriate visual cortex, like that of the macaque monkey, is organized into a ventral object vision stream and a dorsal spatial vision stream. The ventral object vision pathway was found to have a functional architecture that produces different patterns of response for faces and different categories of objects, such as houses, chairs, animals, and tools. These category-related patterns of response are remarkably consistent across subjects. Face perception was found to involve both the ventral temporal cortex, which is more involved in the representation of face identity, and the superior temporal sulcus, which is more involved in the representation of changeable aspects of the facial configuration that are important for social communincation, such as expression and eye gaze direction. The complete object and spatial visual processing streams, including posterior extrastriate and prefrontal projections, participate in object and spatial visual working memory. Different prefrontal areas were associated with object and spatial visual working memory. Spatial working memory activated a region in the superior frontal sulcus just anterior to the human frontal eye field. Three, anatomically and functionally distinct prefrontal regions in the middle and inferior frontal gyri were identified that participate in object working memory. Event-related fMRI was used to distinguish complementary mechanisms for tracking items in working memory - one for tracking repetitions of items to facilitate ignoring distracters and one for tracking the target of a working memory search.