Ungerleider L G, Courtney S M, Haxby J V
Laboratory of Brain and Cognition, National Institute of Mental Health, Building 10, Room 4C104, 10 Center Drive, Bethesda, MD 20892-1366, USA.
Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):883-90. doi: 10.1073/pnas.95.3.883.
Working memory is the process of actively maintaining a representation of information for a brief period of time so that it is available for use. In monkeys, visual working memory involves the concerted activity of a distributed neural system, including posterior areas in visual cortex and anterior areas in prefrontal cortex. Within visual cortex, ventral stream areas are selectively involved in object vision, whereas dorsal stream areas are selectively involved in spatial vision. This domain specificity appears to extend forward into prefrontal cortex, with ventrolateral areas involved mainly in working memory for objects and dorsolateral areas involved mainly in working memory for spatial locations. The organization of this distributed neural system for working memory in monkeys appears to be conserved in humans, though some differences between the two species exist. In humans, as compared with monkeys, areas specialized for object vision in the ventral stream have a more inferior location in temporal cortex, whereas areas specialized for spatial vision in the dorsal stream have a more superior location in parietal cortex. Displacement of both sets of visual areas away from the posterior perisylvian cortex may be related to the emergence of language over the course of brain evolution. Whereas areas specialized for object working memory in humans and monkeys are similarly located in ventrolateral prefrontal cortex, those specialized for spatial working memory occupy a more superior and posterior location within dorsal prefrontal cortex in humans than in monkeys. As in posterior cortex, this displacement in frontal cortex also may be related to the emergence of new areas to serve distinctively human cognitive abilities.
工作记忆是在短时间内主动维持信息表征以便其可供使用的过程。在猴子中，视觉工作记忆涉及一个分布式神经系统的协同活动，包括视觉皮层的后部区域和前额叶皮层的前部区域。在视觉皮层内，腹侧流区域选择性地参与物体视觉，而背侧流区域选择性地参与空间视觉。这种领域特异性似乎向前延伸至前额叶皮层，腹外侧区域主要参与物体的工作记忆，而背外侧区域主要参与空间位置的工作记忆。猴子中这种用于工作记忆的分布式神经系统的组织在人类中似乎是保守的，尽管这两个物种之间存在一些差异。与猴子相比，在人类中，腹侧流中专门用于物体视觉的区域在颞叶皮层中的位置更靠下，而背侧流中专门用于空间视觉的区域在顶叶皮层中的位置更靠上。两组视觉区域远离后颞周皮层的移位可能与大脑进化过程中语言的出现有关。虽然人类和猴子中专门用于物体工作记忆的区域同样位于腹外侧前额叶皮层，但人类中专门用于空间工作记忆的区域在背侧前额叶皮层中比猴子占据更靠上和靠后的位置。与后皮层一样，额叶皮层中的这种移位也可能与为独特的人类认知能力服务的新区域的出现有关。
