- UID
- 1333346
- 在线时间
- 小时
- 注册时间
- 2018-3-14
- 最后登录
- 1970-1-1
- 主题
- 帖子
- 性别
- 保密
|
JOURNAL ARTICLE
The Machinery of Thought
Tim Beardsley
Scientific American
Vol. 277, No. 2 (AUGUST 1997), pp. 78-83
Published by: Scientific American, a division of Nature America, Inc.
https://www.jstor.org/stable/24995875
Page Count: 6
The Devil in the Details
Having shown that the prefrontal cortex is crucial to working memory, investigators naturally want to understand its internal structure. Goldman-Rakic and her associates at Yale have found evidence that when an animal retains information about a spatial location, the prefrontal activity is confined to a specific subregion. A separate area below it is most active when an animal is remembering the appearance of an object. These findings, together with observations of the anatomy of neural pathways, led Goldman-Rakic to propose that the prefrontal cortex is organized into regions that temporarily store information about different sensory domains: one for the domain of spatial cues, one for cues relating to an object’s appearance and perhaps others for various types of cues.
There are, moreover, some indications that the human prefrontal cortex may be organized along similar domain—specific lines. A PET study reported last year by Susan M. Courtney, Leslie G. Ungerleider and their colleagues at the National Institute of Mental Health found that in humans, as in the monkeys studied earlier by Goldman-Rakic, certain brain areas are especially active during exercises that challenge working memory for visual details and for locations. Moreover, the most active brain regions lie in similar relative positions in both species.
关于大脑储存信息的机制．第一段: GP 发现大脑的不同SUBREGION 负责处理不同的信息. 这与STANDARD 观点不同. 传统观点人为大脑的EXECUTIVE INFORMAITON CENTER 管理信息处理.第二段: 有个新实验,证实GP的观点正确. 第四篇是working memory，两段。第一段介绍working memory，然后提到（人名）对人脑的前额叶进行研究，发现和spatial有关的信息是refine在一个region里处理的，于是他认为这里会分为几个region，比如处理spatial的region和处理appearance的region。但是这个观点和standard的观点相违背，传统观点是认为有一个executive system，把信息给allocate进行处理的。
Goldman-Rakic’s proposal about the organization of the prefrontal cortex argues against the standard view of the various components of working memory. The British psychologist Alan Baddely proposed in 1974 that working memory has a hierarchical structure, in which an “executive system” in the prefrontal cortex allocates processing resources to separate “slave” buffers for verbal and spatial information. The memory buffers were supposed to be well behind the prefrontal cortex. But Goldman-Rakic is unconvinced that the brain’s executive processes are confined to any particular location. Moreover, in the traditional model, memories organized by domain would lie somewhere behind the prefrontal cortex, not within it.
说脑子里面有个区域，传统认为是发指令从其它部分调取资料的，但是后来某人的研究说这部分是直接来用作存储数据的缓存的。然后有个MRI的实验，看人脸的时候这个区域有活动，然后这个MRI实验证实了某人的研究，因为看人脸不需要发指令。 关于working memory 的 大意 记不太清了：1。working memory 是和executive memory 相对的； 有人发现working memory 储存在大脑的cortex中，而原来的理论说working memory分散在cortex之外 2。另一个人发现 when recognize faces, the middle part of cortex is most active. 。。。不好意思 记不太清 不误导大家了 问题有一道较难 就问第二个人的发现可以用作什么的证据？我选的是：the middle part of cortex is most important to working memory 类似的，不知道是不是对这篇整体感觉挺难的 大家小心
The high-speed imaging capability of functional MRI is now able to help resolve the question. A study that Courtney and Ungerleider and their colleagues published in April in Nature pinpoints the part of the brain that is liveliest while working memory holds an image of a face. That region—the middle part of the prefrontal cortex—has been fingered as the crux of working memory in a variety of studies.
Yet the face-recognition task Courtney and company used does not involve any obviously executive functions, Ungerleider notes. Their findings thus contradict the view that only executive functions reside within the prefrontal cortex, but they do fit with GoldmanRakic’s scheme. Similarly, Jonathan D. Cohen of Carnegie Mellon University and his co-workers found a region of the prefrontal cortex partly overlapping the one identified by Courtney that is active while subjects remember letters seen in a sequence. The more the subjects had to remember in the Cohen experiment, the more active their prefrontal regions. So Cohen’s result also suggests that working memories are actually stored, in part, in the prefrontal cortex. Domain-specific organization “is the dominant view” of the prefrontal cortex, Wise says.
Wise himself does not subscribe to that dominant view, however. He points, for example, to a study reported in Science in May by Miller and his associates at the Massachusetts Institute of Technology. The researchers recorded from neurons in the prefrontal cortex of monkeys while they solved delayedchoice tasks that required them to remember information about both the appearance and spatial locations of objects. Over half the neurons from which Miller recorded were sensitive to both attributes, a result not expected if domain-specific organization prevails. “It argues against Goldman-Rakic’s view that identity and location are processed in different parts of the prefrontal cortex,” Miller says.
Goldman-Rakic responds that she and her colleagues have recently found hundreds of cells in part of the prefrontal cortex that respond selectively even in untrained animals to objects or faces— further evidence, she asserts, that the information in that area is organized in part by sensory domain. “We do feel the evidence is overwhelming that the functions of neurons in the prefrontal cor— tex are dictated in large part by the neurons’ sensory inputs,” she says. Moreover, Goldman-Rakic believes technical problems cast doubt on Miller’s experiment. She maintains the targets he used were too close to the center of the visual field, which could produce spurious firings.
|
本帖子中包含更多资源
您需要 登录 才可以下载或查看，没有帐号？立即注册
x
|
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2019-3-3 01:42:56
收藏
收藏
