Brain Imaging and Neurostimulation Laboratory, Department of Neurology, University Hospital Eppendorf, Martinistr. 52, Hamburg, Germany.
Neurosci Biobehav Rev. 2010 Jun;34(7):1015-22. doi: 10.1016/j.neubiorev.2009.12.006. Epub 2009 Dec 16.
Neural correlates of control mechanisms in human working memory are discussed at two levels in this review: (i) at 'item level', where in multi-item working memory information needs to be organized into sequential memory representations, and (ii) at a 'process level', indicating the integration and control of a variety of cognitive functions involved in working memory, independent of item representations per se. It will be discussed that at both levels electroencephalographic theta activity is responsible for control of working memory functions. On item level, exact phase coding, e.g., approached by coupling between theta and gamma oscillations or phase resetting of theta frequency, is suggested to integrate information into working memory representations. At process level interregional theta synchronization is discussed to integrate brain structures necessary for working memory. When discussing the specificity of theta activity for control of working memory processes it will be suggested that theta oscillations might play an important general integrative role in organization of brain activity. And as working memory often involves a variety of cognitive processes which need to be coordinated there is particular need for an integrative brain mechanism like theta activity as suggested in this review.
（i）在“项目水平”上，在多项目工作记忆中，信息需要组织成连续的记忆表示，以及（ii）在“过程水平”上，表明涉及工作记忆的各种认知功能的整合和控制，而不依赖于项目表示本身。本文将讨论在这两个层面上，脑电θ活动都负责工作记忆功能的控制。在项目水平上，建议通过θ和γ振荡的耦合或θ频率的相位复位来实现精确的相位编码，从而将信息整合到工作记忆表示中。在过程水平上，讨论了区域间θ同步以整合工作记忆所必需的脑结构。在讨论θ活动对工作记忆过程控制的特异性时，本文提出，θ振荡可能在大脑活动的组织中起着重要的整体整合作用。并且由于工作记忆通常涉及到需要协调的各种认知过程，因此像θ活动这样的整合脑机制尤其需要，正如本文所建议的那样。
