Gamma oscillations in the human EEG as signature of use-dependent formation and activation of cortical networks related to memory processes

神经科学中最基本的难题之一是大脑如何整合其分散的皮层活动。Hebb（1949）提出了一种强大的联想机制，指出不同大脑区域的特定功能是通过“细胞组合”的动态结合而整合的。这个想法自提出以来就引起了研究人员的兴趣，但直到过去十年，证明其存在的技术一直缺乏。最近，人类基本感知加工的脑电图研究表明，在伽玛波段（大至20 Hz）的振荡脑活动与这些网络的激活相关。此外，在一系列的初步研究中，我们证明了伽马波段反应（GBRS）不仅与基本感知有关，而且反映了不同形式的记忆。基于这些发现，本项目将检验gbr反映与助记功能相关的大规模网络的使用依赖的形成/激活的假设。这些网络的动态将在不同的记忆系统（内隐和外显记忆）和多个检索过程（例如熟悉与回忆）中进行研究。此外，我们将推动分析技术的发展，以揭示大脑振荡活动的皮层（和可能的皮层下）来源。拟议项目的结果将显著补充人类记忆的当代理论模型。

One of the more fundamental puzzles in neuroscience is how the brain integrates its distributed cortical activities. A powerful associative mechanism was proposed by Hebb (1949), which stated that specific functions of different brain areas are integrated by dynamical binding of ¿cell assemblies¿. This idea has intrigued investigators since its formulation, but the technology to demonstrate its existence had been lacking until the past decade. Recently, human EEG studies on basic perceptual processing have shown that oscillatory brain activity in the garnma band (bigger as 20 Hz) correlates with the activation of such networks. Furthermore, in a series of preliminary studies, we demonstrated that gamma band responses (GBRS) are not only related to basic perception, but reflect different forms of memory. Based on these findings, the present project will examine the hypothesis that GBRs mirror the use-dependent fonnation/activation of large-scale networks related to mnemonic ftmctioning. The dynamics of these networks will be investigated in different memory systems (implicit and explicit memory) and due to multiple retrieval processes (e.g. familiarity versus recollection). In addition, we will impel the development of analysis techniques to uncover cortical (and possibly subcortical) sources of oscillatory brain activity. The outcome of the proposed project will significantly complement contemporary theoretical models of human memory.