Pesonen Mirka, Björnberg Christian Haarala, Hämäläinen Heikki, Krause Christina M
Cognitive Science Unit, Department of Psychology, University of Helsinki, P.O. Box 9, 00014 Helsinki, Finland.
Neurosci Lett. 2006 May 15;399(1-2):45-50. doi: 10.1016/j.neulet.2006.01.053. Epub 2006 Feb 21.
Event-related desynchronization (ERD) and event-related synchronization (ERS) responses of 1-30 Hz EEG frequencies during the different stages of an auditory Sternberg memory task were examined. The ERD/ERS responses were examined separately for successive memory set items (four) and for the two recognition conditions (YES/NO). The presentation of the memory set elicited ERS responses in the theta and alpha frequencies, and also beta ERD responses. These ERD/ERS responses elicited during encoding were found to evolve with successive memory set item presentation. The ERD/ERS responses elicited during the presentation of the probe dissociated significantly between the two recognition conditions (YES/NO). When the probe was included in the memory set (YES condition), recognition elicited stronger alpha and beta frequency ERD responses as compared to the NO condition. The findings from the current study verify that alpha ERD/ERS responses robustly dissociate between auditory encoding and recognition. The increasing alpha ERS responses with increasing memory set item presentation during encoding may be correlates of the functioning phonological loop, active memory maintenance and/or attention. The alpha ERD responses during recognition are undoubtedly associated with auditory memory search processes and distinguish between previously presented versus not presented verbal material. We propose that alpha ERD/ERS responses reflect explicitly auditory memory processes, discriminating between auditory encoding and recognition. Theta ERS responses may be associated with working memory processes, and possibly more specifically with the functioning of the central executive. Beta ERD/ERS responses may reflect also cognitive and/or memory processing, rather than merely the activity of the motor cortices.
研究了听觉斯特恩伯格记忆任务不同阶段1-30Hz脑电频率的事件相关去同步化（ERD）和事件相关同步化（ERS）反应。分别针对连续的记忆集项目（四个）和两种识别条件（是/否）检查了ERD/ERS反应。记忆集的呈现引发了θ和α频率的ERS反应，以及β频率的ERD反应。发现在编码过程中引发的这些ERD/ERS反应会随着连续记忆集项目的呈现而变化。在探测刺激呈现期间引发的ERD/ERS反应在两种识别条件（是/否）之间有显著差异。当探测刺激包含在记忆集中（是条件）时，与否条件相比，识别引发更强的α和β频率ERD反应。当前研究的结果证实，α频率的ERD/ERS反应在听觉编码和识别之间有明显差异。在编码过程中，随着记忆集项目呈现数量的增加，α频率的ERS反应增强，这可能与语音回路的功能、主动记忆维持和/或注意力有关。识别过程中的α频率ERD反应无疑与听觉记忆搜索过程相关，并能区分先前呈现的与未呈现的言语材料。我们认为，α频率的ERD/ERS反应明确反映了听觉记忆过程，区分了听觉编码和识别。θ频率的ERS反应可能与工作记忆过程有关，更具体地说，可能与中央执行系统的功能有关。β频率的ERD/ERS反应也可能反映认知和/或记忆处理，而不仅仅是运动皮层的活动。
