Event-related alpha and theta responses in a visuo-spatial working memory task
Event-related alpha and theta responses in a visuo-spatial working memory task
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DOI：
10.1016/s1388-2457(02)00303-6
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发表时间：
2002-12-01
影响因子：
4.7
通讯作者：
de Geus, EJC
中科院分区：
文献类型：
--
作者：
Bastiaansen, MCM;Posthuma, D;de Geus, EJC
目的：探讨视空间工作记忆过程中θ和α节律的反应性。方法：对174名被试进行延迟反应任务。他们必须记住目标刺激在电脑屏幕上的空间位置，时间间隔为1或4个S。目标要么在整个时间间隔内保持可见(感官测试)，要么在150毫秒后消失(记忆测试)。分析了4~12 Hz频段脑电诱发频段功率(IBP)的变化。结果：呈现靶刺激后，在较低频段(大致为4~8 HZ)，诱发频段功率呈阶段性增加，且有一个后极值。在保留间期内，枕顶α功率持续增加，额角功率下降。最重要的是，记忆测试显示IBP？额叶电极上的theta频段比感觉试验时降低。结论：靶点出现后相位功率的增加反映了靶点位置的编码。持续的theta下降，在记忆测试中更大，初步被解释为反映了视觉空间工作记忆的过程。(C)2002爱思唯尔科学爱尔兰有限公司。保留所有权利。
Objective: To explore the reactivity of the theta and alpha rhythms during visuo-spatial working memory.Methods: One hundred and seventy-four subjects performed a delayed response task. They had to remember the spatial location of a target stimulus on a computer screen for a 1 or a 4 s retention interval. The target either remained visible throughout the entire interval (sensory trials) or disappeared after 150 ms (memory trials). Changes in induced band power (IBP) in the electroencephalogram (EEG) were analyzed in 4 narrow, individually adjusted frequency bands between 4 and 12 Hz.Results: After presentation of the target stimulus, a phasic power increase was found, irrespective of condition and delay interval, in the lower (roughly, 4-8 Hz) frequency bands, with a posterior maximum. During the retention interval, sustained occipital-parietal alpha power increase and frontal theta power decrease were found. Most importantly, the memory trials showed larger IBP? decreases in the theta band over frontal electrodes than the sensory trials.Conclusions: The phasic power increase following target onset is interpreted to reflect encoding of the target location. The sustained theta decrease, which is larger for memory trials, is tentatively interpreted to reflect visuo-spatial working memory processes. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.