Department of Experimental Psychology, Regensburg University, Germany.
Department of Experimental Psychology, Regensburg University, Germany.
Neuroimage. 2014 Jul 1;94:155-161. doi: 10.1016/j.neuroimage.2014.03.002. Epub 2014 Mar 12.
Brain oscillations in the theta frequency band (3-8 Hz) have been shown to be critically involved in human episodic memory retrieval. In prior work, both positive and negative relationships between cortical theta power and retrieval success have been reported. This study examined the hypothesis that slow and fast cortical theta oscillations at the edges of the traditional theta frequency band are differentially related to retrieval success. Scalp EEG was recorded in healthy human participants as they performed a cued-recall episodic memory task. Slow (3 Hz) and fast (7 Hz) theta oscillations at retrieval were examined as a function of whether an item was recalled or not and as a function of the items' output position at test. Recall success typically declines with output position, due to increases in interference level. The results showed that slow theta power was positively related but fast theta power was negatively related to retrieval success. Concurrent positive and negative episodic memory effects for slow and fast theta oscillations were dissociable in time and space, showing different time courses and different spatial locations on the scalp. Moreover, fast theta power increased from early to late output positions, whereas slow theta power was unaffected by items' output position. Together with prior work, the results suggest that slow and fast theta oscillations have distinct functional roles in episodic memory retrieval, with slow theta oscillations being related to processes of recollection and conscious awareness, and fast theta oscillations being linked to processes of interference and interference resolution.
大脑θ频段（3-8Hz）的脑电波震荡被证明与人类情景记忆的提取密切相关。先前的研究报告了皮质θ功率与提取成功率之间的正相关和负相关关系。本研究检验了这样一个假设，即在传统θ频带边缘的慢θ和快θ振荡与提取成功率呈不同的关系。当健康的人类参与者执行提示回忆情景记忆任务时，记录了头皮 EEG。在检索时，根据项目是否被回忆以及在测试中的输出位置，检查了慢（约 3Hz）和快（约 7Hz）θ振荡。由于干扰水平的增加，回想成功通常会随着输出位置的增加而下降。结果表明，慢θ功率与提取成功率呈正相关，而快θ功率与提取成功率呈负相关。慢θ和快θ振荡的同时出现的正性和负性情景记忆效应在时间和空间上是可分离的，在头皮上显示出不同的时程和不同的空间位置。此外，快θ功率从早期输出位置增加到晚期输出位置，而慢θ功率不受项目输出位置的影响。结合先前的工作，结果表明，慢θ和快θ振荡在情景记忆提取中具有不同的功能作用，慢θ振荡与再认和意识过程有关，而快θ振荡与干扰和干扰解决过程有关。
