Phase/amplitude reset and theta-gamma interaction in the human medial temporal lobe during a continuous word recognition memory task
Phase/amplitude reset and theta-gamma interaction in the human medial temporal lobe during a continuous word recognition memory task
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DOI：
10.1002/hipo.20117
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发表时间：
2005-01-01
期刊：
影响因子：
3.5
通讯作者：
Fernández, G
中科院分区：
文献类型：
--
作者：
Mormann, F;Fell, J;Fernández, G
我们分析了12例癫痫患者在连续单词识别范式中的颅内脑电图（EEG）记录，对比了正确识别重复单词（命中）和正确识别新词（正确拒绝）的试验。利用基于小波的分析，我们研究了不同频段的功率变化和相位聚类对平均事件相关电位（ERPs）的影响。此外，我们还分析了不同振荡的实际平均相位。我们的分析得出了以下结果：(1)功率变化只对ERP的后期成分（bb0 ~ 400ms）有显著影响。(2)早期ERP成分是在刺激开始后约190ms的持续振荡活动中产生的与刺激相关的宽带相位和振幅重置，不仅涉及θ波段，而且涉及θ波段。(3)相位和幅度重置发生在相位携带增加的时期，随着时间的推移，所有涉及的频率持续了大约两个振荡周期，正确拒绝比命中更明显。在命中和正确拒绝中都观察到宽带相位和振幅重置，因此，似乎不支持特定的认知功能，而是作为涉及该记忆任务的过程的一般促进因素。进一步分析不同频带振荡和功率变化之间的同步性，揭示了携带θ波周期对伽马活动的任务依赖性调制，这一机制可能分别与鼻皮质和海马的记忆编码和检索有关。(c) 2005 Wiley-Liss, Inc。
We analyzed intracranial electroencephalographic (EEG) recordings from the medial temporal lobes of 12 epilepsy patients during a continuous word recognition paradigm, contrasting trials of correctly recognized repeated words (hits) and correctly identified new words (correct rejections). Using a wavelet-based analysis, we investigated how power changes and phase clustering in different frequency bands contribute to the averaged event-related potentials (ERPs). In addition, we analyzed the actual mean phases of the different oscillations. Our analyses yielded the following results: (1) power changes contributed significantly only to the late components of the ERPs (> 400 ms) (2) earlier ERP components were produced by a stimulus-related broad-band phase and amplitude reset of ongoing oscillatory activity about 190 ms after stimulus onset that involved not only the theta band, but also covered alpha and lower beta band frequencies (3) phase and amplitude reset occurred during an epoch of increased phase entrainment over time that lasted for about two oscillation periods for all involved frequencies and was more pronounced for correct rejections than for hits. The broad-band phase and amplitude reset was observed for both hits and correct rejections, and therefore, did not appear to support a specific cognitive function, but rather to act as a general facilitating factor for the processes involved in this memory task. Further analyses of synchronization between oscillations and power changes in different frequency bands revealed a task-dependent modulation of gamma activity by the entrained theta cycle, a mechanism potentially related to memory encoding and retrieval in the rhinal cortex and hippocampus, respectively. (c) 2005 Wiley-Liss, Inc.