Theta oscillations in human cortex during a working-memory task: Evidence for local generators
Theta oscillations in human cortex during a working-memory task: Evidence for local generators
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DOI：
10.1152/jn.00409.2005
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发表时间：
2006-03-01
影响因子：
2.5
通讯作者：
Kahana, MJ
中科院分区：
文献类型：
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作者：
Raghavachari, S;Lisman, JE;Kahana, MJ
皮层θ波在感觉加工和记忆中显得很重要。脑内电极记录为研究认知任务期间的这种振荡提供了一种高空间分辨率的方法。最近的研究揭示了工作记忆任务可以控制θ波范围（4 - 12 Hz）振荡的位置：θ波功率在任务开始时增加，并持续到任务抵消。使用现在已经收集的大数据集（10名参与者/ 619个记录位点），我们有足够的采样来确定这些门控位点在皮层中的分布以及它们是如何同步的。枕/顶叶皮质（45/157）和颞叶皮质（23/280）的大部分部位被任务门控。令人惊讶的是，这方面的工作记忆功能在额叶皮层中几乎不存在（2/182）。相干测度用于分析振荡的同步性。我们怀疑，由于工作记忆任务对门控位点的协调调节，它们会有同步的θ波振荡。我们发现，虽然附近的门控位点（< 20 mm）经常但并不总是相干，但远处的门控位点几乎从不相干。我们的结果表明，皮层θ的产生存在局部机制。
Cortical theta appears important in sensory processing and memory. Intracanial electrode recordings provide a high spatial resolution method for studying such oscillations during cognitive tasks. Recent work revealed sites at which oscillations in the theta range ( 4 - 12 Hz) could be gated by a working-memory task: theta power was increased at task onset and continued until task offset. Using a large data set that has now been collected ( 10 participants/ 619 recording sites), we have sufficient sampling to determine how these gated sites are distributed in the cortex and how they are synchronized. A substantial fraction of sites in occipital/parietal (45/157) and temporal (23/280) cortices were gated by the task. Surprisingly, this aspect of working-memory function was virtually absent in frontal cortex (2/182). Coherence measures were used to analyze the synchronization of oscillations. We suspected that because of their coordinate regulation by the working-memory task, gated sites would have synchronized theta oscillations. We found that, whereas nearby gated sites ( < 20 mm) were often but not always coherent, distant gated sites were almost never coherent. Our results imply that there are local mechanisms for the generation of cortical theta.