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首页> 外文期刊>Progress in brain research >Upper alpha ERD and absolute power: their meaning for memory performance.
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Upper alpha ERD and absolute power: their meaning for memory performance.

机译：高阶ERD和绝对功率：它们对内存性能的含义。

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A variety of studies have shown that EEG alpha activity in the upper frequency range is associated with different types of cognitive processes, memory performance, perceptual performance and intelligence, but in strikingly different ways. For semantic memory performance we have found that resting or reference power is positively associated with performance, whereas during actual processing of the task, small power--reflected by a large extent of event-related desynchronization (ERD)--is related to good performance. We also have shown that the induction of large alpha reference power by neurofeedback training or repetitive transcranial magnetic stimulation (rTMS) at individual alpha frequency mimicked exactly the situation which is typical for good memory performance under normal situations: increased alpha reference power is associated with large ERD and good performance. Recent studies have demonstrated that this relationship holds true only for memory and not perceptual tasks that require the identification of simple visual stimuli under difficult conditions. In contrast to good memory performance, good perceptual performance is related to small pre-stimulus alpha power and a small ERD. We interpret this finding in terms of cortical inhibition vs. activation preceding task performance by assuming that large rhythmic alpha activity reflects inhibition. We assume that small reference alpha enhances perceptual performance because the cortex is activated and prepared to process the stimulus, whereas memory performance is enhanced if the cortex is deactivated before a task is performed because in typical memory tasks selective processing can start only after the to-be-remembered item or cue is presented. We also suggest that conflicting results about alpha ERD and the neural efficiency hypothesis (which assumes that highly intelligent exhibit a small ERD) can also be interpreted in terms of inhibition. Only if an intelligence test actually requires the activation of (semantic) memory, a large (because task specific) ERD can be observed. If other processing systems are required, the semantic memory system may even become suppressed, which is reflected by alpha event-related synchronization (ERS) or at least a largely decreased ERD.
机译：各种研究表明，高频率范围内的脑电图阿尔法活动与不同类型的认知过程，记忆表现，知觉表现和智力有关，但方式却截然不同。对于语义记忆性能，我们发现静止或参考功率与性能成正相关，而在实际处理任务期间，由大量事件相关的去同步（ERD）反映的小功率与良好性能有关。 。我们还显示，通过神经反馈训练或重复经颅磁刺激（rTMS）在单个alpha频率下感应大的alpha参考功率正好模仿了正常情况下良好记忆性能所特有的情况：增加的alpha参考功率与大的ERD和良好的性能。最近的研究表明，这种关系仅适用于记忆，而不适用于需要在困难条件下识别简单视觉刺激的知觉任务。与良好的记忆性能相比，良好的感知性能与较小的刺激前alpha功率和较小的ERD有关。我们通过假设大的节律性α活性反映了抑制作用，根据任务执行前的皮质抑制作用与激活作用来解释这一发现。我们假设小参考alpha会增强感知性能，因为皮质被激活并准备处理刺激，而如果皮质在执行任务之前被停用，则存储性能会增强，因为在典型的记忆任务中，选择性处理只能在目标执行之后才能开始。被记住的项目或提示。我们还建议，关于αERD和神经效率假设（假设高智能者表现出较小的ERD）的矛盾结果也可以用抑制来解释。仅当智力测验实际上需要激活（语义）记忆时，才能观察到大的（因为特定于任务的）ERD。如果需要其他处理系统，则语义存储系统甚至可能被抑制，这可以通过alpha事件相关的同步（ERS）或至少大大减少的ERD来体现。

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