Decreases in alpha synchronization are correlated with enhanced attention, whereas alpha increases are correlated with inattention. However, correlation is not causality, and synchronization may be a byproduct of attention rather than a cause. To test for a causal role of alpha synchrony in attention, we used MEG neurofeedback to train subjects to manipulate the ratio of alpha power over the left versus right parietal cortex. We found that a comparable alpha asymmetry developed over the visual cortex. The alpha training led to corresponding asymmetrical changes in visually evoked responses to probes presented in the two hemifields during training. Thus, reduced alpha was associated with enhanced sensory processing. Testing after training showed a persistent bias in attention in the expected directions. The results support the proposal that alpha synchrony plays a causal role in modulating attention and visual processing, and alpha training could be used for testing hypotheses about synchrony.

中文翻译：

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Alpha同步和空间注意力的神经反馈控制。

alpha同步的减少与注意力增强相关，而alpha的增加与注意力不足相关。但是，相关性不是因果关系，同步可能是注意力的副产品，而不是原因。为了测试阿尔法同步在注意力中的因果作用，我们使用MEG神经反馈训练受试者以控制左顶壁皮层与右顶叶皮层上的阿尔法功率之比。我们发现在视觉皮层上发展了可比的alpha不对称性。alpha训练导致在训练过程中对两个半场中显示的探针的视觉诱发响应发生相应的不对称变化。因此，降低的α与增强的感觉处理有关。训练后的测试显示，注意力在预期方向上持续存在偏见。