S: 1 MEG demonstrated high redundancy in the original signal set. Most of the signal energy could be compressed in the first 30 principal components.

• 脑磁图信号有较高的冗余度,信号能量的绝大部分集中在前30个主成分中,从前30个主成分中抽取干扰源和诱发响应活动源。