Apparatus for measuring brain local activity

A computer-readable medium encoded with a computer program for measuring a brain local activity, the program when executed by a computer causes the computer to perform a method comprising:

• measuring scalp potentials of a subject from a plurality of sensors mounted on a head of the subject;
• and
• dividing, for each sensor, a predetermined frequency bandwidth wider than a frequency bandwidth of alpha waves of the scalp potentials measured by a plurality of sensors mounted on a head of a subject into a predetermined number of frequency banks each having a fixed frequency bandwidth, dividing, for each sensor, data of each divided frequency bank into segments of a predetermined duration on a time axis, determining, for each sensor, a Z-score of the subject from a first mean value, for each frequency bank, of normalized power variances determined for the segments and a second mean value, for each frequency bank, of normalized power variances predetermined in the same manner as the first mean value for a predetermined normal person group and a standard deviation of the normalized power variances in the group, and mapping on a brain surface for each sensor a mean value of the Z-scores determined over all of the frequency banks.