Abstract: 1. An experiment was performed to investigate the correlation between α-blocking and mental activity (mental calculation) with the automatic analysing techniques etc. 166 subjects, 49 males and 117 females of 6 to 40 years of ages, were employed in the study. Subjects were specially selected, whose resting EEG's revealed a percent time α orθ(α) of more than 80. Results showed that there was a negative correlation between occipital α-blocking and mental activity.2. Automatic analysing techniques showed that during mental activity only 20% of the subjects were found to give diffusely α-blocking over the whole cortex and no subject was found to give only occipital α-blocking.3. Information processing of the occipital α-waves (driving response elicited by "threshold" photic stimulation) was not disturbed by mental calculation in 94.4% of the cases.4. Kappa waves of 6—8 c/sec, were observed in the frontal region during mental activity. These waves were not related to α-waves and eye-flutter movements.

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