Appearance of frontal midline theta rhythm and personality traits.

The distinct theta rhythm in the frontal midline area during a performance of mental tasks has been called Fm theta. However, Fm theta shows individual differences in its appearance. The relationship between the appearance of Fm theta and the subject personality was investigated in the present study. Forty male university students performed an arithmetic addition test for 5 min daily during three consecutive days and their EEGs were recorded during the test. They also completed the Maudsley Personality Inventory (MPI) and the Taylor Manifest Anxiety Scale (MAS) after the EEG recording on the last day. The subjects who obtained low scores on the anxiety scale of MAS, high scores on the extraversion scale of MPI and low scores on the neuroticism scale of MPI showed larger amounts of Fm theta. On the other hand, those subjects who showed high scores on the anxiety scale, low scores on the extraversion scale and high scores on the neuroticism scale showed smaller amounts of Fm theta or none. These results suggest that the appearance of Fm theta is closely related to the subject personality traits.