Mechano-encephalogram based on amorphous wire micro SI acceleration sensor

Time series reflecting human brain activities in mental and emotional states was detected using a sensitive micro acceleration sensor composed of a CoSiB magnetostrictive amorphous wire connected with a CMOS IC circuit with the resolution of about 0.1 Gal. A small sensor head of a glass specimen of 0.16 mm thick, 3 mm wide, and 15 mm long on which a CoSiB amorphous wire of 20 μm diameter and 5 mm long and an inertia mass of 0.1 gr are adhered was fixed on the center of forehead of a subject. Detected waveforms of the sensor output for several subjects with both eyelids closed were different from the conventional microvibration and were classified into four kinds representing the states at rest or lightly sleeping, passively stressed, actively stressed, and pleasant imaging. We named these signals as the mechano-encephalogram separating from the microvibration