Electroencephalogram activation apparatus

1. An electroencephalogram activation apparatus, comprising:

an electroencephalogram acquisition unit configured to acquire brain waves of a user;

an electrical stimulation unit configured to apply transcranial electrical stimulation to a scalp of the user; and

a control unit configured to control the electrical stimulation unit based on the brain waves acquired by the electroencephalogram acquisition unit,

wherein,

the electrical stimulation unit applies transcranial electrical stimulation at a given frequency to the scalp of the user, and

the control unit controls the electrical stimulation unit in accordance with potential density in a frequency range of a brain wave activated by the transcranial electrical stimulation at the given frequency.

2. The electroencephalogram activation apparatus according to claim 1 , wherein the control unit judges one of a plurality of sleep stages of the user based on a characteristic waveform that appears in the brain waves, and controls the electrical stimulation unit in accordance with the sleep stage.

3. The electroencephalogram activation apparatus according to claim 2 , wherein the control unit applies the transcranial electrical stimulation to the electrical stimulation unit when the sleep stage is Stage 2, and does not apply the transcranial electrical stimulation to the electrical stimulation unit when the sleep stage is other than Stage 2.

4. The electroencephalogram activation apparatus according to claim 1 , wherein:

(1) the electroencephalogram acquisition unit includes

(a) a first electrode to be held in contact with the scalp of the user,

(b) a first amplifier having an input terminal to which the first electrode is connected, and

(c) a second electrode connected to a ground potential and to be held in contact with a head of the user,

(2) the electrical stimulation unit includes

(a) a voltage source,

(b) a resistor connected to the voltage source,

(c) a second amplifier having an inverting input terminal to which the resistor is connected and a non-inverting input terminal to which the ground potential is connected, and

(d) a third electrode connected to an output terminal of the second amplifier and to be held in contact with the head of the user, and

(3) the control unit is connected to an output terminal of the first amplifier and controls the electrical stimulation unit based on a brain wave corresponding to a potential difference between an output of the first amplifier and the ground potential.

5. The electroencephalogram activation apparatus according to claim 1 , wherein:

(1) the electroencephalogram acquisition unit includes

(a) a first electrode to be held in contact with the scalp of the user,

(b) an amplifier having an input terminal to which the first electrode is connected, and

(c) a second electrode connected to a ground potential and to be held in contact with a head of the user,

(2) the electrical stimulation unit includes

(a) an electric current source,

(b) a third electrode connected to the electric current source and to be held in contact with the scalp of the user, and

(c) a fourth electrode connected to the electric current source and to be held in contact with the scalp of the user, and

(3) the control unit is connected to an output terminal of the amplifier and controls the electrical stimulation unit based on a brain wave corresponding to a potential difference between an output of the amplifier and the ground potential.

6. The electroencephalogram activation apparatus according to claim 1 , wherein:

the electrical stimulation unit applies slow oscillation as the transcranial electrical stimulation, and

the control unit controls the electrical stimulation unit based on potential density of a brain wave within a frequency range of a θ wave.

7. The electroencephalogram activation apparatus according to claim 1 , wherein the electroencephalogram activation apparatus is configured as a headgear that can be worn by the user.

8. The electroencephalogram activation apparatus according to claim 7 , wherein the electroencephalogram activation apparatus further comprises a support unit configured to fix the electroencephalogram activation apparatus to a head of the user.

9. The electroencephalogram activation apparatus according to claim 1 , wherein the electroencephalogram activation apparatus further comprises a wireless communication device configured to communicate with an external apparatus.

10. The electroencephalogram activation apparatus according to claim 1 , wherein the electroencephalogram activation apparatus further comprises a storage device.