 Sound and brain >> EEG>> 
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脳波 -EGG-Ultra faint current always flows in the human brain. A method of recording electric activity occurring in the brain with electrodes on the scalp. This is "EEG". In all areas in the brain, countless currents are constantly occurring in various directions.There is a similar thing called "magnetoencephalogram", unlike brain waves, it is not a current but a magnetic force. Therefore, it is measured. (Essentially the same as EEG) There are two types of electroencephalograms, spontaneous electroencephalogram and evoked electroencephalogram. Spontaneous brain waves are brain waves that are always living even without doing anything, and brain waves that are constantly evoked are electroencephalograms generated by external stimulation. Mnemonic name varies depending on stimulus, in case of sound, it is called "auditory evoked potential". In other words, sound is transmitted to the brain by this, and it is structured to hear it! EEG historyIf you summarize the past history of brain waves in an easy-to-understand manner it
will be as follows.
1875 Richard Carton (UK)：Reported thatelectric phenomena are observed in the brains of animals. 1929 Psychiatrist Hans Berger (Germany)：Report on electric phenomena for the first human being. 1935 Edgar Adrian：The alpha wave is named "Bergerism". 1936 Masashi Matsudaira (Associate Professor, Tohoku Imperial University)：Trial production of brain wave amplifier. 1942 Sachi Katsunuma (Professor, Nagoya Imperial University)：I proposed a nickname "EEG". 1992 USA and Germany：Development of electroencephalogram monitor About the kind of electroencephalogramFirst, I will talk about basic rhythm. Fundamental rhythm is a specific brain wave activity that creates many parts of brain waves, and it changes with awakening degree, age, drugs, and there are many pathological conditions that show abnormalities. pathological conditions that show abnormalities. In addition, the wave differs depending on Hz (unit of sound), and its name is as follows. Delta wave: 1 to 3 Hz Theta wave: 4 to 7 Hz Alpha wave: 8 to 13 Hz Beta wave: 14 to Hz Generally, in healthy subjects, alpha waves appear more often around the back of the head in rest, closed eyes and arousal states. At restful arousal closed eyes for healthy adults, the alpha wave appearing in the occipital region dominates the basic rhythm. A waveform with a slower frequency than the alpha wave is referred to as a slow wave, and a waveform with an earlier frequency is referred to as a fast wave. |
