The Research Of Scale-free Brainwave Music

The electroencephalogram (EEG) is the general performance of the mass of thebrain neurons, and it involves the wealth of neural information. Music is the product ofhuman brain intellectual activity, and affects the human by both physiological andpsychological way.The relation between brain and music is always a hot issue in theneuroscience and psychology research fields. It is important to investigate that how totranslate EEG signals into music and analyze the generated music. It is helpful for thediscussion of the relation of brain and music.Thisthesis firstly investigated the mathematic and physical properties of both EEGsignals and music, and then proposed a series of method of brainwave music translationbased on the scale-free characters followed by EEG and music. The following studiesare presented and discussed:1. Based on the scale-free property of the EEG amplitude and musical pitch, weproposed the scale-free brain music method for single EEG channel. According to thewave chanracters, the brainwave was labeled as “Event”; an event was been translatedinto a note. The length of the event was mapped to the lasting time of the note; theamplitude was mapped to the pitch; and the average power was mapped to the volume.The real EEG signals were used for music generation. The results showed that the brainmusic of different mental states can be distigushed easily. Compared to another methodwhich baced on the arousal level, the scale-free method reflected the details of thewaveform trustily, and reserved the scale-free properties of the originalsignals. The realtime brain music system was developed, and can be used for real time monitoring andbio-feedback.2. Based on the scale-free brainwave music method for single channel, weproposed a method for translating the two channels EEG signals into an ensemble. First,the signals from the left and right hemispheres were translated into MIDI sequencesrespectively; second, modulated the sequences according to the Chinese pentatonicscale and the Western diatonic scale. The results showed that the pitch of the music wasscale free, and scaling exponents of the different brain states with the two tonality scales were significant different. The intervals of the music with pentatonic scale soundedmore consonant, and the distribution of the harmony intervals were closer to1. Inaddition, the differences of the music from sleep states were more significant after thepentationic scale modulation.3. By analyzing lots of music works, we found that the oscillation of theconsonance of musical intervals was scale free. And such properties can reflect thepreference of musicians. Networks based on the consonance indicatedtheinheritance andinfluence of the musicians. And then we proposed the brainwave music method whichbased on the scale-free oscillation. The signals from two channels were translated intoMIDI sequences respectively, and the EEG phase synchronization index (PSI) wasutilized to modulate the interval consonance and the volume. When the PSI was high,the music sounded consonant and louder, while the PSI was low, the music soundedinconsonant and the volume was low. Analyzed the generated music of eyes closed andeyes open, we found that the scaling exponents of the modulated music were closer tothe original EEG signals. The method can express the dynamic varieties of thecollaboration of the brain regions in an artistic way.4. The power spectral of the musical rhythm was analyzed and discussed. Severalgenres of the Chinese music were selected, including the archaic music, the children’smusic, the popular music and the local operas. The results showed that the spectral ofmusical rhythm was scale free. And then a method for brainwave quartet was proposed.The signals from all the channels were translated into MIDI sequences respectively, andthe artistic filters were designed by imitating the creation of musicians. The notes whichwere in accord with the tonality and rhythm were preserved, and became the quartet.The results showed that the quartet was morerhythmical, musical and rich than thesingle channel music. Furthermore, the scaling exponents of brainwave quartet werecloser to the original EEG, and were identified easily for different states.5. The scale-free brainwave music was utilized for the control of orthodontic pain.The subjects were put into three groups after initial archwire placement. The brainwavemusic group was asked to listen to their brainwave music every day; the music wastranslated from the rest eyes-closed EEG recored before the archwire placement. Thecontrol group was no intervention. The cognitive behavioral therapy (CBT) group wasasked to follow the correspondinginstructions. The results showed that the brainwave music relieved the orthodontic pain. Compared to the control group and CBT group, thebrainwave group had lower points in the pain scale, and the connectivity of EEGcoherence network were better than the control group significantly, were little higherthan CBT group. The network parameters of brainwave music group were closer to thesmall-world network. It revealed that the brainwave music was effective in theorthodontic pain relief, and was little better than the popbehavioral therapy.