Brain music (2010.10.29)

This piece was derived from the electrical signals recorded during a sleep study that I underwent on 12 April 2010. The six hours of the study have been condensed into an interval of between 1-2 minutes in each case. (The original data was sampled at 256 Hz or 128 Hz, and the sound files were encoded at 44.1 kHz.) The first segment corresponds to the PNOSE channel (nasal prong pressure), a measure of airflow. Regular fluctuations in pressure correspond to a tone whose intensity changes with the amplitude of pressure variations (i.e., this tone increases in pitch when I was breathing faster, and increases in volume when I was breathing harder). The second segment derives from the encephalogram proper: from the electrodes C4-M1. Fleeting pure tones correspond to moments when the digital recorder was not measuring a signal, otherwise indicated by silence (e.g., as when the recorder was unplugged after I rolled over, which accounts for a long pause in each channel). Load outbursts correspond to moments when I wakened and fell back to sleep. The two long periods of "chirping" or "raindrop" sounds correspond to REM sleep. (The first episode begins about 41 seconds into the second segment.) Note that the outbursts that punctuate the calmer, deep sleep stages are very regular. The final segment is derived from the channel Thor (Thoracic Motion), a measure of thorax movements. This motion is apparently highly regular during sound sleep (breathing), and becomes irregular in light sleep or wakefulness. The result was synthesized using software that I developed in Python. -Oijo Baphuacs

brain-music.mp3

Brain music by Oijo Baphuacs is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.