Modulation of brain waves via auditory stimuli

The four main brain wave frequencies, alpha (8-12 Hz), beta (12-35 Hz), delta (0.5-4 Hz), and theta (4-8 Hz), dominate the brain at different times and dictate varying states of consciousness. We used musing to explore how it impacts the brain's frequencies. For this purpose, we used the electroencephalogram (EEG) device from BIOPAC with three different recording channels. The EEG electrodes were placed on the frontal, temporal, and parietal regions of the brain, which are associated with emotional processing, attention, and relaxation, respectively. The EEGs were recorded for 5 minutes before and after each musical condition to capture baseline and experimental brain wave activity. The music was presented through Apple Earpods at a comfortable, fixed volume. The time of day was between the hours of 12 and 6 p.m. so that circadian differences were not too distinct between trials. The subjects were both music experts and naïve subjects without any music background or training. Classical and rock music were the primary focus to study the effect on state of mind. As alpha waves define a relaxed state of mind, it was expected that classical music would cause these types of waves to take hold. Conversely, we predicted that rock music would cause the brain to exhibit beta waves, which characterize a state of wakefulness and alertness. Delta and theta waves are only exhibited in states of extreme relaxation and/or sleep, so we predicted they are less likely to be displayed during our experiment. The data were analyzed offline with the BIOPAC proprietary AcqKnowledge 5 software package. Among other measures, we explored the Fourier spectra and determined the ratio of brain wave power in different frequency bands.