AUDITORY PSYCHOPHYSICS:

THE EFFECTS OF MUSIC & SOUND ON THE ADOLESCENT BRAIN

Lucas M.

Marin Academy Research Collaborative Program (MARC IR 2)

Past

In the 21st century, music is more pervasive than ever. It evidently plays a role in influencing our daily moods; however, we have only uncovered a fraction of the full extent to which music can impact our brains.

Although the effects of music on the brain have been tested for and documented in adult subjects, I encountered no studies that involved adolescent subjects in my review of the existing literature regarding auditory psychophysics. As teenagers are still learning how to regulate their emotions, and with music so pervasive in modern society, I was curious to explore how music and sound might impact adolescents and whether or not the effects would differ from adults.

PRESENT

I'm currently preparing for testing in the Fall. I am doing so by finalizing my decision on which alternative neural imaging technology I will select as a feasible alternative to EEG biofeedback machinery. I am also developing a list of criteria that subjects must fit in order to partake in the experiment along with consent forms that each participant must sign. Additionally, it is critical that I keep myself updated with new articles regarding auditory psychophysics that surface.

Electroencephalogram (EEG) Alternatives

For a student to gain use of professional equipment such as an fMRI scanner or EEG machine with functional neuro-imaging, it would require access to a laboratory that contains such equipment. This kind of access is improbable for three major reasons, the first being that the COVID-19 pandemic has greatly limited lab hours and halted outside accessibility to a significant extent. The second factor is affordability. If one were to purchase such professional equipment for personal use, would cost anywhere between $4,000 and $20,000 (Hutchison, 1994). The image to the left shows a few cheap, feasible alternatives to machinery like EEG Biofeedback setups. They also don't require professional supervision and are much more portable.

Neural Oscillations

Networked neurons fire synchronized action potentials in different patterns. The term neural oscillation refers to rhythmic patterns created by synchronized action potentials in the central nervous system (CNS). Neural oscillations, also called brain waves, are commonly separated into five predominant frequency bands (as shown in the figure above. The frequency spectrum is commonly associated with consciousness, with the brain displaying more amounts of consciousness as higher frequency oscillations are active.

Binaural Beats

Binaural beats are auditory phenomena that occur when two low-frequency sine waves (less than 1500 Hz) with slightly different frequencies are played in a patient's ears. When the two waves are played together, the difference between the two frequencies creates the third sound, in the form of a pulsing beat, appears. The frequency of this beat is the difference between the two sine wave frequencies, and in the existing literature that I’ve covered so far, networked neurons often mimic the pulse and apply it to the rate at which they fire. Binaural beats are often used in tandem with measurements of neural oscillatory activity as these synthetic pulses, if being played at the same frequency as any one of the five bands, can garner increases to their activity in the CNS.

Future

By early 2022, I will be in the middle of my experimental phase, testing how different audible stimuli affect striatal dopamine function and certain frequency bands of neural oscillations. Through the results of my experiment, I hope to contribute notable information to the collective understanding of how sound can affect the brain.

The auditory psychophysics field is one I'm extremely interested in and I hope to continue my studies in college.

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