This project aimed to study the impact of varying sound frequencies on learning without correlation to emotion. Previous research has shown that music improves learning ability, providing sufficient evidence of its positive i mpact on neural plasticity. However, it was hypothesized that the effect of the music was correlated to emotion and memories. This study closed that gap by studying the impact of pure tone frequencies on a model organism unaffected by emotion. The model organism, C. Elegans, was put through a chemotaxis assay as a paradigm for learning. One group was played the frequencies during and after the learning process. Other groups were played frequencies only during the learning process, only after the learning process, or not at all. The C. Elegans had more preference for the chemical attractant when 1kHz frequencies were played. This finding establishes that organisms’ brains respond and adapt to sound stimuli alone. Moreover, it opens the idea of manipulating sound to impact neural plasticity. These findings justify researchers studying the impact of sound on a neuronal level. With this, possible non-invasive interventions for neural plasticity-related mental illnesses, including Schizophrenia and Autism Spectrum Disorder, can be found.

The human body sends signals to and from various body parts to respond to external stimuli. When this occurs, sense organs notify neurons to fire, allowing electrical signals to pass through them. Each neuron receives the electrical impulse through their dendrites and releases them through their axons. The synapse, the space between the dendrite of one neuron and the axons of another, allows these electrical impulses to be passed between neurons (Barker, 2023). However, synapses may become unnecessary to function if the neural pathway is not used very often, resulting in synaptic pruning. Synaptic pruning is the process of removing unneeded synapses in the brain to open more space for learning. This process occurs in the decision-making part of the brain, the pre-frontal cortex (Carey, 2016). This process allows brain development and increases brain plasticity – its ability to change and adapt. Research has shown that synaptic pruning increases the brain's efficiency (Sandoval, 2015). Schizophrenia is a mental illness causing hallucinations and delusions. Research has shown that schizophrenia is linked to the increased expression of a particular gene that increases synaptic pruning (Carey, 2017). Schizophrenia is one among several mental illnesses impacted by the brain’s plasticity. Others include autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) (Problems with ‘pruning’ brain connections linked to adolescent mental health disorders, 2023). However, the brain’s plasticity is also impacted by music. Previous research has shown that participating in music creation affects the brain's white and gray matter. Musicians showed increased gray matter in motor and auditory cerebral areas (Rodrigues et al., 2010). Moreover, a study performed at the University of Toronto played music to fourteen Alzheimer patients – six of whom were musicians, and eight were not. The patient's brains were scanned before and after listening to music one hour a day for three weeks. The music also varied; some music had sentimental value, and other music was new. This study found that music with personal connection impacted deep connections in the pre-frontal cortex. Additionally, structural differences were found between musicians and non-musicians due to music listening. Various studies show that musical training and listening to music impact neuroplasticity. However, it is unclear if this is only due to memories and mood. This study aims to close that gap by studying the model organism, C. Elegans, as they respond purely to the stimuli. Moreover, the study will establish any connections between sound and learning. The goal of this project is to study the impact of varying pure tone frequencies on neural plasticity. This study will be performed using a chemotaxis assay as a paradigm for learning. In this assay, the C. Elegans will learn to associate the smell of isoamyl alcohol with food. Their memory will be tested by observing how many worms move towards isoamyl alcohol rather than the control chemical. Pure tone frequencies will be played at varying frequencies during and after the learning process to find if it improves memory. The chemotaxis index will be calculated to quantify results. Findings may be used to justify more research in using music as a mitigation strategy for schizophrenia, ADHD, and ASD. Overall, this proposal may provide insight into the crucial functionalities of the brain. Further research may include observing the impact of music on neuronal activity and synapses. Additionally, there can be narrower research into the optimal frequencies to invoke or decrease changes in neural plasticity.

The worms were put through a chemotaxis assay for short-term memory, per Kauffman et al., 2011. In this assay, a group of worms were trained to associate food with the chemical odorant and attractant, isoamyl alcohol. Therefore, when placed on a plate with the odorant, they would show preference for it by moving towards it. This was done by starving them in M9 buffer for 1 hour, conditioning them on a seeded plate with Isoamyl Alchohol on the lid for 1 hour, and counting worms after incubating them on the chemotaxis plate for 1 hour. The process was modified by playing frequencies during and after the training period to observe any changes in associative memory due to the presence of frequencies. This allowed me to measure the impact of sound on memory.