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Audrey Murphy

Class of '20

       Hi! I'm Audrey Murphy, a senior at Laguna Blanca School. I applied to the STEM program because I have always been interested in science and wanted to extend my knowledge past what we learn in Biology, Chemistry, and Physics. There is a huge world of applied sciences and specialized fields to learn about, and this is exactly what Ms. Richard has given us the opportunity to familiarize ourselves with. 

       During my sophomore year, I became interested in sound waves and their medicinal applications. I realized through my research that in order to fully understand sound waves, I must also understand the brain. This prompted my application and consequent enrollment into St. Andrews University Psychology and Neuroscience summer program between my sophomore and junior year. Once I returned, I began research with The Jacobs Neuroendocrinology Lab at UCSB to discredit variability as a justification for the exclusion of women in neurobiological research. My research culminated in an end-of-year project dubbed "The Variability Project" summarized below! I am currently learning sign language to return to deaf research now with a foundation of neuroscience.

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THE SCIENCE OF SOUND

Interesting Links -

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Boy singing stops tourettes:

https://www.youtube.com/watch?v=skjfAhVa8L0

 

Soundwaves can stop brain diseases:

https://www.scientificamerican.com/article/sound-waves-can-heal-brain-disorders/

 

Surgery using soundwaves:

https://www.technologyreview.com/s/414429/brain-surgery-using-sound-waves/

 

Sound waves are currently being used in surgery using ultrasonic frequency and high-intensity focused ultrasound.

 

In short, surgeons and engineers use focused and intense sound waves with magnetic force to burn and destroy dead brain tissue with incredible accuracy -- without scalpels or radiation. 

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As our knowledge of sound waves and noise has advanced, so has our technology to utilize them. New studies have been conducted and medicinal applications have been performed with concentrated sound waves most have never thought possible before -- using sound waves in brain surgery on Parkinson's patients, using sound waves to administer drugs to the brain, and the affect singing has on Tourette's syndrome to name a few. The links to these articles can be found in the sources section of this article.

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According to the Technology Review, scientists have discovered a new approach to neurosurgery using simultaneous ultrasound and magnetic resonance imaging (MRI), allowing neurosurgeons to precisely eliminate small pieces of malfunctioning brain tissue without cutting the skin or opening the skull. This was first done in a preliminary study in Switzerland involving nine patients with chronic pain to conclude that the technology can be used safely in humans. The researchers now aim to test it in patients with other disorders, such as Parkinson’s disease. High-intensity focused ultrasound (HIFU) beams are directed onto a diseased tissue which is in turn heated and destroyed. So far, this medical practice has only been attempted in general surgery, such as tumors in the uterus. Surgeons are struggling to find ways to apply this strategy to the brain, whose skull absorbs energy from the wave and distorts it's path, making it very difficult to be precise. Many scientists hope sound waves could be the answer to administering chemotherapy to brain tumor patients using deep thermal lesions that surgeons would otherwise not be able to reach. 

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According to the Scientific American, Kullervo Hynynen, a medical physicist at Sunnybrook Research Institute in Toronto, has discovered a way to utilize sound waves when administering drugs to the brain directly. Scientists administer a drug followed by an injection of microscopic gas-filled bubbles. Patients then put on a cap on the focused sound waves in specific brain locations using HIFU (stated above). "The waves cause the bubbles to vibrate, temporarily forcing apart the cells of the blood-brain barrier and allowing the medication to infiltrate the brain." Hynynen and his team are currently testing whether they can use the method to deliver chemotherapy to patients with brain tumors.  

 

Furthermore, sound waves also have applications in Autism and its relationship to sound at a particulate level. An article in the Washington Post, written by Laura Sanders, reveals a possible correlation between Prenatal Ultrasounds and Autism in children. The study that the WP examined concluded almost no correlation between prenatal ultrasound and Autism, except for in one measure. Researchers found that during the first trimester, mothers who had children with autism had slightly deeper ultrasounds than women who had typically developing children and children with developmental delays. To clarify, Ultrasound depth measures the distance from the transducer paddle that emits the waves to the spot that’s being imaged. Although the study did not conclude anything wrong with ultrasounds that expectant mothers should worry about, it makes readers contemplate how technology could be disturbing our anatomy, unbeknownst to us. 

 

Immediately, I considered the different tests we conduct on ourselves to further our knowledge of our personal anatomy, and I immediately thought of X-rays and how we protect ourselves from their harmful radiation. We cover our bodies, or the specific part that is exposed to the radiation, with a lead blanket that has been proven to protect us. I am interested to know why we don’t take similar precautions with prenatal ultrasounds. Should there be a protection blanket to shield our unborn children from harmful ultrasound waves without impeding the necessary imaging? We may not be able to hear them, but our lack of brain reception does not mean the sound waves are not present. 

 

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I’m not sure how many studies have been conducted to reveal the effects of ultrasound on unborn babies, but I would like to do more research on the topic. In discussion with my classmates, I formed a hypothesis questioning the effect: We know that as we age our hearing worsens, and when we are young, our hearing is the best it will be. Could the process of vibratory hearing be exceptionally more advanced in unborn babies, and how could the intensity of an ultrasound alter the fetus' development?

"There is not one section of our brain that is solely responsible for our interpretation of sound"

"I like to think of sound waves as a disturbance of the immediate atmosphere at the particulate level "

Sound is measured in Hertz (Hz) and decibels (dB). The average human can hear noise as low as 0 dB and noise up to 85 dB. 85 dB and above cause pain and damage to our ears. To put it into perspective, fireworks are 140-145 dB, a lawnmower is 85-90 dB, and normal conversation is 50-65 dB, depending on how loud your friends are.

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Let’s delve into how our brain interprets sound. For example, how do we know if someone is angry or excited by just the sound waves we receive? Our brain works entirely by utilizing electricity, so everything we receive is turned into electric pulses to be processed in the brain. Sound waves are no exception. Once the wave interacts with the auditory nerve (see figure 1), the nerve sends electrical signals to different sections of the brain, for example the amygdala, where we process emotions and empathy.  

There is not one section of our brain that is solely responsible for our interpretation of sound. For example, when we hear our favorite part of a personally meaningful song, dopamine is released in the striatum, the ancient part of our brain that responds naturally to rewarding stimuli. Remember the opening to Don’t Stop Believin’ by Journey? The rich piano chords that prefix a song for the ages? The lyrics that bring you back to that night in college circa 1981 when you needed that one extra push to finish your term paper? Just by thinking of this song, your central cortex is firing with neurons to remember the feeling the song has repeatedly given you.

Let’s try an activity. Put your two index fingers together at the first (top) digit and move the two fingers against each other where you can see them. You can feel the grooves in your fingerprints, however you can’t hear anything. Now, keeping your index fingers together, raise your right hand until the backside of your hand is pushed against your ear, still moving your fingertips together. Can you hear a zipper sound? The zipper sound is the result of vibrations from the grooves in your fingerprints rubbing against each other creating a sound wave which then travels through your arm and ear canal, and interacts with your eardrum. From your eardrum, the soundwave then vibrates the eardrum and oscillates through the oval window. The auditory nerve accepts the wave and translates it into electric impulses which are then processed by your brain to cognitively identify the sound.

This same process occurs when we hear any sound, regardless of whether or not your arm acts as the medium for the waves to travel through. Music, everyday noises, and conversations are all understood this way, for each noise we hear is a form of a sound wave traveling through a medium. When sound waves are not traveling through our anatomy, they move air particles in a specific ways, should the medium be air. I like to think of sound waves as a disturbance of the immediate atmosphere at the particulate level. To clarify, sound waves cannot exist independently, they must distort a medium.

"We may not be able to hear them, but our lack of brain reception does not mean that the sound waves are not present"

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