Millions of people in the United States are suffering from substance use disorder. Approximately 60,000 people nationwide are diagnosed with Parkinson’s disease each year. A Brown University undergraduate student is on a mission to understand the link between substance use disorder and Parkinson’s disease in an attempt to meet the country’s growing health care needs.
Priya Bhanot, a neuroscience concentrator, is studying new treatment therapies in addiction, a disorder characterized by its resistance to treatment, through the lens of Parkinson’s disease, a progressive nervous system disorder that affects movement.
Bhanot is a member of Brown’s Lee Lab, a neuroengineering lab affiliated with the Carney Institute for Brain Science where she is helping to develop neural prostheses that can remotely stimulate neurons using laser technology. Outside of the lab, Bhanot is developing her own neurotechnology proposal. She took a break from her research to discuss how she hopes to combine neuroscience, electrical engineering and physics to understand the link between addiction and Parkinson’s disease, as well as the neural basis of substance abuse progression.
Q: How did you become interested in studying dopaminergic motivation in addiction and Parkinson’s disease?
After taking the course NEUR1530: Communication in the Brain, I became fascinated by the vast networks of neural activity in the brain and how these systems produce complex thoughts and behaviors. I was particularly interested in the dopamine diffuse modulatory system of the brain and how its dysregulation can cause everything — from substance abuse to Parkinson's disease to schizophrenia. Because they present so differently, I never really considered how similar they may be. As I looked more deeply into the disorders, I became equally fascinated by how little was known about the dopamine pathways themselves. One of my peers, Eve Glenn, and I worked together on a final project studying these connections in more detail. This work was the inspiration for my independent research on how neurotechnology and neural implants can be used in substance use disorder treatment.
Although neuroscience has made exponential progress, very few aspects of the nervous system are completely understood. The dopamine diffuse modulatory systems are no exception, so I found it really exciting that I could analyze the intersection of all three fields and perhaps find something new in their juxtaposition. Ever since working in Professor Jonghwan Lee’s lab, I have also fostered a love of neuroengineering. New innovations are allowing us to learn more and more about the brain, its disorders and ways to treat it. I have taken courses studying this interdisciplinary field in more detail, and I am in the process of applying for an independent concentration at this intersection.
Q: Tell us about your research project investigating translational neurotechnology in addiction and Parkinson’s disease.
Substance abuse and Parkinson’s disease are both dopaminergic disorders affected by motivational dysregulation. Dopamine is a neurotransmitter that controls a host of complex behaviors, such as reward, motivation and voluntary movement. There are three main sites of dopamine production in the brain: the ventral tegmental area, substantia nigra and hypothalamus region of the brain.
Substance use disorder is categorized by overstimulation of the ventral tegmental area from repeated drug use, and resultant neuroplasticity that makes the behavior more likely to reoccur. Patients are often unable to resist the urge to use, despite understanding the negative impacts of their behavior on their health, relationships and general wellness.
Parkinson's disease, on the other hand, involves a degeneration of dopamine neurons in the substantia nigra that disrupts the rest of the basal ganglia loop that controls voluntary movement. Parkinson's patients often experience tremors, rigidity or a general inability to regulate their movements.
My research explores exactly how these impulse control disorders come to be and how they relate behaviorally and physiologically to substance abuse patients. Deep brain stimulation is the most common surgical treatment for Parkinson’s disease, and because of the neural dopamine link between the two disorders, I hope to translate this tool in substance abuse cases. Research has found that certain types of stimulation may affect neuroplasticity, which could potentially mitigate the effects of repeated drug use.
Q: What do you personally find most surprising, exciting or important about this work?
The link between Parkinson's disease and substance abuse is newly emerging, and each of the disorders themselves are far from being well understood. As a student, I find it super exciting that I can potentially add something new to the field, just by pursuing an in-depth exploration of the work that has already been established. Most importantly, I feel like my work has purpose.
As the tools available to neuroscientists evolve and more information about the brain as a whole is gained, we come closer to tackling disorders like substance abuse. In the process of writing a literature review on this topic — and in the independent research I have conducted since its inception — I have already begun to explore the state-of-the-art technology being used in Parkinson's research and how it may be applied to addiction cases because of their shared neural link.
Q: What potential applications might this research hold?
Deep brain stimulation (DBS) artificially stimulates the subthalamic nucleus and restores function of the nigrostriatal pathway for voluntary movement. Since Parkinson's disease involves direct dopaminergic neuron degeneration and substance abuse involves synaptic remodeling, the link in this therapeutic approach is not so overt. However, evidence suggests that theta frequency stimulation can actually reverse long-term potentiation (a persistent strengthening of synapses based on recent patterns of activity) within the brain, which is how repeated drug use is able to hijack the mesocorticolimbic pathway.
I believe that advancements such as closed-loop DBS, which are currently being explored in Parkinson's patients, may provide a hopeful avenue for substance abuse treatment. Closed-loop DBS involves a sensor implanted along with the electrode, so that it may record physiological or symptomatic parameters and respond appropriately to fluctuations in the disease. This form would allow for personalized treatment, fewer surgeries and more efficacy, as has been proven already in Parkinson's patients.
Non-invasive versions of these technologies are also being developed for Parkinson's patients, so by understanding the link between the two disorders, the functioning and dysregulated pathway in the brain, and the neural basis of substance abuse progression, these therapies could potentially be applied to both.
Q: Why did you decide to pursue a neuroscience degree at Brown?
The brain has fascinated me since before I understood what a neuron even was. In high school, I wondered how my entire reality — my connections with objects, people and ideas — are filtered and constructed by one vital organ. The parts of me that make me who I am and the parts of other people that make them special to me are all controlled by a hub of electric signals and ion gradients. Even though we’ve found a way to visit the moon and rearrange subatomic particles, we know relatively little about the networks of cells that dictate our sense of the world around us.
From research tools to discoveries about synaptic function, every level of this field provides an opportunity for research and exploration. As the home of BrainGate and the Carney Institute for Brain Science, Brown has always felt like the perfect place to pursue my passions. It is clear from my professors, lab mentors and peers that Brown believes in the ability to effect change, even as an undergraduate. After graduation, I hope to pursue my passion for neurotechnology in medical school and to one day treat patients as a neurosurgeon.