Understanding Parkinson’s Disease
- Harvey Zhou
- Jan 23
- 3 min read
TL;DR: Parkinson’s disease is a brain disorder that affects movement, balance, and posture, causing tremors, stiffness, and slow movements. Symptoms can be managed with medications like Levodopa or procedures such as deep-brain stimulation, but there is currently no cure. Ongoing research into brain function aims to develop better treatments.
Key Terms
Basal ganglia: The part of the brain that controls movement and coordination.
Dopamine: A brain chemical that helps control movement and motivation.
Deep-brain stimulation: A surgery where doctors put electrodes in the brain to reduce PD symptoms.
Levodopa: A dopamine replacement agent used to treat Parkinson’s Disease.
Substantia nigra: Located in the basal ganglia, it produces dopamine.
Bradykinesia: The medical term for very slow movements.
Postural instability: The medical term for issues regarding balance.
Akinetic/rigid: A type of Parkinson's disease that is mainly characterized by a lack of movement and stiffness.
MPTP: A chemical used to cause Parkinson’s disease symptoms in animal research.
Central vs. Peripheral Causes: Whether tremors originate in the brain (central) or muscles (peripheral).
Introduction
To begin understanding Parkinson’s, this article breaks down how changes within the brain can cause the disease. It highlights how Parkinson’s disease comes from the abnormal signals in the basal ganglia.
What Causes Parkinson’s?
Parkinson’s disease occurs when a brain cell in the substantia nigra dies. The substantia nigra produces dopamine, which controls movement. Dopamine is essential to the body because it allows us to move smoothly and with ease. As a result, people with Parkinson’s disease have trouble with simple tasks such as walking, writing, or talking.
Main Symptoms
The main symptoms of Parkinson’s include tremors, rigidity, bradykinesia, and postural instability.
There are two primary forms:
Tremor-dominant type: Shaking is the most noticeable symptom.
Akinetic/rigid type: Stiffness and slowness are more pronounced.
Although dopamine loss plays a central role, other neurotransmitters and brain circuits are also involved in the disease’s progression.
How the Brain Is Affected
Parkinson’s does not solely occur due to low dopamine levels. It affects the way the brain's circuits send signals. In normal conditions, the brain has a sequence of communications between different areas to help control movement. In Parkinson’s, these loops fire in wrong patterns and abnormal rhythms that make movements shaky and slow. Other parts of the brain, such as the cerebellum, may also be affected.
Central vs. Peripheral Causes
In the past, scientists debated whether tremors came from muscles or from the brain. Now we know that tremors mostly come from the brain, and the muscles are just reacting to the signals they receive.
Animal Studies
Scientists also study Parkinson’s disease in animals. One experiment uses MPTP, a chemical that damages the same brain cells that die in Parkinson’s, to simulate the neurodegenerative disease in animals. Monkeys that were given this chemical show symptoms that resemble human tremors, stiffness, and slowed movement. Doing these studies helps researchers test new treatments and understand the disease better.
Treatments
Currently, there is no cure for Parkinson’s disease, but treatments can help mitigate symptoms.
Levodopa is the most common medication, replenishing dopamine to restore smoother movement.
Deep-brain stimulation (DBS) involves implanting tiny wires that deliver electrical signals to the brain, helping reduce abnormal brain rhythms, tremors, and stiffness.
Although these treatments relieve symptoms, they do not stop the disease from progressing over time. Research continues to search for therapies that can slow or prevent cell loss in the brain.
Conclusion
Parkinson’s disease is caused by the malfunctioning of the basal ganglia, which produces the necessary dopamine for movement. This causes tremors, stiffness, slow movements, and balance problems. Treatments like medicine and surgery can help, but Parkinson’s disease still does not have a cure. Scientists continue to study the brain to find better treatments in the future.
The original research paper can be found at:
This paper was simplified by William Pu.
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