Welcome to 2 minute neuroscience, where I explain neuroscience topics in 2 minutes or
In this installment I will discuss Parkinson’s disease.
Parkinson’s disease is considered a neurodegenerative disease because it involves the degeneration
and death of neurons.
It is most frequently seen in adults over the age of 50.
The most recognizable symptoms of Parkinson’s initially are movement-related and generally
involve a tremor that is worse when a person is at rest, bradykinesia, which is slowness
of movement, rigidity, and postural impairment.
Parkinson’s patients also often experience non-motor symptoms like cognitive impairment
or psychiatric symptoms.
The causes of Parkinson’s are not fully understood, but a combination of genetic and
environmental factors is likely involved.
Parkinson’s patients have low levels of the neurotransmitter dopamine in the basal
ganglia, a group of structures involved with movement (among other functions).
These low dopamine levels in the basal ganglia are caused by the death of dopamine neurons
in a region of the basal ganglia called the substantia nigra.
The substantia nigra has high numbers of dopamine neurons, but by the end stages of Parkinson’s
patients have often lost more than half of the dopamine neurons in this region.
The most common treatment for Parkinson’s involves an attempt to restore depleted dopamine
levels in the basal ganglia.
Because dopamine does not cross the blood-brain barrier, dopamine cannot simply be administered
to a patient.
Instead, however, patients can be given a precursor to dopamine called L-DOPA.
L-DOPA can cross the blood-brain barrier and is used by the brain to synthesize more dopamine.
This can lead to improvement in the motor symptoms of Parkinson’s, but L-DOPA does
not halt the neurodegeneration that occurs in parkinson’s disease, and long-term use
of L-DOPA can cause a number of side effects, including movement-related problems.
So it is not a cure for the disease and other treatments are still being explored.