The Parkinson's Brain

The brain is the most complex known structure in the universe. It weighs about 3 pounds and is mostly made up of billions of neurons and glia cells. Glia cells protect neurons by surrounding them and holding them in place, supply neurons with oxygen and nutrients, insulate neurons from each other, and destroy and remove dead neurons. Neurons transmit electrochemical signals to other brain cells, muscles, and gland cells, and control all muscle movement. 

Parkinson's disease occurs when dopamine producing neurons located mostly in the substantia nigra, an area of the brain that controls movement, become impaired or die. Normally, these neurons produce dopamine, an important brain chemical. When they die or become impaired, they produce less dopamine which causes the Parkinson’s related movement symptoms of tremors, rigidity, slowness of movement, and postural instability. Some areas of the brain have demonstrated the ability to grow new cells but not the dopamine producing cells of the brain. Scientists still do not know what causes cells that produce dopamine to die or fully understand how PD affects the brain.

PWP also lose the nerve endings that produce norepinephrine, the main chemical messenger of the sympathetic nervous system, which controls many automatic functions of the body such as heart rate and blood pressure. The loss of norepinephrine causes some of the non-movement symptoms of PD such as fatigue, irregular blood pressure, decreased movement of food through the digestive tract, and is important in preventing sudden drops in blood pressure when a person stands up. Recent research found that norepinephrine may help slow brain decline leading to dementia. Norepinephrine is released when the brain feels engaged, leading researchers to encourage challenging the brain with complex activities that exercise the brain.

The brain is so important and so smart that it developed a way to protect itself. The blood brain barrier was discovered in the 19th century when experiments revealed that dye injected into the bloodstream colored all of the body’s organs except the brain and spinal cord. When the dye was injected into the spinal fluid, only the brain and spinal cord were affected. The blood-brain barrier is made up of special, tightly bound cells that keep the brain safe and stable by allowing oxygen and nutrients to pass through but preventing toxins, pathogens, and other harmful substances from entering the brain through the bloodstream.

Parkinson's disease dementia is a decline in memory, thinking, and reasoning that develops in many PWP. Many brain cells of people with Parkinson's contain Lewy Bodies, unusual clumps of the protein alpha synuclein. Researchers are trying to better understand alpha synuclein and the impact it has on Parkinson’s disease and Lewy Body dementia. They are looking for ways to prevent the formation of alpha synuclein in the brain as well as ways to dissolve it once formed. Dementia with Lewy Bodies is the second most common type of neurodegenerative dementia after Alzheimer's disease.

The brain continues to grow, develop, and learn throughout life so remember what the Door Mouse said, feed your head. Nourish your brain and life with mental stimulation, physical exercise, and a healthy diet.