Parkinson’s Disease: Neuroscience

This is the second post in the series of blogs I will write about Parkinson’s, to honor my grandmother, who passed away last week.

PD is a disease experts call “idiopathic”, which means “arising spontaneously” or “from an obscure or unknown cause”. However, there is some proof that in a (very) small amount of the patients there is a genetic component. This means that PD might be hereditary in some cases (which is a frightening thought).

Parkinson’s is neurological illness and to best explain what causes PD, I will have to throw somewhat difficult terms at you, but I hope it’s clear enough to follow.

The substantia nigra and the pars compacta

Within the substantia nigra, a part of the basal ganglia, a structure in the midbrain,  is where dopamine is produced. It plays a vital role in human behavior and cognition, voluntary movement, motivation, punishment and reward, sleep, mood, attention, working memory, and learning. If you remember my previous blog, you probably relate many of these functions with the symptoms of PD.

Let’s zoom in a little further. Within the substantia nigra, there is an area called the pars compacta. This is where Parkinson’s develops. PD is characterized by the death of neurons related to dopamine in the pars compacta. The cause of the death of these neurons is unknown, but there are some rather complex theories that still need proof to be verified (or falsified). However, the plasticity of the pars compacta is surprising:  symptoms of PD don’t appear until 50-80% of the neurons in the pars compacta have died.

The substantia nigra is also the place where schizophrenia develops. Contrasting to PD, schizophrenia is characterized by heightened levels of dopamine (although still controversy still surrounds this theory, there has been some proof to verify it).

As you can tell, a lot of research needs to be done still, to find what really causes PD.

A random fact: Dopamine is often called the “happy hormone” or “love hormone”. It’s actually not a hormone, but a neurotransmitter. If you’d read their definitions, the difference seems hard to detect. So, in short… A hormone is a chemical compound released by an endocrine gland (i.e. the thyroid gland) directly into the bloodstream so it can find its destination, which is usually some distance from it’s source. A neurotransmitter travels much less. It’s released in a nerve ending to carry a signal through the junction between cells called the synapse.

If you have any questions at all, please don’t hesitate to ask! Comments and other messages are always welcome, too, naturally.

The next blog will be about the medical management of Parkinson’s Disease, and what researchers are currently doing to find a cure for the illness. That post will also conclude this blog series!