What is Alzheimer's Disease - defining some key terms

Everyone has heard of Alzheimer's Disease. Whether it is because someone you know has suffered from it, have read about it, or are trying to impress a lady with your knowledge of The Notebook (Admit it, gentlemen, we only pretend to enjoy that movie).

But, what exactly is this disorder? We will cover the diagnoses and underlying pathology in future posts. Today, we will focus on a definition of the disease, along with explaining a few key terms that are integral to all future posts.

So, let's get to those key terms. Now, all of you fall under two categories here -- 

1. If you are a neuroscientist, or have taken graduate level biology, most of this might seem redundant to you. But, I would appreciate you reading through this any way, to help critique my explanations and analogies. 

2. If you have always wondered what these terms meant, I hope I can shine a light on their meaning.

Neuron - These are cells in the brain. They are responsible for all your emotions and your memories.  Depending on where in the brain they are located (there are different brain regions responsible for different functions) or what type of neuron is present (there are different types), they contribute to why you think - "Ryan Gosling", every time you hear the word "dreamy". Or, you scrunch your nose, every time someone brings up yogurt (seriously guys, yogurt is disgusting). Neurons are the minions that facilitate everything you consider to be a feeling or a memory. 

In a certain part of the brain, called the Hippocampus, there are neurons that allow for the formation of new memories. During Alzheimer's Disease, this is one of the first regions to be affected. What does it mean to be affected? The neurons in this brain region die. Why is this relevant? Because, unlike cells in other parts of our body, neurons do not divide. Therefore, once a neuron dies, there will not be another one to replace it. And the relevance to memory? Well, theoretically, if you've lost a neuron relevant to a memory, you've lost that memory, or the ability to make a new memory. 

If the brain is an engine, and different areas of the brain represent different engine parts, neurons are the nuts and bolts that enable everything to work. 

Receptor - A gateway for communicating with neurons. Think of the cell as a fortress. A receptor is the draw bridge which allows communication with the fortress. Either by allowing a visitor in, or by relaying the messages of the visitor to the people inside the fortress.

Dementia - This is a loose term that is often misinterpreted. Dementia refers to a state in which normal brain function is impaired. Memory loss (as seen in Alzheimer's) is a subtype of dementia. Alzheimer's Disease represents the most common form of dementia in the adult population.

Memory - What is a memory? The ability to recall something. How are memories made? Well, we have a pretty good idea of the mechanism and brain regions involved. Where are memories stored? We know certain brain regions are important for making memories vs storing memories. Where is the memory of the lyrics to Taylor Swift's album stored? We could figure out the general area by hooking you up to a fancy machine, but here the pictures gets hairy. Suffice to say, memory formation/retrieval/consolidation/storage remain one of the key areas of research in neuroscience. What we do know is that Alzheimer's Disease involves impairment of memory processes.

Neurodegeneration - a process during which neurons progressively continue to die. Much like the progressive collapse of well-set dominoes, once this process starts, neurons continue to die over time, and there is very little (currently) we can do about it. What starts neurodegeneration in Alzheimer's Disease (Or, using our analogy, what pushes the very first domino?) ? We will visit this controversial question in future posts.

So, what is Alzheimer's Disease?

This disease, first characterized by Alois Alzheimer (hence the name) is a disorder in which neurons in key brain regions die. This results in the initial symptoms of memory loss and eventual death. Interestingly, patients of Alzheimer's Disease do not die of the disorder, per se, but it is usually the diseases associated with Alzheimer's (Pneumonia, for example) which is the direct cause of death. 

Alzheimer's Disease is an incredibly prevalent form of dementia in the elderly. And, as our sanitation, medication and standard-of-living continue to improve, the number of people suffering from it is only expected to increase. 

Please let me know if there are specific areas you would like for me to cover. You can reach out to me on twitter at @NipunChopra7.