Dementia: The Brain

In my last post I talked about the difficulties in diagnosing dementia. One thing that adds a significant challenge is how difficult it is to really be able to see and test what is happening in the brain – it’s not safe to be poking, prodding, or cutting into that thing!

So what’s happening in a brain with dementia? There is a lot we know, but still a ton we don’t yet know about dementia.

Here’s what we know:

  • Pathology (physical signs) of dementia can start in the brain as far as 20 years prior to symptoms of dementia like significant memory loss (Specifically with Alzheimer’s disease).
  • The brain starts to lose the flow of information through key parts of the brain called neurons and synapses because neurons die and/or synapses are destroyed. This means that a path of information that may have helped us remember or make sense of something is no longer there.

So what’s in a brain? Well we have a large sheet of tissue that is crumpled up inside our skulls, and this is called the cerebral cortex. The cerebral cortex understands what is happening in the rest of the nervous system and it is divided in 4 lobes: frontal, temporal, occipital, and parietal. The most human part about us is our ability to understand a situation, its nuances, and know how to behave, and this happens in our frontal and temporal lobes.

We also have a wishbone-shaped section of the brain called the hippocampus. The hippocampus is where we store our short-term memory in a given day. When you meet someone new named Jennifer at a breakfast meeting, her name is stored here so that when you see her later that day at the final presentation, you can say “Hi Jennifer.”

At night, when we sleep, our cerebral cortex turns off and rests and the hippocampus transfers all of the events from that day into the cerebral cortex to be stored as memories. This is when short-term memory becomes long-term memory (and why sleep is so freakin’ important).

When our loved ones have dementia, the cerebral cortex and hippocampus are severely affected – starting with the hippocampus in the early stages (and even before we really see symptoms). As you can imagine, when the hippocampus doesn’t work, the “thread of the day” as the University of Tasmania faculty put it, doesn’t exist. This is why our loved ones get confused with daily activities and new things.

What is actually happening to these parts of the brain?

The brain cells are dying; and when a brain cell dies, its connections to other brain cells no longer function either. You’ll hear references to “synapses,” the connections between one cell and another that help the brain transfer information. We need these! Without them, we lose the ability to observe, understand, and act normally in our environments, as well as a host of other things we see as symptoms of dementia.

This is one very elementary reason why curing dementia is such a challenge – dead brain cells cannot (currently) be brought back to life. Once they’re gone, they’re gone.

You will also hear reference to the existence of proteins and tangles in the brain that cause these dead cells. This gets complicated fast, so we will leave that for a future post!

Go get some sleep!

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