Have you ever thought about how you think?

Think back to your first memory: do you remember it vividly or does it all seem a bit confusing? If you can recall details about the movie that you watched last night much more easily than your very first memory, most of us can relate.

By Hannah Wark

Photo: iStockphoto.com (SIphotography).

My first memory almost seems like a dream — I remember being in the backyard of the house where I grew up. For me, it’s much easier to recall what I did yesterday in much clearer detail than that long-ago memory.

Understanding what happens in your brain when you’re forming a new memory or learning a new task is part of my work as a graduate student at the University of Saskatchewan (USask). Learning and memory are important thought processes that control how you look at and change what’s happening around you.

Think of the memory part of the brain as a cluttered shelf that is filled with childhood toys, random facts and skills that you’ve picked up over your lifetime. While this shelf doesn’t really have any more room to add anything else, you can still rearrange the old things on the shelf to add something new.

This analogy is similar to what scientists think happens in the brain. Researchers who study the brain think of learning as the rewiring of the brain due to an experience, and memory occurs at these changed wires. This process of changing connections in the brain is called “synaptic plasticity.” Scientists think synaptic plasticity explains how all the cells in the brain can change to create new memories and learn new tasks. 

My research focuses on the connection between the increase in memory disorders and high sugar diets that doctors are seeing in recent years. I’m looking at lithium, a common drug used to treat mood disorders, and its effects on synaptic plasticity-related brain events in mice that have been eating a lot of sugar.

More specifically, I’m studying the long-term form of synaptic plasticity, which changes the state of the brain cells to either increase or decrease for more than 30 minutes. The increase in brain activity is called “long-term potentiation” while the decrease in brain activity is known as “long-term depression.”

In the lab, I can induce potentiation and depression in a mouse brain using tiny electrodes that stimulate and record the brain. This allows me to mimic what’s going on in the brain during synaptic plasticity, which allows me to perform experiments to further understand the cellular mechanism of learning and memory.

The brain will alternate between long term-potentiation and long-term depression to change and control how you interact with the world. In some cases, this controlled action between the increased and decreased states in the brain becomes unbalanced and can have a disruptive effect on learning and memory.

In previous studies, researchers have connected this unbalanced state of synaptic plasticity to mood and memory disorders. Scientists have found that the cells in the brain are changed similarly between these two diseases.

I’m observing the effects of lithium on synaptic plasticity because it changes memory and other cognitive abilities. My research may provide further evidence that lithium is a potential treatment for memory disease, such as Alzheimer’s disease, because of the effects it has on synaptic plasticity.

Synaptic plasticity is an important event in the brain that allows you to remember the movie you watched last night. It allows you to create new memories without forgetting the older memories by rearranging the connections in the brain via synaptic plasticity. Because human physicians have recently witnessed an alarming increase in memory-related conditions — such as Alzheimer’s disease — in their patients, the need to better understand the cellular mechanisms of learning and memory has become so much more important.

Hannah Wark of Regina, Sask., is a health science graduate student who is studying neurobiology at the University of Saskatchewan.