 My name is Benita. I live in Acton, Massachusetts, and I'm in grade 5. My question today is, why don't we use all our brain cells? And what do we do with the brain cells that we are not using? Thank you. I'm Hannah Icarino, and I'm a researcher at the Pick Our Institute for Learning and Memory at MIT. I'm here today to answer a question. The question is, why don't we use all our brain cells? Well, guess what? We actually do. We just don't use them all at the same time. Now, there are three main reasons for that. The first being that there are two major types of brain cells. The first are neurons. These cells are the ones we traditionally think of as existing in the brain. They communicate with each other and help us perform all the tasks we normally perform during the day, like talking, learning, listening. Now, there's another type of cell in our brain that we don't think about as often. These cells are called glia. These glia are there to help the neurons do their daily tasks. So, when neurons are talking to each other and doing their normal activities to help us do our normal activities, they'll sometimes create waste, and glia will help clean up that waste. Another example of what glia do is that when the neurons are injured, say you bump your head and get a concussion, the glia will become activated and help fix the neurons so your brain can function properly again. We use all of our cells, but we don't use all of them at the same time. You wouldn't use those repair cells unless there was something to repair. The second example is that we need lots of different parts of our brain because we do lots of different things with our brain. To help us walk, we need our motor cortex, and it controls our feet and our legs, and it helps us walk in the proper pattern and control our muscles. To learn and form a memory, you need a totally different brain area called the hippocampus, and that brain area takes in outside information and packages it into a pretty little package so that we can remember that memory from now until forever. Now, of course, when we're walking, we're not going to want to use all our memory cells to control our legs, and so even though we'll use our memory cells and our motor cells, we'll use them at different times for different activities. The third thing is that the brain functions a lot like a computer. If we think about a computer having bytes where we're going to store memory, imagine if you used up all your bytes just by turning on your computer and saving one single file. That would be a very inefficient computer because you'd have to have a new computer for every document you produced. Now, think about your brain. If you used every cell for a single memory, you'd need a new brain for every memory, and that is just not possible. So, in response to your question, it's actually a rumor that we don't use all our brain cells. We use them all. We just don't use them all at the same time.