Your brain is an incredible organ, with around 100 billion nerve cells working together to keep you sharp and quick in your thinking. However, just like the rest of your body, your brain may not stay as vigorous as you age. You might find yourself writing things down more often, forgetting appointments, or struggling to follow a conversation or TV show without straining. Fortunately, just as you can exercise your body to keep it in shape, you can also exercise your brain. According to Hermundur Sigmundsson, a professor at the Norwegian University of Science and Technology’s (NTNU) Department o…