Summarize this article in one sentence.
Your brain is filled with literally billions of cells that contain a cell nucleus, axons, dendrites, and synapses.  One proven way to grow new neurons is to learn. The existing axons, dendrites, and synapses, need to be maintained so don’t get lazy. Continue to perform the things you already do, including sports, reading, puzzles, exercise, crafts, or music. The key to growing new neurons is to teach yourself something different, maybe even something that feels awkward at first. Neuroplasticity of the brain, or the ability to grow new brain cells, happens if you take charge and expose your brain to something different. Learn to juggle, dance, play a musical instrument, or anything that is new to you.  Even doing familiar things in a different way can help. For example, navigate your way through your home, safely, while walking backwards. Try anything you can think of that creates a challenge for your brain, but it must be something that requires you to think. Neurobics are exercises designed to stimulate new growth in the brain. The primary basis of neurobics involves using the senses to stimulate new brain pathways.Think of ways to challenge your brain by altering your sensory perceptions. Some basic examples follow:  Get dressed in the morning with your eyes shut or a blind-fold on.  Wear headphones that suppress sound while trying to verbally communicate with a friend. Include speaking and trying to understand what they are saying by mouth movements and hand gestures.  If you play the piano, try playing a simple and familiar piece with your eyes shut, or with two fingers taped together.  Try playing a simple piece using all fingers, but play the bass clef using your right hand and above middle C, and the treble clef with your left hand and below middle C.  Use your non-dominant hand for routine activities. Try brushing your teeth, combing your hair, and using a computer mouse using your non-dominant hand.  Write with your non-dominant hand.  Try writing several sentences from memory, perhaps the first verse of a familiar poem or song, making the letters upside down, as a mirror image, or from right to left on the page.  Try playing your favorite sport using your non-dominant hand.  Break your routines. Put your shoes on in the opposite order. Mow the yard in the opposite direction. Think of other frequent routines and alter their order.  Go for an early morning walk simply to identify smells around you.  Try to identify the ingredients in a meal just from taste and smell. A recent study used only strategy-based brain training, without introducing any elements of physical exercise, to improve blood flow in the brain. The results showed that whole brain blood flow was significantly increased by using only brain-training exercises   The point of the study was to increase whole brain blood flow using only mental exercises.  When blood flow to the brain slows down, atrophy of brain tissues results. Atrophy in the brain means that cells degenerate, important communicate pathways degrade, and the brain tissue and important structures shrink away.  The study enrolled people of all ages that had suffered a traumatic brain injury, with about 65% of the enrollees having suffered the brain injury at least 10 years prior.  Part of the group was exposed to strategy-based brain training, and the others were exposed to general teaching materials, for the same amount of time, about how the brain works.  The group that received the strategy-based training improved abstract thinking scores by more than 20%, memory function measures improved by 30%, and the whole brain blood flow showed a significant increase as compared to the control group.  Many of the group participants also suffered from symptoms of depression and post-traumatic stress disorder. Depressive symptoms were improved in the strategy-based training group by 60% and post-traumatic stress disorder symptoms improved by almost 40%.  Strategy-based brain training really works to increase whole brain blood flow and can help to prevent brain shrinkage. This form of brain training is common and can be found all around you, including in your daily newspaper.  Strategy brain games are any games that you have to think about to solve. Do a crossword puzzle, a word-scramble puzzle, complete a Sudoku puzzle, or put together an actual table-top puzzle. Puzzle games that are not left to chance, that require you to think about them to solve them, are considered strategy-based brain games.  Play with another person. Games like chess, Go, or even checkers, involve thinking about your moves, and anticipating the moves of the person you are playing against. Make a list of something you commonly do, like a grocery list or things to do that day, and memorize the list. A few hours after you have completed the list, or even the next day, try to remember everything on it. Start simple and systematically. As you get more comfortable with the easier problems, work your way into harder math. Make it even more interesting by taking a walk while you do the calculations in your head. Visualize a word, then create a way to challenge yourself using that word. One way is to think of other words that start and end with the same letters, or think of words that have more syllables than the first one but still rhyme. The musical experience is a valuable one. Do something musical that you are not accustomed to doing.  If you already play an instrument, learn to play a different one.  Join a singing group. Even if you cannot sing well, joining a choir or vocal group will significantly expand your brain function on several levels.  You will learn to understand organization of the music on the pages you will be singing, timing and rhythm, and organized singing. Plus, you will be exposed socially to a new group of people which provides a wonderful opportunity to expand your brain even further as you learn about music. Try a cooking class, auto mechanics, wood-working, sewing, or crafting.  Taking a class in something that you do not know how to do, but are interested in learning, helps to develop new pathways in your brain. This happens both by learning the new material and interacting with new people in a new environment. This is a very good way to improve cognitive function and thinking ability. New languages also help to expand your vocabulary which is associated with higher cognitive functioning. Plus, hearing and speaking a new language develops new pathways in your brain. Try a sport that is new to you, and consider one that involves at least one other player. Golf is a sport that you can basically play alone, but it is more challenging when you play with someone. This creates additional experiences for your brain to organize and react to, and therefore the growth of new brain cells and pathways result. The more conversations you have, the more your brain has to work in order to compensate and process the new information. If you have children, have conversations with them. The more conversations you have with your child, the smarter they will be. Having conversations on topics with people that have very different opinions challenges your brain, and your executive function abilities, to determine how you respond to the same topic but in different groups. The more diverse your friends are, the more your brain is challenged to become creative both in conversation and in participation of different types of social interactions.

Summary:
Grow new neurons. Try something new. Perform neurobic exercises. Improve whole brain blood flow. Try strategy-based brain training. Boost your brain by using mental exercises. Perform math calculations in your head. Create pictures of words in your head. Participate in making music. Take a class. Learn a new language. Learn a new sport. Talk to people. Develop friendships with a diverse group.