The brain’s neuroplasticity and the fact that you don’t use all of your brain, all of the time, means your brain has a backup, or a reserve. If something goes wrong in one part of the brain you might be able to use other parts to work around the problem. This backup is called neurological reserve and the more your brain has, the healthier it is. Reserve is made up of two parts: brain reserve and cognitive reserve, and both are important for your brain health.
You don’t have much control over how big your brain is, as its size is determined by your genetics.
Our brain very slowly starts to get smaller as we age. In other words, we all experience brain atrophy.1 But MS can also damage your brain; meaning brain atrophy may take place a little quicker, and if your brain decreases in size, so does your brain reserve.