"A pair of thumb-sized structures deep in the center of the human brain are critical for our ability to learn and remember. Thanks to their shape, each of them is called hippocampus — which means seahorse in Greek. These brain areas have the unique capacity to generate new neurons every day. In fact, recent human studies have shown that there are 700 new brain cells in the hippocampus every day. Most of these neurons, however, do not survive. In their new-born (pre-mature) phase, they need a great deal of support to survive, grow, and become an active member of the hippocampal community of neurons.
Research shows that we have the capacity to grow new neurons above
and beyond what is generally produced in our hippocampus and to
make them become mature and strong within weeks and months. The best way to generate new hippocampal neurons is to exercise. . . "
Rest of article here.
But it can also shrink . . . so look out.