How many connections can one neuron have?

After birth, our rate of brain neuron creation slows down while the rate of connections skyrockets. It's normal for each neuron to have 1,000 connections. Over time, neuron creation stops altogether, then actually goes into reverse as nerve cells gradually die. The brain can still be fine-tuning its internal network well into our twilight years.

On average, only 10 percent of the messages to a neuron come from the rest of the body or from lower parts of the brain's hierarchy of operations (the "unconscious" part of our brain, which controls things like breathing and heartbeat). The rest is taken up by an enormous network of relationships with fellow neurons in the "conscious" part of our brain, all constantly providing feedback to each other—the brain's almost round-the-clock conversation with itself.