Could the human brain be expanded?

This is a question that's often linked to science fiction. The idea that we humans only use ten percent of our brains is an urban myth. What this myth suggests is that we could eventually figure out a way to utilize the ninety percent that we're not using and become super intelligent. Much of this myth is attributed to the fact that some people, like Einstein, are geniuses and they use more of their brain's capacity than the normal population. This myth was revived in the recent movie 'Lucy' in which a drug gets into her blood and causes her to be able to tap her brain's unused capacity to have superhuman abilities.
The problem with this myth is that most of our brain is working at all times. The brain uses most of the oxygen and nutrients in our bodies. If we were only using ten percent this wouldn't be the case. The other thing to consider is that the brain is compartmentalized into regions that have specific functions. The only part that is responsible for higher thinking is the cerebral cortex. This myth has been propagated by science fiction stories about superheroes using their maximum brain capacity to do all sorts of super stuff.
So, could human brain capacity be expanded or enhanced in any way? The answer is maybe. The first method could happen with further human evolution in which the brain grows larger in size. This has a few drawbacks. First is the fact that the brain is heavy and a larger head would require us humans to have much stronger neck muscles. Then, there is the problem with oxygen and nutrient use. We humans would have to have a larger lung capacity and a higher metabolism to accommodate a larger brain.
The other method of increasing brain function has to do with the formation of synapses and the chemicals that act as neurotransmitters such as Dopamine, Epinephrine, Norepinephrine and Histamine. These are the chemicals that transmit electrochemical signals from a nerve axon to a nerve receptor dendrite, essentially across a synapse. In order to improve brain function, one would have to increase the number of synapses and improve the neurotransmitter process. Could a drug be created to do this? Some people believe that it has. Just listen to the ads that blast away on TV and in magazines. These ads tell you that their smart pill will increase your brain function or your money back. Not!
The cerebellum is the 'Little Brain that can' or so it seems. It lies near the base of the brain and it's only ten percent of the brain's size but has fifty percent of the neurons. Supposedly it has something to do with cognitive function and language. When it's damaged, it causes loss of motor control. The problem with enhancing this part of the brain is that no one knows how to influence it, which only emphasizes how much we don't know about the brain.
The real thinking part of the brain is the frontal lobe of the cerebral cortex. It's what makes us humans smart, or so we think--no pun intended. Again, no one knows how to make this part of the brain function better. Supposedly, brilliant geniuses like Einstein had more folds in his frontal lobe, but no one knows why this is. Does it mean that he had a higher brain capacity? Probably not. Supposedly, his brain was better connected between the hemispheres and he had a higher density of Glial cells, which support nutrition in the brain. Again, no one knows why this would be the case. One has to conclude that Einstein had a marvelous brain because of genetics. He was smarter than the average. How one could cause this to happen in a given person is unknown.
The way things are going one would be forced to conclude that human evolution is going in the wrong direction when it comes to brain capacity. We're not doing anything to exercise our brains. However, I believe that writing is one way to help our brains work better, especially as we age because writing takes thought. Thinking is one way to make your brain better. So keep writing.

Thanks for reading.