Interpretation & Actual Result of "10% of your brain" Myth It is well known that the common myth that an individual  only ever uses 10% of their brain is.. well, a myth. I had a question about a possible interpretation of this idea, and a follow-up question about the result of that interpretation. 

After spending a small amount of time with computational neural networks, it seems that at any given time, a small percentage of neurons are actually firing. All neurons have the potential to be firing, and at some point in execution likely will fire, but due to efficiency, only very few are needed for a particular function. This is my interpretation of what I have seen so far.. is this interpretation valid for the activity of neurons in the brain?

If this is valid, what would happen if 90-100% of neurons were firing at all times? I'm assuming this would be a huge disadvantage to whoever this happened to. Epilepsy? Overheating? Would the body be overworked and go into shock?
It is correct that only a small percentage of neurons increase their activities  relative to their baseline level in response to   new stimuli or to more abstract thoughts. There are many computational advantages to this. For instance, in deep learning, sparse coding is a class of unsupervised methods for learning sets of over-complete bases to represent data efficiently. Basically you have more combinations to store patterns if you activate a few cells than if you either activate too few or too many.