How brain smart are you? The human brain holds many mysteries. Take this quiz to find out how much you know about this complex organ. Brain_Injury_Society_Toronto published on June 02, 2014104 responses 2 Questions in vertical order At what age does the human brain reach full maturity? 18 years 13 years 25 years Choose the correct answer: Your brain is made up of 100 billion neurons. If neurons die as a result of an injury, they are able to regenerate. Yes, neurons can regenerate. No, neurons can not regenerate, and there is no treatment available to help bring them back. No, neurons can not regenerate on their own but a stem cell transplant allows new neurons to grow. Your brain is a soft, jelly-like organ. The skull is its only protection.How thick is the human skull? 1/2 an inch thick 1 inch thick 1/4 of an inch thick Choose the correct answer: a brain injury can result in a personality change. Yes, your personality 'sits' in the frontal lobe of your brain, and an injury to it can completely change who you are as a person. No, even with a brain injury, a person's personality can not be altered. Yes, but only if a person is in a coma for a long period of time. Choose the correct answer: a brain injury can only occur if a person loses consciousness. Yes, if a person has not lost consciousness they are not at risk of a brain injury. No, a person can suffer a severe brain injury even if they never lose consciousness. No, a person may have a brain injury even if they never lose consciousness, but it wouldn't be a severe one and they would likely make a complete recovery.