FYI, that "seeing stars" phenomenon comes from a whack to the occipital lobe at the back of the brain, the part that collects visual info from the eyes and interprets it into actual sight for us.
I'm seeing a huge increase in middle-aged casual riders in our area - ma & pa taking in a mile or two on their old bikes - FANTASTIC! - but almost no one wears a helmet. MADDENING!
I was at a brain injury conference where a police officer got at award. He designed a program - gift certificates from stores, presented to kids found cycling & wearing helmets. He's working to make it a national program. Carrots work better than sticks!