interesting article on day length, exercise, changes brain
 

http://www.economist.com/blogs/prosp...y-neuroscience

excerpts, great if your're a rat:

But doesn’t behaviour itself generate neurotransmitters like dopamine?

Yes. It is a closed loop system. The transmitters generate behaviour and the behaviour in turn shapes the brain and generates the transmitters. The brain changes itself through its own activity.

Doing crosswords isn’t good for your brain?

It is good for improving your crossword skills but does it lead on to other kinds of advanced cognitive function? No. There is no translation of the crossword skills to other skill categories. That shouldn’t discourage anyone, they are a lot of fun, but a vigorous hike will do more for your cognitive function.

What about playing an instrument? Don’t you have to use right and left brain for a stringed instrument?

Yes. That has clear cognitive functions that do crossover. Especially learning to play and read the music at the same time. But exercise is number one, diet number two and then social interaction. These are the important things for brain function.

What do you do to protect your brain?

I’m a rock climber and an ice climber. I go to the Sierra Nevada mountains, anywhere above 10,000 feet I’m a happy guy. At home I go to the gym.