This great graphic is really an MRI of the brain. It was posted by Maria Popova on her always stimulating blog, Explore. The MRI was provided by Dr. Chuck Hillman from the University of Illinois...
...It shows that after a 20-minute walk there is increased brain activity and the particular type of activity is generally associated with happiness.
It is a useful reminder of the interconnectedness of the mind and body (with apologies to the usual dualism presented). It is also a good reminder that by exercising our bodies, we also reinvigorate of brains.
Interestingly, Biff Spackle was able to secure an MRI scan of a typical progressive's brain.
Hat tip: BadBlue Money.