Painted using a continuous line to show an expression of continuous thoughts going on and on, over and over in the mind. One tries to shut the chatter off, but there it is, forever present. Even whilst asleep, the chatter carries on and even speeds up a gear.
It's the reason why some people must have background noise on all of the time, because it's better than their own thoughts racing through their minds. Do animals have this problem also? We know that they dream and have rapid eye movement whilst asleep.
This is painted on wood panel, and you can see the grainy texture through the paint drips.