The Science Behind Procrastination

To further illustrate prefrontal cortex vs the limbic system, here's an example of how it works with procrastination
http://www.realsimple.com/work-life/life-strategies/time-management/procrastination

Science explains Charlie Brown’s seesaw sensibility as a fight that is sparked between two parts of the mind when it’s faced with a distasteful activity: a battle of the limbic system (the unconscious zone that includes the pleasure center) and the prefrontal cortex (the internal “planner”). When the limbic system wins, and that’s pretty often, the result is putting off for tomorrow what could (and should) be done today.

Here’s a bit more scientific backup, so you can stop blaming yourself (or your parents, your birth sign, the weather) and start chalking up procrastination to biology. The limbic system, one of the oldest and most dominant portions of the brain, is on automatic. It tells you to, say, pull your hand away from a flame—and also to flee from unpleasant tasks. In other words, it directs you to opt for “immediate mood repair,” explains Timothy A. Pychyl, Ph.D., a psychology professor at Carleton University, in Ottawa, and the author of The Procrastinator’s Digest: A Concise Guide to Solving the Procrastination Puzzle ($16, amazon.com).

The prefrontal cortex is a newer and weaker portion of the brain. It’s what allows you to integrate information and make decisions. “This is the part of the brain that really separates humans from animals, who are just controlled by stimulus,” says Pychyl. The prefrontal cortex, located immediately behind the forehead (where we tap when we’re trying to think, dammit, think), gets the job done. But there’s nothing automatic about its function. You must kick it into gear (“I have to sit down and write this book report!”). And the moment you’re not consciously engaged in a task, your limbic system takes over. You give in to what feels good—you procrastinate.