Autopilot by Andrew Smart Read Free Book Online Page A

language, or to radically change your life: your brain will change, too.
    As an adult, these changes may be more stressful, but they are often good for your brain’s long-term health. What’s also unknown is whether or not lazy people have larger or more active default mode networks. Would this be a cause or a result of being idle? If ten thousand hours of practice are needed to become an expert violinist, how many hours of being idle are required to become a master idler?
    The measure of how well the nodes in your default mode network are communicating is called “functional connectivity.” Functional connectivity is used to indicate how well your default mode network is working, and can provide information about your brain health in general, like the measure of how fast and safely air traffic travels between airports.
    When you are at rest, fMRI data can be used to see whether the nodes in your default mode network are active together. It is possible to see if oxygen in the blood at these regions increases or decreases at the same time. If you have a healthy brain and you are at rest, you will have high functional connectivity in your default mode network. As you age, if you don’t get enough sleep, if you have Alzheimer’s disease, or if you’ve had a stroke, the functional connectivity in your brain decreases, perhaps because of damage to nodes in the network.
    It follows that a lifetime of being super-productive and pointlessly-busy might also decrease the functional connectivity in your default mode network. Until Marcus Raichle discovered the default mode network, the only functional or structural networks neuroscientists thought were important were the ones they studied, which became active during tightly controlled experiments. This is because most brain scientists and psychologists assume that the brain’s primary purpose is to process external information.
    Until very recently, it has only been possible to study how humans respond to external stimulation. It wasn’t until we developed the technology to see inside the living brain and study its activity during idleness that we discovered that most of the brain’s activity is dedicated to internal operations.
    This does not in any way reduce the importance of what we’ve learned about how different systems in the brain respond to the environment. The motor system, for example, forms and executes commands to your nerves and muscles in your limbs to carry out actions, or to react to events in the world, such as an incoming tennis serve. This system has been studied for decades. But it turns out that when the motor system engages and tells your arm to swing a tennis racket after (or actually before ) your visual system has reported an incoming serve, it might be only using a very tiny fraction of your brain’s total energy.
    While it is vitally important that neuroscience discovers what it can about the motor system, it may only be scratching the surface to study discrete areas of the brain while ignoring the “noise” of the resting brain. Noise, technically speaking, is some unwanted signal that usually interferes randomly with whatever signal we are studying. But the network that Raichle observed seemed to “deactivate” during active concentration on a stimulus and did not behave randomly. Nor did it interfere with signals of interest. It behaved perfectly regularly: when a subject begins actively thinking about something, this network deactivates.
    Why would a network in the brain decrease its activity during targeted mental tasks like remembering a list of words? Even more mysterious is the fact that the network decreases its activity regardless of the mental task in question. Looking at many different experimental conditions, the same thing happened: this network deactivated as soon as the subject began to perform an experimental task. Naturally, he wondered what happened to this network when people