Thinking With Your Body

Watch the TEDTalk that inspired this post.

I'd like you to imagine a specific incident in your past. Imagine the last time you were afraid. I mean really afraid -- terrified. It might have been a close encounter with a robber on a dark street, or quaking just before speaking in front of a crowd, or a personal phobia, such as fear of heights or flying. Recall the sensations of that fear -- the racing heart about to burst, panting, intestines twisted into knots, knees shaking and hands trembling, cold sweat oozing out of your palms and beading up on your forehead.

Now imagine exactly the same scene, but without any of the bodily sensations that fear brings. No sweaty palms, heart rate and breathing calm, your muscles relaxed and your stomach content. Are you still afraid? What would fear be without the body? Can fear exist only in the mind?

Much of what our nervous system does originates outside the brain. The practice of tai-chi and yoga are based on the body controlling the brain rather than the conceited presumption of our conscious mind that it must always be the other way around - Dr. Douglas Fields

If the bodily sensations produced by fear are instead evoked artificially by direct stimulation of nerves in the body to set the heart racing, for example, you will feel afraid. You would experience something of a panic attack initiated by the body rather than unleashed by the brain.

The wonderful TEDTalk by Amy Cuddy highlights that our body can affect our brain and influence our mental state, our hormone levels, and our behavior. This is especially so for body language. Of course this is true and it should not come as a surprise. It is only the cerebral chauvinism of our conscious brain that makes this seem so surprising; but in fact, much of what goes on inside our head is unconscious; much communication among people (and all communication among animals) is non-verbal; and much of what our nervous system does, originates outside the brain. The practice of tai-chi and yoga are based on the body controlling the brain rather than the conceited presumption of our conscious mind that it must always be the other way around. Manipulating the body is how our mind is relaxed and soothing hormones are released by massage. It is how art and music, taste, touch, sights, and smells move our mind and behavior. We close our eyes or cover our ears to quell fear. It helps, at least at the movies. Sexual arousal usually originates by manipulating the body and this does have rather profound effects on the brain, hormones, and behavior. (Enough said on that subject -- let's move on.)

The fact is that most animals get by just fine with no brain at all. Their "brain" is their body. Creatures like worms, insects, and snails, all eat, reproduce, sense the environment and defend themselves without any difficulty in the absence of a brain. Some, like ants and honey bees, have complex social structures and sophisticated means of communication and they can even learn, all without having a brain or even a spinal cord. The nervous system of animals without brains is a knotted network of neurons connected together and cast throughout their body. Often neurons are wadded together and stashed next to the body structures they operate, such as the bunches of neurons clustered like grapes next to each segment of a lobster's articulated tail A similar neuroanatomy is true of people, but human beings with their emphasis on conscious intellectual functions easily overlook this and assume that the brain does it all.

Many neurons in people, in fact most of the neurons associated with producing the sensations of fear, are not located in your brain at all, or in your spinal cord for that matter. They are stashed in clusters throughout the body close to where they are needed. All of the sensations of touch and pain, for example, come from neurons tucked next to each vertebra in our backbone. The neurons setting our heart racing, our skin to sweating, and our stomach churning, are draped in a network throughout the body cavity next to the organs they control, completely outside the brain and spinal cord. So it should not be surprising that the body itself in stimulating these neurons would affect the brain and the conscious and unconscious mind, which would in turn affect hormones, mood, mental function, and behavior. When we manipulate our body, be it dance, a smile, or posture, we also manipulate our brain. This basic neuroanatomy lesson may hit some like a blow to the Solar plexus, that knot of neurons in the belly that controls breathing and other organ functions.

Pity those frugal folks who took the economical approach to achieving immortality by freezing only their head after they died so that they could be revived in the future rather than suffer the expense of freezing their entire body. They will be in for a rude awakening. If medical technology ever makes that awakening possible they will learn the difference between the brain and the nervous system. They will find that the latter resides throughout the body and that it informs and regulates the brain and infiltrates our mind.

As far as non-verbal communication is concerned, the evidence goes well beyond everyday experience and insightful psychological studies. Cognitive neuroscientists can see regions of the brain become activated subliminally in response to body language in numerous studies of people in brain scanners (functional MRI machines). Seeing fear on the face of another person trips fear circuits inside the brain of the observer. The rhythm of speech, music, and even eye blinks, regulates brain waves and couples brain wave activity between people unconsciously and without language. (Although language will do that too. Who did not feel emotion when seeing and hearing Amy share her story of personal triumph? As you did, the waves of neural activity sweeping through her brain were matched precisely in your own brain.) With these new brain imaging machines, the conscious brain is beginning to see how much is going on in the nervous system outside of its domain.

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