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4/30/13

She Has No Fear, Which Is Dangerous

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Near the opening of David Lean's epic movie, Lawrence of Arabia, we view Lawrence with non-coms in the mapping room of British HQ, Cairo, during WWI. As if damning the British class-system, Lieutenant Lawrence (Peter O'Toole) strikes a match to light a corporal's cigarette, then very slowly closes his finger and thumb upon the flame. His face is very attentive while the sergeant and corporal watch, fascinated, as Lawrence extinguishes the flame. The corporal then tries the trick with a burning match but drops it in pain. He complains that it hurts, to which Lawrence answers, "Certainly it hurts."

"Well what’s the trick then?" asks the corporal.

"The trick," says Lawrence, "is not minding if it hurts."

The scene serves as a metaphor of what neuroscience has learned about pain.
It follows a path under two-way control--brain to finger and not just finger to brain. As Lawrence says, "The trick is not minding if it hurts." As an heir to the Victorian age, Lawrence means will power conquers--that conscious will can be invoked to suppress pain. The brain has some say in the matter. Modern neuroscience reveals that it also has its say at an unconscious level.

We have an image of our bodies, not surprisingly called body image. On the one hand, it is no stretch for us to think that an image of the body is projected onto it by the brain, the seat of thoughts and imagination.

Pain image. On the other hand, it is a stretch for us to think that pain is like body image. That is, pain is projected onto the body by the brain. This just doesn't fit common sense. Indeed, traditional neurology held that pain receptors from, say, the foot send a one-way signal to the brain, and we say "ouch," or worse.

A new view has it that instead the brain and the body work a two-way street and when sensing something wrong in the foot the brain projects pain onto it. V.S. Ramachandran is among those who think about pain this way. It seems that there is a "gate" in the brain that controls the flow of pain. Men in combat may be wounded as grenades are tossed and mortar rounds explode around them, but they keep fighting, unaware of pain. Only after a helicopter carries them off to a field hospital do they begin to feel the wretched state of their body.

Soldiers in battle exemplify the view that pain is not merely a reflexive response to injury but is instead an opinion maintained by the brain which, if given time to attend to the pain, comes to notice it.

Ramachandran examined the phenomenon called "learned pain," wherein he believes chronic pain rewires the brain. Chronic pain lasts long after the original injury and causes agonizing discomfort. The wound has healed but the pain remains. His theory is that the brain rewires itself to "guard" against pain. At the time of the wound, the brain caused pain to insure the victim would not move the injured limb, thus allowing it to heal. After healing, the brain does not re-wire itself, but instead retains the pain-sensitive neurons although the member is no longer injured.

This is similar to phantom limb syndrome, in which after an arm or leg has been amputated the amputee still senses the presence of a ghost limb, often with pain in it. He looks where the pain is coming from and sees nothing but empty air. Clearly neurons in part of the brain are working overtime but get no feedback that they are sparking for nothing. (Click on "The Man Who Mistook His Foot For A Penis" in the sidebar. Also see A Phantom Arm and A Bizarre Experience.)

I see this as another example of the brain's remarkable plasticity. You can throw out the notion that you are hard-wired from birth, that you are biologically determined by your neurons. (My neurons made me do it.) That was called the bottom-up approach. It held that we are constructed out of parts and can never be more than they are. Neuroplasticity holds that top-down is also a form of control. For patients with obsessive-compulsive disorder (OCD), and with his use of the 4 "R's", Jeffrey Schwartz trains them that top-down works when they learn to Relabel their thoughts; Reattribute them ("It's not me; it's my OCD"); Refocus attention to desired new behavior; and, Revalue the OCD impulses as merely meaningless signals. But I digress, so on to my next topic.

Pain is one thing, fear another. Fear arises deeper in the brain, in a more primitive circuit than pain. With cortex removed, animals no longer suffer pain but can still be conditioned to a fear response. While pain is associated with a proximate physical cause, fear produces stress and as anxiety is more free-floating.

At the bottom of the Great Depression, Franklin Delano Roosevelt said we have nothing to fear except fear itself.  He wanted citizens to screw their courage to the sticking place in order to survive terrible times. This was a fine and memorable inaugural speech but from a neuroscientific vantage it suggests that fear is a bad thing.  It is not. Fear is important for our survival as individuals and as a species.

On each side and deep in the brain, two objects the size of large nuts help form the seat of all fears--the amygdalae, or amygdala. They are implicated in fear and anxiety. The amygdala sorts information entering the brain, detecting anything that threatens survival. The red alert goes up for any danger, and quickly triggers a fight-or-flight body response. Among the oldest parts of the primate brain, the amygdala receives input from the sensory world constantly, but "sleeps" through the world until danger is sensed. When the sound of a rattlesnake is heard, the amygdala instantly becomes your friend.

I like having it as a friend, but wonder what life would be like without it. I don't have to look far for an example.

Can neuroplasticity help her?

Consider the case of SM, as she is called.  She has no fear and she needs it. Could neuroplasticity exercises help her as they have helped Jeffrey Schwartz's OCD patients?

SM has no fear of snakes. She has trouble recognizing fear in facial expressions. Once a man jumped up from a park bench, pressed a knife to her throat and hissed, "I'm going to cut you." SM heard a church choir practicing in the distance. She looked calmly at him, and said, "If you're going to kill me, you're going to have to go through my God's angels first."

The man suddenly let her go and ran away. She didn't run home. She walked. But she caused the problem when the man beckoned her and she fearlessly went over to him.

I ask if neuroplasticity exercises could help her because--although normal in other respects--she has a damaged amygdala, the result of a very rare genetic disease. As I understand, she has none--or almost none--left.  She is able to feel other emotions such as happiness and sadness. This suggests that the human amygdala is pivotal for triggering fear.

Before her disease she knew fear, but today does not. She is a danger to herself, having had numerous encounters with events that should have left her shaking. Some day she may get herself killed or raped or otherwise harmed. Or, her fearlessness may bring harm to others.

Justin Feinstein, University of Iowa, has studied her with his colleagues, and has done so for 20 years. She has proved an interesting  case, and studying her has helped him understand how the brain processes fear. Indeed, he has used his knowledge to help returning veterans with post-traumatic stress disorder (PTSD).

Can nothing be done to help her, however? I would like Feinstein to say more about that. She has become something of a minor celebrity in academic circles.  Does her case reveal that without amygdala,nothing can be done to restore fear? 

I don't know. I ask myself, Has Feinstein expanded research into neuroplasticity and the amygdala for her as Schwartz has done with neuroplasticity of the cortex, basal ganglia, and thalamus for OCD patients?

Here is another question. Through neuroplasticity, can other parts of the brain be rewired to take over what SM's damaged amygdala areas once accomplished?

In short, is this where neuroplasticity reaches its limit?

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