John McManamy Health Guide
  • As you may recall from an earlier blog, we have two adorable cuddly young cats named Yogi and BooBoo.


    Not long ago, one of my housemates suggested I emerge from my room to check something out. It turns out that one of the little guys had brought in a tiny rattlesnake and deposited it by the door to my room. Following is a simplified account of what happened in my brain and the rest of me:


    … snake …


    That was basically all the information the cortical areas that govern my conscious thinking had processed. Further particulars would be too slow in coming. It was time to turn executive control over to my limbic system.

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    The limbic system is known as the lower or unconscious or mammalian brain. It doesn’t have time to ruminate over the fine points of any reptilian species my nature-loving cats happen to deposit by my door. It is built for quick action, based on whatever limited amounts of information it has available to it.


    An important region of the limbic system is the amygdala, which plays a critical role in fear and arousal. Think of the amygdala as a smoke detector. By now, my amygdala has the “… snake …” message from either my cortex or some subcortical area, but hasn’t quite figured out what to do with it. But a direct feed is coming in from the hippocampus, which looms large in memory. My hippocampus is telling my amygdala that the individual who writes blogs here at BipolarConnect equates even suspicious-looking shoelaces with the type of life form that emerged from John Hurt’s stomach in the movie “Alien.”




    My amygdala has sounded the alarm. Various neurons in the amygdala project into the nearby hypothalamus, which regulates virtually every gland in the body. Neurotransmitters from neuronal amygdala projections are now urgently signaling the neurons in the hypothalamus to do something.


    In response to the amygdala, the hypothalamus releases the hormone CRF into the short blood vessels connecting it to the pituitary gland at the base of the brain. My limbic system has basically turned over the mission to my sympathetic nervous system. The pituitary interprets the CRF as its cue to flood the hormone ACTH into my bloodstream, where it is dispatched to the adrenal glands, which sit on top of the kidneys. This hypothalamus-pituitary-adrenal connection is known as the HPA axis.


    Kurt Vonnegut picks up the action from here. In “Breakfast of Champions,” Vonnegut writes: "My adrenal gland added the glucocorticoids to my bloodstream. They went all over my body, changing glycogen into glucose. Glucose was a muscle food. It would help me fight like a wildcat or run like a deer."


    At about the same time, the adrenal glands, through instructions originating from the amygdala, are also pumping adrenaline into the bloodstream.


    By now, every part of me is primed for action. Since I don't need to be digesting food, my stomach and intestines aren’t doing much of that. All my available resources are being diverted into hyperactivity in my heart and lungs and sensory inputs, which in turn is readying me for the Second Coming of Michael Jordan.


    In short, in the space of a microsecond, “SNAKE!!!” translated into an amazing 60-inch vertical leap. If I had a basketball, I could have accomplished a slam-dunk with my toes. At the same time I emitted a high-pitched Alpine yodel clearly audible three time zones away. Coincidentally, that day in Minnesota, there were reports of moose in trees.


    As I descended to earth and assumed my patented Bruce Lee karate crouch, my frontal lobes were slowly starting to process visual and other information, such as:


    “Yes, that brightly-pigmented, braided-looking object on the floor truly is a snake and probably a rattler, at that, but it isn’t moving.” If the snake isn’t moving, it’s probably dead. On the other hand, can cats kill rattlesnakes?

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    “The snake isn’t coiled.” If the snake isn’t coiled, it’s probably not about to strike.


    A few more sensory and cognitive system checks, and the cortical regions of the brain were telling the amygdala to stop sending out the alarm. Soon, my breathing and heart were back down to normal, and I could start digesting food again.


    My reaction may have been a bit extreme. After all, it was only a rattlesnake outside my bedroom door. It wasn’t like it was Rosie O’Donnell turning up at my doorstep and telling me that she was lonely or anything.


    But basically, my fight or flight response checked out just fine: My limbic system raised the alarm based on the limited information available, then settled down (and the rest of me with it) once my frontal lobes had a chance to process more information and get the word back to the amygdala. Like any smoke detector, the amygdala is built to sound numerous false alarms. Better safe than sorry.


    The reason teens drive their parents nuts is because moms and dads are naively trying to reason with their kids’ limbic systems. The frontal cortex is not yet in full control. The circuits between the two brain regions and their intermediary regions don’t become fully operational until adulthood.


    But adults can have similar cases of faulty wiring. In some of us, the amygdala is hypersensitive. It may sound an alarm for no apparent reason. Or various feedback loops responsible for modulating the amygdala may not be doing their job. Or the rational part of the brain may have trouble talking sense to the lower parts of the brain.


    The results of all these dysfunctions can manifest in any number of ways, from panic attacks to PTSD to aggression to impulsive behavior to hysteria to depression to alcohol and substance use. In short, some brains are more reactive to the environment than others, which is why avoiding and managing stress is a paramount concern in living with a mood disorder.


    My fear of snakes will probably always remain with me, but only because I feel that working on this area of my life hardly justifies the investment in my time. But other parts of my life have been well worth the effort. I can now deliver a thirty-minute talk with no notes and without cowering behind a lectern, something I would have considered impossible less than a year ago.

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    Literally, through practice and determination regarding a specific activity, the thinking parts of my brain undid a lifetime of programming involving fear and memory and irrational thoughts and behaviors. This is why talking therapy and coping strategies and even belief in God work. What the current brain research is telling us is that even though there is a strong genetic and biological component to behavior, nothing is predetermined. We don’t have to be helpless bystanders.


    Back to my little feline furballs: Okay, now which one of you fellas brought in that snake?


    Meow-meow! Not me, daddy. Meow-meow! Not me, daddy


    Awww! You guys are too cute. Now go take your snake outside, but first give daddy a cuddle.


    Did you know that the limbic system is also involved in the warm fuzzies? But that is a whole other story …


Published On: May 27, 2007