The brainstem “knows” what Paula’s normal breathing rate is. The brain “knows” that her breathing rate is too slow at 3 breaths per minute at rest when awake. The brain “knows” that it takes her a lot of effort to actively exhale all day long in order to have a normal tidal volume of . 5 litres. The brain ” knows” that she she exchanges only 1.5 litres of air per minute at rest when awake and well and smart.
And we can know as well, by measuring both her lung function and her respiratory rate. The respiratory rate will tell us about the skeletal respiratory muscle pump and the nerves in the periphery [neck and chest] and will describe a kind of phenotype that JS Haldane discovered in normal healthy adults and that E. Kraepelin discovered in people with longstanding but reversible attacks of insanity.
The brain stem also knows when for whatever reason her already borderline ventilation is threatened by an episode of respiratory infection and inflammation of the lungs.
We do not know. We take the motor and nervous function of the respiratory pump and the structures of the periphery for granted. Because we reserves are not aware of how we breathe. It is unconscious. It is involuntary. The brain stem and the body simply takes care of it. And it does so, even when there has been hidden damage. And we still feel normal, no matter how slow or fast our breathing rate at rest, as long as our lungs are fine.
Paula cannot raise her resting breathing rate during a viral illness affecting her physical health. The brain stem understands this. The brain organizes a strategy to keep her alive, even if it means sacrificing her brain function for a time. The brain stem does not care if Paula feels fear and confusion as a result and nearly looses her job because she suddenly has become temporarily and unconsciously incompetent.
The brain knows that the disturbance to her brain function involves hypercapnia and is therefore reversible. We of course, do not have a clue. We do not understand that the brain is trying to keep us alive through an episodic respiratory crisis. We do not understand that Paula cannot increase her breathing rate as would be expected. The brain, therefore must manipulate hormones and glands and tissues and blood and body temperature and thus behaviour accordingly.
The first strategy the brain uses is to reduce Paula’s motor activity and speech and cognition. This inactivity with the slow breathing cools down he body temperature. This is protective.
Or, maybe this is just the biological effect of increased hypercapnia. In any case, as long as the hypercapnia stays stable, although most likely too high, the cognitive effects will remit once the respiratory infection heals. This is indeed what happens to Paula, although it takes a long time and is unpleasant and confusing and disabling. And may cause her to loose her job, her friends and her dreams…..for a time…not knowing how long it will last….or what has happened…
Unfortunately, during this emergency, the brain cannot communicate this to her conscious mind so she will not be aware of what is happening. All she feels is FEAR. And although she can move, she doesn’t. In truth all she is doing is breathing in and out, with great [unseen] effort as if her life depends on it….because it does….but only the brain stem knows and understands this. The fear is probably from the surge of adrenaline [epinepherine] needed to power her respiratory muscles, slowly pushing only 1.5 litres of air despite increased unseen stiffness. She is not paralyzed but she is acutely aware of the stiffness in her upper torso and face. She is unaware that to others, her face appears mask like – stiff, and unsmiling. Do her eyes show the FEAR of mild [is it ever really mild] inner asphyxiation? I am not sure. When I saw her at work in this very state, I am sure I avoided her eyes, I was so spooked out be her sudden strange like zombyness-like being. I was scared of her.
The sympathetic activation will increase her epinephrine [adrenaline] and help her heart to increase its output and will increase blood flow to her respiratory muscles. This is key in her situation. Paula has no biological flexibility since she cannot increase her breathing rate easily. [and she does not know this.].
The cortisol will increase, lowering the inflammation in the lungs, allowing her to keep breathing. Unfortunately increased cortisol has the side effect of insanity so…..Paula will suffer from decreased mental function that she will not understand.
From the point of view of the brain, it is important to keep Paula alive until she survives, to wait it out, despite her quiet insanity.
to be continued…………