In the previous post we discussed neuroception and the subconscious evaluation of threat by the sensory systems and the brain. Our ability to accurately appraise the environment — including sensory input, context, past history and future expectations, etc. — dictates the baseline or resting tone of the nervous system. As we age, these environmental influences on the system (and our cognitive appraisal of them) add up and shape how we perceive ourselves and the world around us. If stressors accumulate, both physical and psychological, and become more chronic without sufficient adaptation the resting tone of the nervous system is likely to increase.
Why does this matter? It matters for all the toned up, tweaked, anxious athletes/execs as well as the persistent pain and chronic fatigue people. So basically everyone. As resting system tone increases one becomes more rigid, disengaged, and invariant, with a limited ability to adapt and grow. Think of it as a spectrum between an open and flexible system vs a closed and rigid system (more on that in a minute). So how do we define resting tone and is it fixed?
The baseline tone of the nervous system is the starting point of the autonomic nervous system. It's the outlook or, maybe, the rhythmic midpoint. This tone determines how much tension we move with, how we interact with others, and our reactions/adaptability to stressors. Tone seems to be dictated by our perceptions of threat and the ability to cope with external demands. Too much threat and the reflexive, subcortical limbic system is lit up. Specifically, the amygdala gets sensory information from the autonomic nervous system and once sufficiently conditioned by prior experiences of threat or expectations (cognitive pre-experiences) the sympathetic nervous system is facilitated. The amygdala happens to connect directly to the hypothalamus-pituitary-adrenal axis (the birthplace of the stress response!) and in turn is highly sensitive to stress hormones creating a vicious cycle of increased neural tone. Repeat this sequence often enough and thru the wonders of neuroplasticity this tone becomes the resting state of the nervous system.
Obviously, the opposite is true as well in that those with a healthy, capable vagus nerve (remember it's cranial nerve X, the rest and digest one that decreases breathing rate and increases heart-rate variability) are able to engage with the environment in an open way that allows for flexibility and variance. There needs to be a healthy spectrum along which the person can function and meet all demands.
So the idea here is that there is a spectrum between an open, engaging baseline and a closed, disengaged baseline. On the open end, resting tone is low with a higher parasympathetic presence. On the closed end, sympathetic state dominates. Where we are on this spectrum is essentially a glimpse at the resting state of the nervous system.
A few key points:
This is what I see all too often: clients are chronically on the closed end of the spectrum, flooring it to a red light and losing the ability to oscillate across the spectrum. This limits the ability to engage in and improve with training. Those who are more open with higher parasympathetic tone at rest are better able to concentrate and use stress to their advantage when high performance and reactivity is needed.
So as coaches and physios we need to promote a sustainably low resting tone of the nervous system that is able to meet demands and respond to challenges in order to grow. How do we do this? Reduce threat and then work on these points I made in a prior post on high-tension movement strategies. More on this to come...
* I also highly recommend reading this amazing text by Robert Sapolsky, PhD as we'll continue to integrate much of his work going forward:
What determines if a client is going to do well with a particular training or treatment session? How about in a game or business meeting? Lots of ideas come to mind: strength and endurance, hydration, nutrition, mobility, preparation, etc. all of which are crucially important. However, there is something that occurs much sooner in the process that determines how well the above variables are expressed - neuroception.
Neuroception is the nervous system's evaluation of risk via sensory information from the environment as coined by Stephen Porges in his excellent text The Polyvagal Theory.
This neural evaluation of environmental risk occurs continuously on a subconscious level without cognitive involvement - primarily in the brain stem and limbic system while gauging the trustworthiness of people and their movements seems to occur in the temporal lobe (read Subliminal).
Depending on the level of threat perceived 3 things can happen:
1) one engages with the environment in a healthy, proactive, and curious way
2) one disengages via antisocial, aggressive behavior that is quite reflexive (basically like the people who go to Wal-mart late at nite) or;
3) freezing/immobilization occur from an inability to cope with severe stressors - think fainting.
Engagement (predominantly a parasympathetic function) occurs when the threat is minimal; the cortex actively inhibits the mobilization response. Two things occur when the perceived risk is minimal: 1) regulation of bodily state is maintained thru the myelinated vagus nerve and the stress response on visceral organs is muted. 2) social behaviors (especially thru the cranial nerves) are facilitated including vocal intonations, listening, facial expressions, and orientation of the head and neck*. The client can listen and engage in your coaching and the learning/treatment process because they are accessing higher brain states, specifically the prefrontal cortex.
On the flipside, disengagement (sympathetic fight or flight mode) occurs based on the perceived risk of the sensory inputs from the environment. In this situation, the cortex becomes inhibited and the brainstem/limbic system takes over. This explains why so many people under stress (including, but definitely not limited to, those in pain) are unable to stay connected - in relationships, in their performance, and definitely during a treatment or training session. Rather than living in their cortex, they are reflexively relying on lower brain regions and looking to literally get the hell outta there or completely shut down. It could be reasoned, then, that those who have a mismatch between perceived risk and actual risk - of a movement, the environment, sensory input - are unable to self-regulate. These are the people we struggle with clinically. The "difficult" client who can't perform the movements, forget what you showed them, and can never relax. This person likely has minimal HRV and is quite rigid neurologically.
Hierarchy of Needs
Maslow's Hierarchy of Needs is a great illustration of this point as everyone's goal should be the top of the pyramid: self-actualization. But in order to reach the top, we as humans have to be able to regulate our basic needs first. How can one be expected to experience benefits from a training program, perform well in a game, or even improve from physiotherapy if their brain is occupied by their physiologic and safety needs?
Neuroception is evolutionarily important in determining the safety of the environment for survival - without it our species would have stayed in the caves. However a mismatch in actual vs perceived threat alters the ability to maintain physiologic and behavioral homeostasis. And without the ability to regulate our basic needs, engagement with the environment thru sensorimotor processing is limited. This is why peripheral vision is decreased during stress (they literally have tunnel vision) and it's probably why movement suffers because if you can't perceive sensations accurately you don't make good motor plans.
We rightfully and nobly want people to achieve their full potential yet we as clinicians or coaches say/do the following and light up their brainstem (and inhibit the PFC) with threats like:
Without an appreciation for how each of these variables can be perceived as threatening to a specific individual, especially to those with neuroceptive errors such as those with chronic pain, anxiety, or depression, we are not helping them reach the output variables desired. Instead we are anchoring them to the bottom of the hierarchy and constantly forcing them to attend to basic needs. The human is an ecosystem and, thankfully, we effect all parts of it - so you better recognize!
The constant subconscious filtering of the environment can be optimized by nonthreatening stimuli** which are unique to each individual based on a number of factors and will elicit prosocial behaviors. Ultimately it is the connection - physical, emotional, social - that drives us up the hierarchy and allows for self-regulation and performance. The ability to establish a relationship and meet the client where they are in order to take them where they need to go is not only important on a behavioral level - it is crucial for the client's physiology. As Todd Stull, MD says, "regulators of physiology are embedded in relationships".
More on the relationship of neural tone and autonomics next time.
*I find it interesting that the inability to orient the head to perceive sensory information from the environment may set up a negative cascade of cervicomandibular rigidity causing further neuroception because if sensory input is narrow and not easily perceived, it likely is more frightening - like walking in a dark room.
**For more on how to improve nonverbal communication check out my guy Zac Cupples' excellent post.