“Modern medicine has generally viewed the concept of ‘psychosomatic’ disease with suspicion. This view arose partly because no neural networks were known for the mind, conceptually associated with the cerebral cortex, to influence autonomic and endocrine systems that control internal organs.”
Psychosomatic illnesses are typically seen in pejorative terms — it's all in your head so it must not be real! Would a known biological mechanism lessen the stigma? For over 40 years, Dr. Peter Strick and his colleagues have conducted careful neuroanatomical tracing studies of motor and subcortical systems in the primate brain. A crucial piece of this puzzle requires detailed maps of the anatomical connections, both direct and indirect. How do the frontal lobes, which direct our thoughts, emotions, and movements, influence the function of peripheral organs?
In their new paper, Dum, Levinthal, and Strick (2019) revisited their 2016 work. The adrenal medulla (within the adrenal gland) secretes the stress hormones adrenaline and noradrenaline. To trace the terminal projections back to their origins in the spinal cord and up to the brain, the rabies virus was injected in the target tissue. The virus is taken up at the injection site and travels backward (in the retrograde direction) to identify neurons that connect to the adrenal medulla with one synapse: sympathetic preganglionic neurons in the spinal cord. Longer survival times allow the virus to cross second-, third-, and fourth-order synapses. The experiments revealed that cortical influences on the adrenal originate from networks involved in movement, cognition, and affect.
The mind–body problem: Circuits that link the cerebral cortex to the adrenal medullaBased on these anatomical results, the authors concluded with a series of speculative links to alternative medicine practices, including yoga and Pilates; smiling to make yourself feel better; and back massage for stress reduction.
“The largest influence originates from a motor network that includes all seven motor areas in the frontal lobe. ... The motor areas provide a link between body movement and the modulation of stress. The cognitive and affective networks are located in regions of cingulate cortex. They provide a link between how we think and feel and the function of the adrenal medulla.”
- Motor cortex provides major inputs to the adrenal medulla, especially from the trunk and axial representations of M1 (primary motor cortex) and PMd (dorsal premotor cortex).
“Because of this arrangement, we speculate that there is a link between the cortical control of 'core' muscles and the regulation of sympathetic output. This association could provide a neural explanation for the use of core exercises, such as yoga and Pilates, to ameliorate stress.”
- The orofacial representation of M1 provides a small focus of output to the adrenal medulla.
“This output may provide a link between the activation of facial muscles, as in a 'standard' or 'genuine' smile, and a reduction in the response to stress.”
- Another large motor output region is in postcentral cortex, corresponding to the sensory representation of the trunk and viscera in primary somatosensory cortex.
“This output may provide a neural substrate for the reduction of anxiety and stress that follows passive stimulation of back muscles during a massage.”I was a bit surprised to see these suggestions in a high-impact journal. Which leads us to the next topic.
Self-Care and Its Discontents
What can be bad about trying to reduce daily stress and improve your own health?
A recent paper by Jonathan Kaplan (Self-Care as Self-Blame Redux: Stress as Personal and Political)1 is critical of the way the self-care movement shifts the burden of alleviating stress-related maladies from society to the individual. Economic disadvantage is disproportionately associated with poor health outcomes, to state the obvious. Kaplan argues that focusing on individual self-care blames the victim for their response to a chronically stressful environment, rather than focusing on ways to effect structural changes to improve living conditions. In his efforts to highlight social inequities as a cause of stress-related illnesses, Kaplan goes too far (in my view) to discount all self-help practices that aim to preserve health.
It can be empowering for patients to be active participants in their health care, whether at the doctor's office, in the hospital, or at home. One great example is CREST.BD: A Collaborative Research and Knowledge Exchange Network at the University of British Columbia. They've established the Bipolar Wellness Centre (online resource to support evidence-based bipolar disorder self-management) and developed a Quality of Life Tool (free web-based tool to help people with bipolar disorder and healthcare providers use CREST.BD’s bipolar-specific quality of life scale).2
Then we have the wellness industry. Depending on what pop health source you read, there are 5, 45, 25, 12, 10, 10, 20 (etc.) essential self-care practices that you can incorporate into your daily routine (if you have the time and money). Wellness lifestyle insta-brands of the rich and famous hold up an impossible standard for upper-middle class white women [mostly]3 to attain. Perhaps our friendly neuroanatomists want to work on their core strength — they can follow @sianmarshallpilates for Pilates inspiration!
Back to Kaplan's point about blame...
It's easy to urge your followers to “stay happy!” and “move on!” if you have a net worth of $250 million, and if you don't have a psychiatric diagnosis. These 'Six Things' occupy a place in the pantheon of victim-blaming. People with mental illnesses are not effortlessly able to “stay happy!” or “move on!” or stop repetitive hand-washing (OCD) or avoid reckless spending (manic episode). And this is NOT their fault. And it doesn't make them mentally weak.
Most psychiatric disorders, in essence, involve thoughts, emotions, and/or behaviors that spin out of control. Here, I'm using control in a colloquial (but not absolute) sense, meaning: it's frequently difficult to stop a downward spiral once it gets started. Although overly simplistic...
- Major depression involves thoughts (ruminations) and feelings of worthlessness and utter bleakness that spin out of control.
- Generalized anxiety disorder involves thoughts (worry) about an imagined awful future that spin out of control.
- Panic disorder involves a thwarted escape or safety response to perceived danger that has spun out of control.
- Mania involves elevated mood and intense motivation for reward that spin out of control.
- Obsessive-compulsive disorder involves maladaptive repetitive behaviors (that spin out of control) meant to quell maladaptive worrisome thoughts that have spun out of control.
- Borderline personality disorder involves overly intense negative emotions that spin out of control and lead to self-destructive behaviors.
Computational Psychiatry
Or you can get mathematically fancy and formalize every single mental illness as a result of “faulty Bayesian priors”. Meaning, the brain's own “prediction machine” has incorporated inaccurate assumptions about the self or others or how the world works. A disordered Bayesian brain also ignores empirical evidence that contradicts these assumptions. The process of active inference — the brain's way of minimizing “surprise” when reconciling a top-down internal model and bottom-up external input — has gone awry (Prossner et al., 2018; Linson & Friston, 2019). Although a sense of agency (or control) is a critical part of the active inference framework, I don't think an impairment in active inference is a choice. Or that one has control over this impairment. In fact, there's a Bayesian formulation of behavioral control (or lack thereof) that considers depression in terms of pessimistic, overly generalized priors, i.e. the depressed person assumes a lack of control over their circumstances.
Learned Helplessness (Huys & Dayan, 2009).
Using this mathematical model, you can confound the “stay happy!” crowd when you use all 24 equations to explain the concept of learned helplessness and its relevance to human depression.
Maybe one day, Bayesians will have a stable of Instagram influencers. Get to work on your branding ideas!
Footnotes
1 Thanks to Neuroskeptic for tweeting about this paper, along with the quote that individuals may "end up being seen (and seeing themselves) as responsible for their own failures to adequately ameliorate the stresses that they suffer."
2 Full Disclosure: my late wife was a Peer Researcher with CREST.BD.
3 While searching for health and wellness Instagram influencers, I was pleasantly surprised to find @hellolaurenash (a Chicago-based blogger, editor, and yoga and meditation teacher who founded a holistic wellness platform for marginalized communities) and @mynameisjessamyn (a body-positive yoga expert who wants to change the largely white and thin face of yoga and make the practice more accessible to all). I know absolutely nothing about the prevalence of diversity among health and wellness Instagram influencers, just like I know absolutely nothing about Computational Psychiatry.
References
Dum RP, Levinthal DJ, Strick PL. (2016). Motor, cognitive, and affective areas of the cerebral cortex influence the adrenal medulla. Proceedings of the National Academy of Sciences 113(35): 9922-9927.
Dum RP, Levinthal DJ, Strick PL. (2019). The mind–body problem: Circuits that link the cerebral cortex to the adrenal medulla. Proceedings of the National Academy of Sciences 116(52): 26321-26328.
Friston K, Schwartenbeck P, FitzGerald T, Moutoussis M, Behrens T, Dolan RJ. (2013). The anatomy of choice: active inference and agency. Frontiers in Human Neuroscience 7:598.
Huys QJ, Dayan P. (2009). A Bayesian formulation of behavioral control. Cognition 113(3):314-328.
Kaplan J. (2019). Self-Care as Self-Blame Redux: Stress as Personal and Political. Kennedy Inst Ethics J. 29(2):97-123. PDF.
Linson A, Friston K. (2019). Reframing PTSD for computational psychiatry with the active inference framework. Cognitive Neuropsychiatry 24(5):347-368.
Prosser A, Friston KJ, Bakker N, Parr T. (2018). A Bayesian Account of Psychopathy: A Model of Lacks Remorse and Self-Aggrandizing. Computational Psychiatry 2:92-114.
Smash the wellness industry
... Wellness is a largely white, privileged enterprise catering to largely white, privileged, already thin and able-bodied women, promoting exercise only they have the time to do and Tuscan kale only they have the resources to buy.
Finally, wellness also contributes to the insulting cultural subtext that women cannot be trusted to make decisions when it comes to our own bodies, even when it comes to nourishing them. We must adhere to some sort of “program” or we will go off the rails.
The shortcut to money, health, relationships, success, or anything you want in your life is to BE and FEEL happy now!— The Secret (@thesecret) December 25, 2019
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