Celiac Disease and the Prediction Machine

I discovered that I was a celiac a few months ago and accordingly I am on a gluten free diet.  Compared to most conditions discovered in one’s late sixties, celiac disease seems almost inconsequential. However, it fits into the idea of prediction error minimization.  In effect, the environment has changed and I need  to change my predictions. Bread and beer are now bad. My automatic, intuitive prediction machine has not been getting it right. It is disorienting. I can no longer “See food, eat food.” I can change the environment at home, but in the wider world I need to be aware. My brain needs to dedicate perpetual, and at least for now, conscious effort to this cause. It is almost as if I became instantly even dumber.  It makes me more self absorbed in social settings that involve food. Not known for my social skills, I have been a good listener, but now not so much.  On my Dad’s 94th birthday, I ate a big piece of German chocolate cake, enjoyed it thoroughly, and then remembered that it was not allowed. In my particular case, I do not get sick or nauseated when I make such a mistake so my commitment is always under threat. This demands an even larger share of my brain to be compliant. My main incentive to comply is those photos of my scalloped small intestine. I note that I was diagnosed after years of trying to figure out my low ferritin levels. (It will be extremely disappointing if I find that my ferritin is still low.)

I should note that now is clearly the best time to be a celiac. Although eating at a restaurant is fraught with eating a giant dose of gluten, restaurants are making it easier and easier. With some restaurant research, you no longer have to tell your server that you are celiac and ask if  this item is made with wheat and inspect the kitchen, etc. Reading the menu often shows you gluten free items that are gluten free for everyone.

This is surprising considering the prevalence of the disease is no more than 1 per cent of the population. I am clearly benefiting from those people whom I considered border line crazy who for no acute reason want to be gluten free. Thank you Kim Kardashian. I wonder if there could be some phase change transition where in the long run, gluten is noted for its presence. On the menu, there will be a little picture of a wheat grain head next to the items that contain wheat. It makes me think of Gresham’s law where bad money pushes out good.  This seems more likely to me because I love to bake glutiny bread and have always considered it a kind of miracle.  So I can imagine bad bread pushing out good bread. There might be some push back on good bread only being made with wheat or good beer with barley. Yes, you can make some okay baked goods without wheat through borderline chemistry experiments, but it is not the same or close. In the first month of a gluten free diet, I made cookies and french bread that included xanthum gum. I overate them and in retrospect the recipes included far too much xanthum gum. I was in pain for a week. I could feel the location of my intestines.

Now let me try to move from my celiac disease to combine some ideas from minimizing prediction error and parallel constraint satisfaction theory. Diagnosing celiac disease is problematic. The list of potential symptoms are long and contradictory. One such symptom is anxiety. I am skeptical. I see it as more of a comorbidity. If you get ill when you eat, but you do not know what is causing your illness, you get anxious.  i can see how celiac disease can be anxiety inducing especially for people who have harsh symptoms. It forces one to listen to those interoceptive signals –probably too much— and this could  result in anxiety spirals. While you are listening for interoceptive signals, you are likely ignoring other signals. anxiety

In line with this, comedienne Aparna Nancherla, described anxiety as having a particularly edgy improv group in one’s head that needs just one word to spin countless scenarios that no one is comfortable with. And none of those thoughts has a future. As she said, “I am too aware of my body,” and that might translate into giving too much precision to interoceptive cues while ignoring other cues. Having experienced anxiety disorder, the spiraling of slightly crazy ideas just requires precision to be a little off for then the improv group goes to work and to make each scenario a little crazier than the one before.

Picard and Friston have postulated that a pathologic absence of precise prediction errors  (See post Predictive Processing  and Anxiety and other Maladies) may lead to feelings of trust, well-being, and inner peace, such as those encountered in some forms of epilepsy with “ecstatic” symptoms. This state could be understood as a disruption—by epileptic discharges in the insula —of the “comparator between predictions and real inputs” for multisensory integration and interoception. This could result in an “ultimate stable state” in which top-down signals would perfectly predict representations in lower cortical levels, which would be the state the brain is trying to achieve: a perfect prediction of the world, like the Oriental nirvana.

Dehaene and his colleagues (See post Dehaene: Consciousness and Decision Making)  have studied schizophrenics.  “Schizophrenics’ main problem seems to lie in the global integration of incoming information into a coherent whole.” Dehaene suggests that schizophrenics have a “global loss of top-down connectivity. Apparently in schizophrenics, the prediction machine is not making enough predictions. With reduced top down messages, sensory inputs are never explained and error messages remain triggering multiple explanations. Schizophrenics thus see the need for complicated explanations that can lead to the far fetched interpretations of their surroundings that may express themselves as bizarre hallucinations and delusions.

So we now have four examples. (1) In my version of celiac disease, no interoceptive information is transmitted to my consciousness or my analytic systems about my celiac disease. My prediction machine has decided to ignore my immune system. Maybe, those symptoms were so anxiety raising and yet relatively benign that survival was improved by just cutting the link. (2) Then we have the anxious, maybe me too. The anxious get those interoceptive signals and want to change their predictions like crazy. It keeps building until they do not trust any perceptions. (3) Then the certain epileptics  with ecstatic symptoms who think all their predictions are perfect. They do not need to change anything. (4) Finally, the schizophrenics who know something is wrong but get no reliable feedback, so have to devise complicated delusions to explain them.

So now I will try to look at this through the model of Parallel Constraint Satisfaction as devised by Andreas Glockner,  Tilmann Betsch, Marc Jekel, et. al. (See Post Parallel Constraint Satisfaction Theory) According to PCS individuals do not use qualitatively different heuristics as assumed by the adaptive toolbox approach, but differ in how sensitive they are to differences in cue validities. They merely capture individual differences in cue perception.  The model builds upon Brunswik’s lens model and experiments found that participants were insufficiently sensitive to differences in cue validities to approximate the naive Bayes solution. The model creates a parameter (Parameter P) that incorporates that sensitivity to cue validities.

Prediction error minimization proposes that the brain tries to slow down the onslaught of sensory information so that it can understand the causes of sensory input. Parameter P might capture some individual differences in this.  People with a lower Parameter P might be “slower” to respond to new information from the environment or maybe to trust information from the environment less.  In other words, our brains as Bayesian machines update beliefs or expectations based on exteroception, proprioception, and interoception (See post Neuromodulation). Parameter P might represent our individual differences in deciding what is valid and then responding. This might include two components, one for recognizing the validity and another for responding. The idea that a significant amount of our personality or cognitive style or perceived intelligence might be based on our differences in a single parameter may seem crazy, but  modeling  like Conway’s Game of Life shows us the complexity that can be generated by a simple rule.  Kahan’s scientific curiosity might make up part of Parameter P. Those high in science curiosity might be more sensitive to changes in cue validity because they want to experience the pleasure of contemplating surprising insights into how the world works.

So maybe a test could be devised to determine our individual sensitivity to changes in cue validity. Then maybe we could adjust our individual behavior closer to Bayesian. Unfortunately both Prediction Error minimization and Parallel Constraint Satisfaction describe, but they do not get to the specifics such as how schizophrenics can start making more predictions.