Lisa Feldman Barrett, a well-respected neuroscientist, psychologist and known for her groundbreaking research on emotion, the brain, and the mind, shares some sublime insights in her book “How Emotions are Made. The Secret Life of the Brain”, that will blow your mind. In this blogpost I would like to highlight some key points from her book that may be very relevant to physiotherapists.
Lisa Feldman Barrett explains that our brain is not just for thinking. Our brain’s most important job is not rationality, not emotion, not imagination or creativity or empathy, she says. Our brain’s most important job is to control our body, to manage allostasis by predicting energy needs before they arise so we can efficiently make worthwhile movements and survive and perform nature’s most vital task: passing our genes on to the next generation.
Of course, our brain does think, feel and imagine. But all of these mental capacities are consequences of a central mission to keep us alive and well, managing our body budget, to stay healthy and live a longer and more meaningful life.
Our brain predicts almost everything we do.
Like those ancient, mummified Egyptian pharaohs, the brain spends eternity in a dark silent box. It learns what is going on in the world only indirectly via scraps of information from the light, vibrations and chemicals that become sights, sounds, smells and so on. Our brain must figure out the meaning of those flashes and vibrations and its main clues are our past experiences. So, trapped within the skull with only past experiences as a guide, our brain makes predictions. Through prediction, our brain constructs the world we experience.Predictions are simulations of sensations and movement. These sensations are compared to actual sensory information input from the world. If they match, the predictions are correct and the simulation becomes our experience. If they don’t match, our brain must resolve the errors and make adjustments (see image for Barrett’s model of a prediction loop).
If there is some prediction error, our brain has three options. First, it can change its predictions to respond to the data. Secondly, it can selectively choose data that fits the hypotheses or thirdly, it can ignore the data altogether maintaining that its predictions are reality.
Our brain not only predicts the sights, smells, sounds, touches and tastes from the outside world (exteroception), but also predicts movements and sensations from our inside body world, known as interoception.
The brain’s “interoceptive network” has two distinct parts.
One part, the body-budgeting regions, more commonly called visceromotor limbic circuitry, are the most powerful predictors of the brain and send predictions to the body to control its internal environment, like speeding up your heart beat.
The second part, the primary sensory regions, predicts the sensory consequences of that prediction. Like the pounding feeling in our chest after speeding up our heart beat.
The body budgeting regions play a vital role in keeping us alive. Each time our brain moves any part of your body, inside or outside, it spends some of its energy resources. We replenish our body’s resources by eating, drinking, and sleeping or by relaxing. To manage all this spending and replenishing, our brain must constantly predict our body’s energy needs like a budget, just as a company has a finance department.
Normally, our body budget fluctuates throughout the day.
But when our brain estimates badly, our body budget tilts out of balance. Short time imbalances are nothing to worry about. But when the budget imbalance becomes prolonged or chronic, our internal dynamics change for the worse. The effect of chronic misbudgeting can be devastating to our health, causing low-grade inflammation, coming from proinflammatory cytokines.
Inflammation in the brain causes changes in the brain, particularly within our interoceptive network, reducing its ability to accurately regulate our body budget, making it more likely that our budget will remain overdrawn. A chronically imbalanced body budget acts as a fertilizer for different kinds of diseases, such as diabetes, heart disease and even cancer Lisa Feldman says.
Chronic pain seems to be a tragic case of predicting poorly and receiving misleading data from the body.
Our body budgeting regions have tricked our brain into believing that there is tissue damage, even though the tissues/injury have since healed.
The brain issued unnecessary predictions of pain and then ignored prediction error to the contrary. In other words, our brain ignored sensory input maintaining that its predictions are reality.
Overall, Lisa Feldman Barrett's vision on chronic pain underscores the importance of considering the brain's predictive processes, as well as the broader psychological and social context, in understanding and managing pain experiences. Her perspective challenges traditional views of pain as a purely sensory phenomenon and highlights the need for interdisciplinary approaches that integrate insights from neuroscience, psychology, and social science.
Luc Vanderweeën
Senior Master of Science in Physical and Manual Therapy
Pain in Motion International Research Group
2024 Pain in Motion
References and further reading:
If you want to learn more about the fascinating insights of Lisa Feldman Barrett, I can strongly recommend her book:
Barrett, L.F. (2017). How Emotions Are Made: The Secret Life of the Brain. New York, NY: Houghton-Mifflin-Harcourt.
