Bodily beliefs: Discovering the neurocognitive origins of somatic symptoms

Where do symptoms come from? We usually assume a bodily symptom originates from tissue pathology, but our subjective experience of a symptom reflects both peripheral physiological signals and neurocognitive processes. This is exemplified in the case of 'medically unexplained' somatic symptoms, which are common, disabling, and costly, accounting for 10% of NHS expenditure for the working-age population. My research investigates how expectations in the brain interact with the body's internal environment to generate somatic symptoms. In the first stream ('Somatosensory Expectations.') I develop an experimental model of conditioned somatosensory symptoms, using computational modelling to reveal how expectations alter bodily experience and their role in clinical somatic symptoms. In the second stream ('Appetitive Internal Expectations.') I use flavour-calorie conditioning to investigate metabolic reward learning and prediction error, testing whether disrupted expectations of internal appetitive reward might drive somatic symptoms in depression. In the third stream ('Aversive Internal Expectations.') I investigate whether signals from the gut to the brain also drive expectations of an aversive internal state, learned disgust avoidance, a transdiagnostic behavioural phenotype. Together, my work will reveal how neurocognitive mechanisms generate symptom experience inside and outside the body, yielding novel insights into the common origins of mental and physical health.