Title: How we understand our emotions: Is alexithymia following traumatic brain injury a generalised failure of interoception?
Funder: The Academy of Medical Sciences

Abstract: I plan to examine the processes for understanding our emotions and how they go wrong after a TBI. One common example of emotional disturbance after head injury is a state called alexithymia or difficulty understanding one’s own emotions. Emotional and social dysfunction is underinvestigated in traumatic brain injury (TBI). These behaviours are amongst the most frequent and debilitating consequences of head injury for patients and caregivers. Many of the mechanisms that result in the cognitive, emotional and neuro-behavioural consequences of TBI are unclear and poorly defined. We interpret our bodily signals by a process called interoception. Interoception refers to the interaction of physical signals with the brain, generating such diverse states as anger, fear, fatigue and hunger. The signals can be emotional or non-emotional. I want to understand whether there is a fundamental problem with processing all physical signals or a specific problem with processing signals relating to emotion in patients with TBI. I will approach this by assessing brain-body interactions using emotional physiological signals (galvanic skin response) and non-emotional signals (heartbeat at rest). I will be using neuroimaging techniques to correlate impaired sensitivity to bodily signals with changes in grey matter and white matter connections from key hubs that we know are important for interoception; the anterior cingulate and the anterior insula. This approach aims to directly link brain structure and function to behaviour across the spectrum of injury severity. It will provide a framework to understand a broad range of symptoms in TBI.

Lay abstract: Son: ‘I don’t feel anything for the people I love any more. How can that happen?’ Father: ‘I dread going out for drinks with him (son). It just takes one look from a stranger and he becomes very aggressive, totally out of the blue.’ As a neurologist I regularly see patients successfully discharged from hospital after a head injury only to find they are unable to interact as before in society. The consequences include divorce, unemployment or physical aggression. A risk factor for aggression is not being able to understand your emotions. This is called alexithymia and is common after head injury. We normally understand our emotions through a process called interoception. Our brain interprets bodily signals to give them meaning. This allows us to know if butterflies in our stomach is because we are scared or excited. Bodily signals also help our brain understand non-emotional states, for example hunger or tiredness. I want to look at how head injury patients interpret body signals whether they are relevant to emotion or not. This will tell us if the emotional difficulties are because of a general problem with interpreting bodily signals or specific to those related to emotion. I will explore where in the brain that happens. I will do that by looking at the connections coming out of two regions we know to be important for sensitivity to bodily signals. This can tell us if changes after injury can explain the differences seen. Understanding is the first step to treatment.

Research activity codes: 1.2 PSYCHOLOGICAL AND SOCIOECONOMIC PROCESSES;2.3 PSYCHOLOGICAL, SOCIAL AND ECONOMIC FACTORS
Health categories: MENTAL HEALTH