Keeping the body in mind: The role of interoceptive awareness in emotion recognition in dementia syndromes and healthy populations

Abstract

Despite the importance of emotion recognition in social interactions, the mechanisms underlying this ability are unclear. Interoception is the ability to recognise and respond to internal body signals, such as heart rate or breathing. Interoception is theorised to be involved in emotion. Dementia syndromes with unique patterns of brain atrophy represent an opportunity to establish a shared neural basis of interoception and emotion. Study 1 identified disease specific mechanisms underlying emotion recognition impairments in three dementia syndromes. In behavioural-variant frontotemporal dementia (bvFTD, n = 52), worse cardiac interoception predicted lower emotion recognition. Whereas emotion recognition difficulties were better explained by cognitive impairment in Alzheimer’s disease (AD, n = 41) and Parkinson’s disease (PD, n = 24). Neuroimaging analyses revealed shared neural correlates for interoception and emotion recognition in the left insula, orbitofrontal cortex, and amygdala in bvFTD only. Study 2 investigated interoception and emotion in semantic dementia (SD), due predominately left-lateralised (left-SD) or right-lateralised (right-SD) anterior temporal lobe and insula atrophy. Right-SD (n = 6) showed worse interoception than both left-SD (n = 8) and healthy controls (n = 21). Neuroimaging analyses revealed shared neural correlates for interoception and emotion in the right insula, temporal pole, and hippocampus. Study 3 explored interoceptive attention could enhance emotion recognition as a proof-of-concept study. No differences in subsequent emotion recognition were observed after focusing on cardiac or respiration sensations. Greater cardiac interoceptive accuracy, however, predicted higher emotion recognition performance. Overall, this thesis furthers our knowledge of interoception and emotion and directs future research to target the interoception as an underlying disease mechanism, as well as a potential early biomarker of bvFTD and right-SD.