AbstractInteroception refers to the afferent signalling, central processing and neural and mental representation of internal (visceral) bodily signals. Interoceptive signals are integrated by a set of cortical and sub-cortical regions, namely insula, cingulate cortices and amygdala, to regulate autonomic control and guide emotional experience. Autism Spectrum Conditions (ASCs) are a set of neurodevelopmental conditions characterised by altered sensory sensitivity and difficulties with social communication and interaction. ASC individuals may present with an altered interoceptive profile that could contribute to atypical emotional experiences in this population. Emerging work implicates interoceptive differences in the manifestation of anxiety in autistic individuals. This thesis thus aims to better quantify the interoceptive profile of autistic adults, using a combination of behavioural, physiological and neuroimaging techniques, and seeks to better understand how interoceptive signals may contribute to atypical emotional processing and, finally, aims to establish the usability of a novel interoceptive training paradigm to mitigate anxiety in this population.
In the first study, I found that increased interoceptive insight (confidence-accuracy correspondence) mitigated emotional recognition difficulties from the intonation of speech (affective prosody). This suggests that a reduction in consciously perceived interoceptive signals may contribute to atypical emotional processing and social interaction in autistic adults. In a second study, autistic adults
did not differ from non-autistic adults when processing emotional (fear) faces but did show reduced activation and functional connectivity of regions involved in interoceptive and autonomic control, namely right insula cortex, during systolic cardiac signalling suggesting a dysregulated interoceptive system that may contribute to the manifestation of anxiety. In a more targeted study employing an
interoceptive task during functional MRI scanning, I showed significant group differences in functional connectivity of insula cortices across distinct dimensions of interoception (accuracy and insight), despite no group differences at the behavioural level. In the application of a novel interoceptive training paradigm, I found interoceptive training significantly increased interoceptive accuracy and functional connectivity of insular cortices, and, in a parallel investigation, interoceptive training subtly enhanced intensity ratings towards emotional faces. Finally, in the application of a novel exteroceptive training paradigm (affective prosody), I found training enhanced affective prosody recognition but did not impact interoceptive dimensions. Together, these findings elucidate the altered interoceptive profile of autistic adults and demonstrate how cardiac interoceptive signals influence emotional experience in this population. Finally, they show how interoceptive and exteroceptive training paradigms can increase emotion sensitivity in this population, which has important clinical implications for mitigating emotional and social difficulties in autistic adults.
|Date of Award
|Sarah Garfinkel (Supervisor)