Structural and functional exploration of insula in severe alcohol use disorder: An investigation of interoception and craving neural signature
Creators: name: Billaux, Pauline
name: Billieux, Joel
name: Maurage, Pierre
name: Desmedt, Olivier
Publisher: name: OSF Registries
Year: 2024
Subjects: subject: Cognitive Neuroscience
subject: Psychiatry and Psychology
subject: Medicine and Health Sciences
subject: Life Sciences
subject: Biological Psychology
subject: Neuroscience and Neurobiology
subject: Social and Behavioral Sciences
subject: Psychology
subject: FOS: Psychology
subject: craving
subject: functional neuroimaging
subject: insula
subject: interoception
subject: severe alcohol use disorder

description: Major models have theorized insula key role in addiction (e.g., Noël et al., 2013), notably through its processing of interoceptive signals related to craving (Ibrahim &amp; Le Foll, 2023). However, neuroimaging studies differ largely on insular parcellation techniques, thus ending up, notably, with studies reporting insular subdivisions ranging from 2 to 13 anatomical/functional subregions (Centanni et al., 2021), therefore impeding results comparativeness and exactness in humans (Droutman et al., 2013). There is thus a need for refined exploration of insular subregions activation, following anatomical subdivisions of the insula (Droutman et al., 2013). 

Following a refined and detailed anatomical exploration of insular subregions has however revealed of interest. In a prior study (Billaux et al., 2023), which aimed in exploring the grey matter volume of insular subregions in patients with severe alcohol use disorder, we followed an anatomical parcellation of the insula in six right and six left subregions (Faillenot et al., 2017). Rationale for using this specific insular parcellation is that, by combining both macro-anatomical landmarks and probabilistic techniques, this parcellation based on a probabilistic atlas overcomes prior parcellation limits such as coarse subregions delimitation (i.e., ending up with are fined 6*2 parcellation) while considering between-subject variability (Faillenot et al., 2017). We found an overall shrinkage of sAUD insula and a right-sided lateralization effect but, also, that insular subregions showed a differentiated atrophy profile, with major shrinkage in the posterior insula (i.e., anterior long gyrus) while the rostral insula (i.e., anterior insular cortex) showed limited atrophy. At the functional level, Haruki &amp; Ogawa (2023) – which, also, followed Faillenot et al.’s (2017) insular parcellation – found differentiated patterns of activation of insular subregions in healthy controls (HC). The authors explored whether asking healthy controls (HC) to focus either on their heart or stomach signals lead to differentiated activations of insular subregions. They found that attention to gastric interoceptive signals led to a preferential activation of the left and right posterior insula (i.e., anterior long gyrus) and that the right anterior and middle insula (i.e., anterior and middle short gyri) showed a preferential pattern of activation for attention to cardiac-related interoceptive signals. 

The aim of the current study is to investigate the insular subregions activation related to cardiac and gastric-related interoceptive attention tasks – as priorly done in HC in Haruki &amp; Ogawa (2023). In addition, we would like to explore whether sAUD patients show differentiated profiles of insular subregions activation from HC. Moreover, we aim to explore insular subregions activation when participants are asked to remember physical and cognitive/psychological sensations related to craving (i.e., thoughts related to the desire to consume a substance). While craving is conceptualized as being underpinned by cognitive/psychological processes (Kavanagh et al., 2013), theorizations of insula as a craving neural substrate is in fact related to its role in processing information related to the bodily effects of the substance (Noël et al., 2013). Therefore, in the current study, we would like to explore whether processing bodily-related or cognitive-related sensations of craving leads to differentiated pattern of insular subregions activation but, also, whether group differences emerge in the processing of such sensations.