Insula sub-regions across the psychosis spectrum: morphology and clinical correlates

Abstract

The insula is a heterogeneous cortical region, comprised of three cytoarchitecturally distinct sub-regions (agranular, dysgranular, and granular), which traverse the anterior-posterior axis and are differentially involved in affective, cognitive, and somatosensory processing. Smaller insula volume is consistently reported in psychosis-spectrum disorders and is hypothesized to result, in part, from abnormal neurodevelopment. To better understand the regional and diagnostic specificity of insula abnormalities in psychosis, their developmental etiology, and clinical correlates, we characterized insula volume and morphology in a large group of adults with a psychotic disorder (schizophrenia spectrum, psychotic bipolar disorder) and a community-ascertained cohort of psychosis-spectrum youth (age 8–21). Insula volume and morphology (cortical thickness, gyrification, sulcal depth) were quantified from T1-weighted structural brain images using the Computational Anatomy Toolbox (CAT12). Healthy adults (n = 196), people with a psychotic disorder (n = 303), and 1368 individuals from the Philadelphia Neurodevelopmental Cohort (PNC) (381 typically developing (TD), 381 psychosis-spectrum (PS) youth, 606 youth with other psychopathology (OP)), were investigated. Insula volume was significantly reduced in adults with psychotic disorders and psychosis-spectrum youth, following an anterior-posterior gradient across granular sub-regions. Morphological abnormalities were limited to lower gyrification in psychotic disorders, which was specific to schizophrenia and associated with cognitive ability. Insula volume and thickness were associated with cognition, and positive and negative symptoms of psychosis. We conclude that smaller insula volume follows an anterior-posterior gradient in psychosis and confers a broad risk for psychosis-spectrum disorders. Reduced gyrification is specific to schizophrenia and may reflect altered prenatal development that contributes to cognitive impairment.

Identification of texture MRI brain abnormalities on first-episode psychosis and clinical high-risk subjects using explainable artificial intelligence

“…In other regions such as the insular or cingulate cortex, gray matter loss in CHR-T has also been reported to exceed that of CHR_NT [ 75 ]. The structural alterations reported in previous studies are in line with the identified regions in the current analysis, such as temporal regions [ 76 ]; frontal cortex [ 77 – 79 ]; thalamus [ 72 ]; insula [ 80 ]; hippocampus and caudate nucleus [ 81 , 82 ]; pallidum, putamen [ 83 ]; parahippocampus [ 83 , 84 ]; and lingual cortex [ 85 ]. White matter: There is accumulating evidence of compromised white matter function leading to abnormalities in synchronization and connectivity in patients with schizophrenia [ 86 ], the most widely used measure being fractional anisotropy (FA) assessed with diffusion tensor imaging (DTI).…”

Insula volumes in first-episode and chronic psychosis: A longitudinal MRI study

“…In contrast, in our sample, we explored both the anterior and posterior insula, highlighting a different pattern of increased and decreased GM modification, as also reported by a recent study on SCZ (Tian et al, 2019). Interestingly, our results seem in line with a recent study suggesting a different involvement of insular subregions and a differential association of these subregions to both clinical and cognitive aspects in psychotic patients (Sheffield et al, 2021). Although the causes of this differential alteration of insular GM are not easy to draw, some possibilities may be considered in the context of the existing literature showing that anterior and posterior insula are part of different networks subserving different functions (Li et al, 2019).…”

Acculturative orientations among Hispanic/Latinx caregivers in the ABCD Study: Associations with caregiver and youth mental health and youth brain function

“…We showed that this is indeed the case among ABCD Hispanic/Latinx families, as youth of caregivers with a bicultural orientation exhibited significantly lower somatic complaints and depression. In terms of neural differences, youth of bicultural caregivers exhibited greater rs-fMRI activity (both fALFF and ReHo) in the left insula, potentially indicating increased metabolic rate of glucose and oxygen (64); these results are aligned with studies showing the insula is associated with somatic and depressive symptoms (65,66) and psychopathology broadly (67–69). The current person-centered analyses examining youth differences across caregivers profiles likely captured robust effects across a complex range of family environmental factors.…”