Structural connectivity profile supports laterality of the salience network

Abstract

The salience network (SN) is mainly involved in detecting and filtering multimodal salient stimuli, and mediating the switch between the default mode network and central executive network. Early studies have indicated a right‐sided dominance in the functional organization of the SN; however, the anatomical basis of the functional lateralization remains unclear. Here, we hypothesized that the structural connectivity profile between the frontoinsular cortex (FIC) and dorsal anterior cingulate cortex (dACC), which are two core hubs of the SN, is also dominant in the right hemisphere. Based on diffusion and resting‐state functional magnetic resonance imaging (rfMRI) of adult healthy volunteers in independent datasets, we found a stable right‐sided laterality of both the FIC‐dACC structural and functional connectivity in both the human connectome project cohort and a local Chinese cohort. Furthermore, a significant effect of aging on the integrity of the right FIC‐dACC structural connectivity was also identified. The right‐sided laterality of the structural organization of the SN may help us to better understand the functional roles of the SN in the normal human brain.

Frequency-dependent circuits anchored in the dorsal and ventral left anterior insula

“…An alternative explaination is that the LVAI has more von Economo neurons which project to the ACC forming a basic structure of the SN 29 . Overall, the functional segregation of LDAI and LVAI is supported by their different cytoarchitectures and structural connections 9,29 .…”

“…Although broadband FCs of AI in its entirety show hemispheric lateralization 8 , FCs of the LDAI and LVAI are similar to those of the RDAI and RVAI 12 , 14 . This is incompatible with distinctive functions of the LAI and RAI 8 , 9 . Considering the frequency-dependent functional organization of RAI 7 , it is necessary to differentiate subparts of the LAI in different narrow bands for probing its functional organization.…”

“…Recently, we have demonstrated the frequency-dependent functional organization of the RAI, supporting its unique role in attention-demanding tasks and inter-network orchestration 7 . Due to the lateralization of AI 8 , 9 , the left anterior insula (LAI) has rarely been reported in attention-demanding tasks but has been shown in performing emotion-related tasks such as emotional working memory and decision-making 3 , 10 , 11 . These studies argue that the LAI has different functional organizations from the RAI which is crucial to its cognitive functions.…”

Self-reference Network-Related Interactions During the Process of Cognitive Impairment in the Early Stages of Alzheimer’s Disease

“…This may be related to the laterality. For instance, the significance of network functional lateralization in AD progression is as follows: (1) in the SN, in which right lateralization has been proven (Zhang et al, 2019 ), the occurrence of connections with the SRN on the right side rather than the left side significantly reduced FC, especially in the right prefrontal cortex, and has been observed in subjective cognitive decline patients (Hu et al, 2017 ); (2) however, in the DAN, damage patterns (Zhang et al, 2015 ) and inhibition in the temporal region of the whole brain have been observed in MCI patients (Chand et al, 2018 ; Zhang et al, 2019 ), but evidence for lateralization remains debatable (Corbetta and Shulman, 2002 ; Vossel et al, 2012 ; Mayrhofer et al, 2019 ); and (3) in addition, the DMN also presented left lateralization but functional decline with age and AD (Banks et al, 2018 ), showing insufficient activation in the right prefrontal region but overactivation in the left prefrontal region during memory maintenance and reasoning tasks in MCI patients (Melrose et al, 2018 ). Nevertheless, the hyperactivation in the DAN and SN and the hypoactivation in the DMN were regarded as compensatory due to damage that had been confirmed to be directly related to the AD pathology in the right hemisphere (Wu et al, 2011 ; Li et al, 2012 ).…”

Sex Differences in Salience Network Connectivity and its Relationship to Sensory Over‐Responsivity in Youth with Autism Spectrum Disorder

“…Higher-level group analyses were conducted using FSL's Local Analysis of Mixed Effects State (FLAME 1 + 2). Research examining the SN supports a right dominance, as hubs of the network have been shown to be more connected to regions on the right hemisphere compared to the left [Cauda et al, 2011;Seeley et al, 2007;Zhang et al, 2019] in addition to activating more in response to salient stimuli [Sridharan, Levitin, & Menon, 2008]. Therefore, a 5-mm sphere in the right anterior insula (rAI; Montreal Neurological Institute [MNI] coordinates 38, 26, −10) was used as the seed for the SN [Seeley et al, 2007].…”