The Salience Network: A Neural System for Perceiving and Responding to Homeostatic Demands

Abstract

The term "salience network" refers to a suite of brain regions whose cortical hubs are the anterior cingulate and ventral anterior insular (i.e., frontoinsular) cortices. This network, which also includes nodes in the amygdala, hypothalamus, ventral striatum, thalamus, and specific brainstem nuclei, coactivates in response to diverse experimental tasks and conditions, suggesting a domain-general function. In the 12 years since its initial description, the salience network has been extensively studied, using diverse methods, concepts, and mammalian species, including healthy and diseased humans across the lifespan. Despite this large and growing body of research, the essential functions of the salience network remain uncertain. In this paper, which makes no attempt to comprehensively review this literature, I describe the circumstances surrounding the initial discovery, conceptualization, and naming of the salience network, highlighting aspects that may be unfamiliar to many readers. I then discuss some of the key advances provided by subsequent research and conclude by posing a few of the questions that remain to be explored.

Figure 1.

The human salience network (A), topography of the VENs (B), and the atrophy pattern in bvFTD (C) strongly overlap. D, A homologous network is elicited by injecting adeno-associated virus (AAV) into mouse prelimbic area (area PL), which produces layer 5 labeling in area ventral anterior insula area (AIv), as well as in the ventral striatum, dorsomedial thalamus (TH), hypothalamus (HT), and central amygdala (CeA). A, Map adapted with permission from Seeley et al. (2007b). B, Map is rendered by the author. C, Map adapted with permission from Perry et al. (2017). D, Map assembled using the Allen Mouse Brain Connectivity Atlas.