What is the cognitive footprint of insular glioma?

Abstract

Cognitive impairment has a profound deleterious impact on long-term outcomes of glioma surgery. The human insula, a deep cortical structure covered by the operculum, plays a role in a wide range of cognitive functions including interceptive thoughts and salience processing. Both low-grade (LGG) and high-grade gliomas (HGG) involve the insula, representing up to 25% of LGG and 10% of HGG. Surgical series from the past 30 years support the role of primary cytoreductive surgery for insular glioma patients; however, reported cognitive outcomes are often limited to speech and language function. The breath of recent neuroscience literature demonstrates that the insula plays a broader role in cognition including interoceptive thoughts and salience processing. This article summarizes the vast functional role of the healthy human insula highlighting how this knowledge can be leveraged to improve the care of patients with insular gliomas.

Keywords: brain tumor surgery; cognition; connectomics; functional outcomes; insular glioma.

Figure 1

(A) Surgical anatomy of the insulo-sylvian region relative to an insular glioma. (B) Healthy human insula with associated microvasculature and functional topography.

Figure 2

Non-Traditional Eloquent Networks (NTENs) and associated white matter tracts. The central executive network (CEN) consists of hubs in posterior parietal cortex (PPC) and dorsolateral prefrontal cortex (DLPFC). The arcuate fasciculus (AF), superior longitudinal fasciculus (SLF), inferior fronto-occipital fasciculus (IFOF), and frontal aslant tract (FAT) are the major associate bundles of the CEN. The default mode network (DMN) consists of nodes in anterior and posterior cingulate, lateral parietal cortex, precuneus, ventral medial prefrontal cortex (VMPFC), and anterolateral middle temporal cortex. The cingulum bundle and U fibers provide the majority of white matter connections between DMN hubs. The salience network (SN) consists of hubs in the anterior insula, frontal operculum, dorsal prefrontal cortex, and anterior cingulate cortex. The FAT is the major white matter tract of the SN.