Why is the insula the most interesting region in the brain? Here are 6 things worth knowing. This is topic #3 for our lab's Friday 'Ode to Neuroanatomy' series.
Insula is Latin for island, which connotes detachment & isolation. It was a botched naming job in some respects, as the insula is an exceedingly well connected anatomical hub.
It has access to multi-modal sensory information to monitor the environment and the most comprehensive interoceptive map of the body, placing it in a powerful position to dynamically map environmental contexts to body states (real or simulated) and guide behavior accordingly.
#1) Boundaries: It is buried beneath the Sylvian fissure. The cortex overlying it is referred to as opercular cortices, temporal, frontal, & parietal operculum. It is bounded by the circular sulcus, and the extreme capsule is the white matter underneath.
#2) Main Division: Anterior and posterior insula is divided by the central sulcus. The postero-superior portion is the most granular (most dense layer IV, receives sensory afferents) with a gradient to the antero-ventral portion that is agranular.
#3) Anterior Division: The dorsal anterior insula is a core node of the cingulo-opercular \ action motor network. It has a strong functional connection to the dorsal ACC. A fantastic article on that network by @ndosenbach here: dosenbachlab.wustl.edu/media/papers/A…
#3 cont. The ventral anterior insula (red) is a core node of the salience network and it has a strong functional connection to the rostral ACC. Insular Von Economo neurons live here. An excellent article on the salience network by Bill Seeley is here: pubmed.ncbi.nlm.nih.gov/31676604/