Is there a relationship between the Insula and Mindfulness? One of the core tenets of Mindfulness is to heighten conscious awareness of the body in order to relate better with oneself and with the world in general. In general terms, it is similar to the core concepts on Cognitive behavior therapy, which indicate that you may look after yourself better and relate better with the world at large when you optimize cognition of yourself and of the environment around you.
Perhaps it is not surprising that there is a specific place in the brain that appears to centralize a significant portion of this process: the insula. In the figure, from Johanes Sobotta 1908 anatomy book, available in Wikipedia, it is clear that the name of this structure is appropriate. It is an island of cortex in the middle of white matter between the depths of the frontal and temporal lobes.
It is one of the older human cortices, such as other areas of the Lymbic System, cingular and parahippocampal cortices. Instead of the usual 6 layers of neurons typical of the more modern neocortex of human and higher primates , which covers the surface of the brain, these evolutionary older cortices have 3 or 4 cellular layers.These older parts of the brain were added during evolution of mammals, on top of the brainstem and basal ganglia, which are present in lower vertebrates such as birds and alligators. Then came the 6-layered neocortex of humans and higher primates, and covered everything, leaving the insula, hippocampus and cingulate buried on top of the brainstem and basal ganglia.
Functional neuroimaging studies have shown activity in the insula when the person attends to his or her own thirst, heartbeat, distension of the esophagus, bladder or rectum. Lesions of the right insula have been associated with loss of the sense of body ownership that is necessary for self-agency. The insular cortex is activated by sensations of disgust, fear, happiness, sadness and sexual arousal. The anterior insula is closely related with the anterior and midcingulate cortex in the empathy network which is engaged when people experience emoticons from observing others, as used in the Theory of Mind network.
Eduardo E Benarroch. Insular cortex. Neurology 2019, 93:932-938
The Insular cortex is, accoring to studies in monkeys and humans, where people feel what is going on within themselves, grade its quality, and deliver appropriate reactions that are then executed by other regions of the brain. It regulates blood pressure, heart rate, to the extent that it has been proposed that output from the right insula is sympathetic, and from the left parasympathetic. There is multimodal sensory representation in the insular cortex, from internal organs, with gustatory, olfactory, vestibular, visual and auditory information.
The posterior insula is connected with the parietal and posterior temporal regions; the anterior insula with cingulate, frontal, orbitofrontal and anterior temporal regions. The posterior insula is mainly related with sensorimotor processing; the dorsal anterior mainly with cognitive processing; the ventral anterior with affective limbic áreas. In the anterior insula, in the part related to the frontal and cingular regions, are located the spindle ou so-called von Economo neurons, which exist in large quantities in cetaceans and humans, a less so in the great apes and elephants.
Perhaps because it is a hub for multiple cortical networks involved in emotion, social awareness, behavioral control, cognition and multimodal sensory processing, the insula is involved early on in many degenerative diseases such as Lewy-body demential, frontotemporal dementias, Parkinson’s and Alzheimer’s diseases.
Dr Paulo Bittencourt