Dorsal Anterior Insula Connectivity — A Potential Target for Cognitive Improvement in MS Patients

“The role of the anterior insula as a critical region regulating switching between cognition and behavior is only just beginning to be investigated and understood,” said presenter Bernardo Canedo Bizzo, MD, research fellow in radiology, Harvard Medical School/Massachusetts General Hospital (MGH), at RSNA 2016.

He added, “The ability to predict possible cognitive deficits based on our functional neuroanatomic findings has the potential to help guide patient management and patient counseling in the future.”

Cognitive impairment is estimated to occur in 40 to 60 percent of MS sufferers. Dr. Bizzo and his team assessed whole-brain, dorsal anterior insula intrinsic functional connectivity using resting state functional MRI (fMRI) in 28 MS patients. In addition, each patient was assessed for cognitive status, degree of disability and cognitive reserve.

They sought to relate dorsal anterior insula instrinsic functional connectivity with measures of cognitive status and reserve. The study provided support for recent findings that relate the insula to a tripartite framework of cognition, emotion and interoception — the sensory system responsible for detecting the body’s internal regulation responses.

The researchers performed 3T MRI using the Connectome scanner at MGH Martinos Center for Biomedical Imaging. The scanner maps white matter connections in the brain by tracking the movement of water and produces higher quality images than conventional MRI in a fraction of the time.

The team used the data they collected to look at the relationship of the dorsal anterior insula and its functional connectivity to the cognitive deficit presented by the patient. They found a significant correlation between cognitive reserve and left dorsal anterior insula instrinsic functional connectivity to an occipital cluster in the left hemisphere of the brain which included the cuneus and superior occipital gyrus.

“This combination of advanced hardware with cutting edge computational tools is especially timely and important given the NIH’s blueprint for ‘The Human Connectome Project: Mapping Structural and Functional Connections in the Brain’, as well as the White House Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative,” Dr. Bizzo said.

According to Dr. Bizzo, he and his fellow researchers sought to ensure that their methods of analysis did not result in an increased number of false positives associated with some commonly used fMRI methods. After their initial review, they reanalyzed the complete dataset using a more conservative approach. Doing so, they confirmed their initial findings and were able to more precisely define the anatomical regions independently related to cognitive reserve in patients with MS. He said, “On our re-analysis it became clear that the occipital region was, without doubt, a strong predictor of cognitive reserve.”

The team plans additional exploration of this topic and will write a review paper on anterior insula function in the hope of raising awareness and generating further research. In addition, they plan to perform a more detailed structural connectivity mapping of the anterior insula specifically in MS using their diffusion spectral imaging dataset.