Brain claustrum behaves more like a high-speed internet router, study finds

Beneath the outer, wrinkled cortex of the brain lies a deeply mysterious area known as the claustrum. This region has long been known to exchange signals with much of the cortex, which is responsible for higher reasoning and complex thought. Due to the cloister’s extensive connections, legendary scientist Francis Crick, PhD, famous for the discovery of DNA, first postulated in 2005 that the cloister is the seat of consciousness. In other words, the region of the brain allowing awareness of the world and of ourselves.

Researchers at the University of Maryland School of Medicine, however, now posit that Crick may have been wrong: They developed a new theory -; built on data -; that the claustrum behaves more like a high-speed internet router, taking executive commands from “boss” areas of the cerebral cortex that form complex thoughts to generate “networks” in the cortex. Acting like a router, the claustrum coordinates these networks to work together to accomplish the many cognitively demanding tasks we perform every moment of daily life.

Understanding how the brain forms and coordinates these networks in the cortex via the claustrum is important because disorganized networks are a typical feature of many disorders, such as drug addiction, Alzheimer’s disease, and schizophrenia. This insight may help lead to better therapies to treat cognitive dysfunction in these disorders.

“The brain is the most complex system in the known universe. It is these data-driven theoretical advances that propel our knowledge toward harnessing this complexity to improve human life,” said Brian Mathur, PhD, associate professor of pharmacology at UMSOM. “As the most connected structure in the brain, the claustrum is a window into the enigma of the brain, the mind.”

Their new findings and hypotheses were published on September 30, 2022 in Trends in cognitive science.

In an effort to identify the precise role of the claustrum, Dr. Mathur and his colleagues conducted a series of experiments on animals and humans. One experiment used modern neuroscience approaches to disable the claustrum in conscious mice. These mice did not lose consciousness and continued to run normally. A blow against the theory of Crick!

Next, the researchers gave mice a simple or cognitively difficult task and compared how they reacted when the claustrum was turned off. Normally, a mouse can perform both simple and difficult tasks. Yet when the researchers turned off the claustrum, the mice could no longer perform the difficult task.

Wondering if this finding had any relevance to humans, Dr. Mathur collaborated with colleagues David Seminowicz, PhD, professor of neural and pain sciences at the UM School of Dentistry, and Fred Barrett, PhD, associate professor of Psychiatry and Behavioral Sciences at Johns Hopkins University School of Medicine. The three organized a research study where they performed functional MRI brain scans on healthy volunteers who were engaged in simple or complicated mental tasks. The researchers observed that their claustrum only “lit up” when performing the hard version of the task. This event coincided with the activation of a network in the cortex involved in optimal cognitive performance. Hit two against Crick’s Theory of Consciousness!

Dr. Mathur said strike three will occur when additional experiments support their theory of claustrum function. In doing so, Dr. Mathur and his colleagues are now seeking to understand how the claustrum learns and adapts to orchestrate networks in the cortex to help support cognition.

Understand how the brain flexibly forms and coordinates these networks -; through the claustrum -; is essential for treating cognitive decline, which occurs in drug addiction, Alzheimer’s disease and schizophrenia.”

Mark T. Gladwin, MD, Vice President of Medical Affairs at the University of Maryland, Baltimore and John Z. and Akiko K. Bowers Professor Emeritus and Dean of UMSOM

Dr. Mathur added: “Our hypothesis provides us with an indispensable conceptual framework for designing new therapeutic strategies.”