The area of ​​the brain supposed to transmit consciousness behaves more like an internet router

A new study developed a new theory that the brain’s claustrum behaves less like the “seat of consciousness” as previously thought, and more like an Internet router, receiving and broadcasting signals for complex cognitive tasks. The study is published in Trends in cognitive science.

Explore the function of the cloister

The claustrum is a region of the brain located below the cortex. It has long been thought to exchange signals with the cortex, itself an area responsible for coordinating higher processes such as reasoning, memory and complex thought.

renowned scientist Francois Crick – made famous for his role in the discovery of the DNA double helix – suggested in a posthumous publication article in 2005 that the claustrum is the “seat of consciousness”, theorizing its role in our awareness of the world and of ourselves.

However, researchers at the University of Maryland School of Medicine (UMSOM) have proposed that Crick’s theory may be incorrect. In this new study, they posit that the claustrum behaves more like a broadband internet router than the seat of consciousness.

In this example, the claustrum receives direction and commands from the “boss”, i.e. areas of the cortex. The claustrum then organizes and broadcasts these signals, much like a wireless router for an Internet network. Together, the different networks are synchronized and allow us to perform cognitively challenging tasks.

“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,” Explain Dr Brian Mathur, associate professor of pharmacology at UMSOM and lead author of the study. “As the most connected structure in the brain, the claustrum is a window into the enigma of the brain, the mind.”

Knowledge of the coordination of these networks between the cortex and the claustrum is important, because dysregulation of these systems is characteristic of many disorders including schizophrenia, drug addiction and Alzheimer’s disease. Knowledge of these networks and the mechanisms underlying them could lead to more effective therapies for these disorders.

Evidence Against Crick’s Theory of Consciousness

Mathur and his colleagues conducted a series of experiments on animals and humans to try to elucidate the exact role of the claustrum. Using a mouse model, the researchers first demonstrated that “shutdown” of the claustrum did not lead to loss of consciousness, and the mice continued their normal activity.

Next, the mice were given a simple or difficult task to complete. Under normal conditions, mice can successfully perform both simple and difficult tasks. However, the researchers found that when they “turned off” the claustrum, the mice could not complete the difficult tasks.

To determine if these findings could extend to humans, Mathur set up a research study in collaboration with colleagues. David Seminowiczprofessor of neural and pain sciences at the UM School of Dentistry, and Fred Barretteassociate professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine.

The study looked at healthy volunteers undergoing functional MRI (fMRI) brain scans while performing simple or complicated mental tasks. fMRI detects areas of activity in the brain by detecting changes in blood flow. This showed that only complicated tasks caused the claustrum to “ignite”, indicating increased activity. Moreover, this occurred alongside the activation of a network in the cortex associated with cognitive performance.

Together, these findings seem to dispel Crick’s theory of consciousness. Still, Mathur says more experiments are needed to support this new theory of claustrum function and understand how it can organize networks in the cortex to support cognition.

Reference: Madden MB, Stewart BW, White MG et al. A role for the claustrum in cognitive control. TiCS. 2022;26(12):1133-1152. do I: 10.1016/j.tics.2022.09.006

This article is a reprint of a Press release issued by the University of Maryland. Material has been edited for length and content.