There is a gigantic neuron that wraps itself around your entire brain. That’s right – one single neuron, those brain cells that, among other things, generate the bioelectrochemical signals that make you, you.
This neuron is part of a group of three in a so-called “crown of thorns” network. They’re all extremely long and they all emerge from a small, thin layer of cells named the “claustrum.” Admittedly, this has only been confirmed in mice, but the structural similarities of their brains with ours strongly suggests that we have the neural crown too.
Speaking at a gathering of the Brain Research through Advancing Innovative Neurotechnologies (BRAIN, of course) initiative in Bethesda, Maryland, the team from Seattle’s Allen Institute for Brain Science explained the painstaking procedure they used to discover this.
First, they sliced up mouse brain samples, injected individual neurons with a fluorescent dye and traced out the illuminated paths by hand. They then took 10,000 high-resolution, high-precision images of the fluorescing neurons, before using a computer program to generate a 3D rendering of the aforementioned crown of thorns.
These neurons appear to be connected to the sections of the brain that control the processing of sensory information and behavior. As the human claustrum is one of the most densely connected areas of the brain, it suggests that the elongated neurons are significant information highways of some sort.
Lead researcher Christof Koch, president of the Allen Institute, once referred to the cell layer as the “Grand Central Station” of the human brain. It could be the proverbial conductor of the neuronal orchestra, with the crown of thorns acting as its conducting arms.
Could this region of the brain help to explain consciousness? agsandrews/Shutterstock
Previous tests on the claustrum in monkeys revealed that part of it responds more to visual stimuli, whereas part of it responds more to sounds. However, no single section responded to both, which means that the claustrum, whatever it does, has no single, clearly defined role.
A previous experiment on people afflicted by seizures revealed that if a significant electrical current is applied to a small area of the claustrum, the patients’ consciousness is suddenly and severely disrupted. It effectively put their brain in some sort of “standby” mode.
Removing the current brought the patients back around immediately with no knowledge of what just transpired.
In a paper he co-authored with the then-dying Francis Crick, Koch posited that this “superhub of neuronal activity” might be pivotal for our understanding of consciousness. The seizure experiments suggest that he might be on to something.
In any case, claustrum is clearly an unfathomably important region of the brain. The mysterious, newly identified crown of thorns only highlights the importance of finding out what on Earth its function actually is.
[H/T: Nature]
