Chewing, breathing, and other regular bodily functions that we undertake “without thinking” actually do require the involvement of our brain, but the question of how the brain programs such regular functions intrigues scientists.
A team lead by Arlette Kolta, a professor at the University of Montreal’s Faculty of Dentistry, has shown that astrocytes play a key role. Astrocytes are star-shaped glial cells in our brain. Glial cells are not neurons – they play a supporting role. The team’s finding in fact challenges some of the beliefs scientists have about the way our brain works. The brain contains billions of cells and every brain function depends on the ability of neurons to communicate with each other. Neurons use an electrical language to communicate and the pattern of their electrical activity encodes the essence of the message that they convey to the next neuron. “In the neuron-centric vision that dominates at the moment, changes in the pattern of neuronal electrical activity depend solely on the intrinsic properties of neurons and on the information they transmit to one another. Our results demonstrate that glial cells play a crucial role controlling the pattern of neuronal electrical activity and thereby neuronal functions,” Kolta said.
By using different methods to measure the electrical activity of neurons in the trigeminal system which enables sensation in the face and facial motor functions, the researchers were able to look at how the brain processes chewing. “We discovered a mechanism by which astrocytes regulate the extracellular concentration of calcium in this sensory-motor circuit, and by doing this, determine the pattern of electrical activity of surrounding neurons. We think that the trigeminal neurons that we investigate have a dual function depending on the pattern of their electrical activity which can be either tonic or bursting,” explained Philippe Morquette, first author of the study. Tonic is like the hum when you pick up the phone, a continuous and permanent connection to the different parts of the system, while bursting is like the ringing you hear when you finish dialing. Source: Every bite you take, every move you make, astrocytes will be watching you