Friday, January 15, 2010
Star Shaped Cells Strengthen Synapses
A new article out this week in Nature adds to the growing evidence for the importance of glial cells in the brain. (Here's the coverage at The Scientist). I've posted before about the myth that we only use 10 percent of our brains, where, I cited as one of the possible origins of this myth, the fact that only about 10 percent of our brain is comprised of neurons and the other 90 percent is made up of these other cell types, collectively called glia. Another idea that I have posted about is the Neuron Doctrine, which is the long held belief in neurobiology that most, if not all of the functions of the brain are the result of neuronal signaling (neurons firing action potentials and transferring those impulses across synapses using chemical neurotransmitters). When both of these ideas are taken together, one can mistakenly get the idea that we only use 10 percent of our brains. While I don't mean to beat a dead horse here, I do like to point out whenever new evidence shows how glial cells are critical to many of the processes that were previously thought to be exclusively neuronal. Along those lines, this new article describes how astrocytes (a sub-type of glial cells that happen to be somewhat star-shaped) play an important (and possibly even necessary) role in strengthening the synaptic connections between cells in a process called long term potentiation (LTP). LTP is thought to be the main mechanism by which new neuronal circuits are established and things like learning and memory are accomplished at the cellular level. Thus, glial cells continue to demonstrate how important they are, even in higher cognitive functions.