- the main cell of the nervous system. Neurons are responsible for quickly transmitting electrical

impulses to all parts of our bodies, making our muscles contract and returning information

about our environment to our brains. But did you know neurons are far out-numbered in your

brain by another type of cell called glia? By the late 1800s science had advanced enough

to look closely at the cellular structure of the brain. Camillo Golgi, an Italian physician

and soup strainer aficiando, discovered a now famous staining technique that made neurons

visible under the microscope. We could now clearly see the cell body and the axon - the

fibre that conducts electrical impulses over long distances. But Golgiís stain also revealed

something else - cells that looked like tiny spiders throughout the brain. They surrounded

the larger cell bodies and axons of neurons. The cells were called glia, but what they

did was a mystery. Neurons, in contrast, were quickly developing a reputation as the fundamental

unit of the nervous system. 100 years before fellow pizza lover Luigi Galvani had demonstrated

the link between electrical currents and muscle contraction. He took a dead frog and attached

electrodes to itís legs. When current flowed through the electrodes the dead frogs legs

twitched as if theyíd come back to life. Now after the discovery of neurons, another

piece of the puzzle had fallen into place. These cells must form the wires that transmit

electrical signals in our bodies causing our muscles to contract. But what role did that

leave for the glial cells? With Golgiís staining techniques, we could see that glia were much

smaller and clustered around neurons. They appeared to insulate neurons and provide structural

support. In fact this is how they got their name. Glia is Greek for glue, so glial cells

were thought of as the sticky stuff that holds groups of neurons together. Nearly 90% of

the cells in our brains are glia --the other 10% are neurons. This is partially what led

to the myth that we only use 10% of our brains. For over 70 years the neuron dominant view

of brain function went unchallenged. But recent research indicates glia may be much more important

than just glue. Neuroscientist Andrew Koob believes that glia are the 'Root of all Thought'.

He writes that as you move up the evolutionary ladder, the percentage of glia in brains increases

with our definition of intelligence. The brain of a fruit fly is 20% glia, a mouse 60%, a

chimpanzee 80% and a human, 90%. This rather strongly suggests that glia are more than

just glue. Recent research has found that glial cells play a number of critical roles

at synapses, structures that let neurons communicate with each other. At the synapse, glia can

either promote the transfer of a message, or slow activity if the synapses are becoming

overactive. Glia control this transfer of information in brain structures like the hippocampus,

our memory centre. So these tiny cells are affecting how we process information, learn

and memorise. More research has found that glia have stem cell potential, they can guide

neural growth in the developing nervous system. Theyíre kind of like parents, they nurture

young neurons and step back as they grow up. But if the neurons get into trouble, theyíll

step in to help. If nerves get damaged, a type of glial cell called a Schwann cell can

regress to an earlier developmental state to encourage regrowth of the axon. To do this,

they form a type of tunnel that leads towards the target neurons. The stump of the damaged

axon is able to sprout out of the tunnel and can then reconnect with the muscles or organs

they previously controlled. Research into glia is pretty recent and neuroscientists

still have questions about how glia fit into the mix. They could lead to nerve repair and

even be the root of our thoughts. The answers to these questions all lie inside your head.

I just wanted to pop in and say Happy Holidays! If youíre looking for something to read over

the break, this video was inspired by Andrew Koobís book ëThe Root of Thought: Unlocking

Glia--the Brain Cell That Will Help Us Sharpen Our Wits, Heal Injury, and Treat Brain Diseaseí

Itís really interesting AND his name spelt backwards is ëbookí, which is a wonderful

anadrome like snoops and spoons or straw and warts. Thereís a link in the description.

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