What is the "spinal cord"?

What is the "spinal cord"?

Les Weiner (Former Chair of the Department of Neurology, University of Southern California) gives expert video advice on: What are the different areas of the spinal cord, and what are their functions?; How does pain work in the nervous system? and more...

The spinal cord has neurons in it that are like weigh stations. Some of the impulses that come in make a connection, and then go up into the brain and make different connections in the regions of the brain. Those that go out, come down and make connections in the spinal cord, they're tracks. So there's gray matter which is where the neurons are that are weigh stations, and then there's the white matter surronding it, which is the tracks. The tracks are eather going up or coming down, depending on where the impulses started. For instance, if I want to write something I pick up my pencil. The motor neurons are getting commands from my cortex to pick up that pencil. The actual contraction of the muscles and the relaxation of other muscles so that you can make a pinch movement, that requires regulation of the motor neurons. The actual writing however requires the motor neurons but it needs direction from the brain. So the impulses are coming down, hitting the motor neurons, and telling us that information. We have to feel the pencil as well. So there are impulses coming from the finger tips going into the spinal cord and then up to the brain as well. So you need the motor movement, but you need the sensory input to tell you that you have a pencil in your hand.