Brain development and learning cognitive processes
Professor Jeff Lichtman describes the process by which our nerve cells compete, which ultimately gives rise to our ability to learn and interact with the environment.
You would probably be surprised to learn that the nervous system does not develop in just a building way. Actually, during the process of making a brain a lot of edifices that are built up are torn down. What finally remains is the strong connections and wiring that is useful for a nervous system and what’s been lost are all connections and cells that tried to be part of your nervous system, but for one reason or another were inadequate, and I think it’s a little hard to think about it this way.
I would like you to imagine that the brain is made up not of a brain, a single organ, but actually made up of many single celled organisms known as neurons. We know that neurons are in the brain that is what the brain is made up of these little cells, but I would like you to imagine these cells as behaving, as being little creatures just like single celled organisms in a pond are single creatures. These are animals that are living in a very weird pond, your mind, your brain, and in that world they have to compete with each other in order to survive. In one wave of competition that takes place before humans are born a substantial number of these nerve cells die; they probably starve to death, they compete with other nerve cells for things called trophic factors or growth factors and there isn’t quite enough of those factors to go around. Some of the nerve cells survive and many of the nerve cells are lost. Of the survivors that make it to the time you are born, there is then a second very serious wave of competition, which has a better outcome, no nerve cell dies after this point but nerve cells have to give up many of the connections they made earlier in life. Nerve cells start out competing with each other by making connections with way too many target cells. Every nerve cell thinks it can do more or less everything and it branches like crazy. Every single one of them branch, every target cell is receiving converging input from many, many different nerve cells and the targets don’t want to be contacted by so many target cells. So the target cells listen to these nerve cells and decide they like some of the nerve cells better than others and they kind of cause these nerve cells to compete with each other to boot off and get rid of some of these connections and leave others, and this phase of pruning has a lot to do with experience.
What we end up being is a lot related to which of those connections are saved and which ones go. The language we speak is not in our genes, the language we speak is in the experience we have as a young person. The tools we use whether we use a keyboard, or a Blackberry, or whatever, an iPod, or whatever is the newest, greatest invention, our brains are not designed to use those machines; our brains have to mold themselves to use them and the kind of plasticity that is used here is a plasticity in which nerve cells compete and some nerve cells maintain their connections and those wires are the circuits that are used to allow us to use these tools and other circuits just go away permanently, and once they're gone it's very hard to do these things later in life. If you ask me to use an iPod or a Blackberry you’ll see I am incompetent, whereas I can use an old fashioned typewriter very well. My kids who were brought up later, their nervous systems were molded in an entirely different way than mine largely by virtue of the fact that they experienced a different world when their brain cells were competing, than when my brain cells were competing.
Cognitive information is encoded in patterns of nervous activity and decoded by molecular listening devices at the synapse. Professor Seth Grant explains how different patterns of neural firing are critical to cognition.