Neurons – a brain superhighway!

Single Living Neuron

Figure 1: A black and white picture of a single living neuron. Two dendrites, the cell body, and the axon are labelled. The electrical signals from this neuron were being recorded through a glass electrode.

Neuron morphology and function

By Dr. Jenna Koschnitzky, Research Programs Manager

In your brain, neural networks = your personal computer circuit. Your brain is like a computer – except much more complex, dynamic, and adaptive. Neural networks are composed of individual cells called neurons which quickly transmit information throughout the brain and spinal cord using electrical signals. Neurons tell your muscles when to contract, tell your brain when you are in pain or being tickled, preserve your memories, and allow you to think in general.

Neurons are composed of 3 main compartments: dendrites, a cell body, and an axon. Dendrites receive information from other neurons and then transmit that information to the cell body. The cell body consolidates the information and can then trigger a strong electrical signal down the axon. Once the electrical signal reaches the end of the axon, the information is transmitted to either another neuron or a muscle fiber. In most cases, the information hops from one neuron to another using a chemical synapse.

If you have a simple network of 2 neurons, the neuron that sends the information is the pre-synaptic neuron. The neuron that receives the information is the post-synaptic neuron. We say that the pre-synaptic neuron innervates the post-synaptic neuron.

Post-synaptic Neuron

Figure 2: Diagram of a pre-synaptic neuron innervating a post-synaptic neuron. Information flows from the pre-synaptic neuron to the post-synaptic neuron through a chemical synapse.

Some neurons transmit information locally, but others have extremely long axons. To transmit information quickly, specific types of glial (support cells) surround the axon. In the central nervous system, these glial cells are called oligodendrocytes. The oligodentrocytes create a myelin sheath around axons that insulate the axon and allow the electrical signal to propagate more efficiently. In the peripheral nervous system, Schwann cells produce myelin.

Without myelin, it would take up to 2 seconds for a signal to travel from your spinal cord down to the muscles in your foot. At that speed, you would move more like a zombie (the old ones that do not run)!  Myelin reduces that time to 6 milliseconds or 0.006 seconds!

Bringing it back to research…

Neurons make up the networks that allow the brain to function. In Basic Science research, we’re discovering how neurons and the other basic components of your brain function. So when you see a research study under the category of Basic Science, these studies are critical because, without an understanding the basic functions of the brain, researchers can’t go on to figure out better or different treatment options and cures.