How does the nervous system communicate with the brain?
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Your body is made up by trillions of cells that do various things, and the cells associated with the Nervous System are called neurons. The human Nervous System can be divided into two components: The Central Nervous System, made up of the Brain (which is inside your head) and the Spinal Cord (inside your spinal column which is your backbone); and the Peripheral Nervous System, composed of various nerves, like Cranial nerves (around your head), and peripheral nerves (that go all around your body). Nerves are bundles of neuronal fibres that transmit signals, which are electric impulses. These signals are transmitted from the periphery, for example, the toe, to the Spinal Cord and the Brain by sensory neurons. Signals can also go the other way around, from the Central Nervous System to the various parts of your body, through motor neurons. Show Now, all over your body you have sensors that detect different types of information. Your eyes, for instance, detect light. All over your skin you have sensors that detect pressure. Your ears detect sound. Also, all over your body you have sensors that detect pain. All these different sensors are neurons that specialise in the detection of different types of information. When these specialised sensors detect something, they generate an electric impulse that is transmitted through a neuronal fibre, bundled in a nerve, all the way to Central Nervous System. This happens extremely fast. Then, in the Central Nervous System, you have specialised groups of different neurons to process the information and generate the appropriate responses. Those responses are then transmitted (as electric impulses) down motor neurons to the muscles. An example of this is what happens when you hurt yourself: for instance when you accidentally prick yourself in the hand, your immediate response is to lift your hand away from the thing that pricked you. This happens because your skin creates a pain signal that travels through sensory nerves to the Central Nervous System, first to the Spinal Cord and then the Brain. Once there, the neurons create a response that travels down motor neurons that communicate with muscles, driving your hand to move away. Core Concepts How Neurons CommunicateRelated Topics Your Complex Brain How Your Brain Processes Information
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3D BrainAn interactive brain map that you can rotate in a three-dimensional space.Interact with the Brain Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs. Neurons are the most fundamental unit of the nervous system, and yet, researchers are just beginning to understand how they perform the complex computations that underlie our behavior. We asked Boaz Barak, previously a postdoc in Guoping Feng’s lab at the McGovern Institute and now Senior Lecturer at the School of Psychological Sciences and Sagol School of Neuroscience at Tel Aviv University, to unpack the basics of neuron communication for us. “Neurons communicate with each other through electrical and chemical signals,” explains Barak. “The electrical signal, or action potential, runs from the cell body area to the axon terminals, through a thin fiber called axon. Some of these axons can be very long and most of them are very short. The electrical signal that runs along the axon is based on ion movement. The speed of the signal transmission is influenced by an insulating layer called myelin,” he explains. Myelin is a fatty layer formed, in the vertebrate central nervous system, by concentric wrapping of oligodendrocyte cell processes around axons. The term “myelin” was coined in 1854 by Virchow (whose penchant for Greek and for naming new structures also led to the terms amyloid, leukemia, and chromatin). In more modern images, the myelin sheath is beautifully visible as concentric spirals surrounding the “tube” of the axon itself. Neurons in the peripheral nervous system are also myelinated, but the cells responsible for myelination are Schwann cells, rather than oligodendrocytes.
“Myelin’s main purpose is to insulate the neuron’s axon,” Barak says. “It speeds up conductivity and the transmission of electrical impulses. Myelin promotes fast transmission of electrical signals mainly by affecting two factors: 1) increasing electrical resistance, or reducing leakage of the electrical signal and ions along the axon, “trapping” them inside the axon and 2) decreasing membrane capacitance by increasing the distance between conducting materials inside the axon (intracellular fluids) and outside of it (extracellular fluids).” Adjacent sections of axon in a given neuron are each surrounded by a distinct myelin sheath. Unmyelinated gaps between adjacent ensheathed regions of the axon are called Nodes of Ranvier, and are critical to fast transmission of action potentials, in what is termed “saltatory conduction.” A useful analogy is that if the axon itself is like an electrical wire, myelin is like insulation that surrounds it, speeding up impulse propagation, and overcoming the decrease in action potential size that would occur during transmission along a naked axon due to electrical signal leakage, how the myelin sheath promotes fast transmission that allows neurons to transmit information long distances in a timely fashion in the vertebrate nervous system. Myelin seems to be critical to healthy functioning of the nervous system; in fact, disruptions in the myelin sheath have been linked to a variety of disorders. “Abnormal myelination can arise from abnormal development caused by genetic alterations,” Barak explains further. “Demyelination can even occur, due to an autoimmune response, trauma, and other causes. In neurological conditions in which myelin properties are abnormal, as in the case of lesions or plaques, signal transmission can be affected. For example, defects in myelin can lead to lack of neuronal communication, as there may be a delay or reduction in transmission of electrical and chemical signals. Also, in cases of abnormal myelination, it is possible that the synchronicity of brain region activity might be affected, for example, leading to improper actions and behaviors.” Researchers are still working to fully understand the role of myelin in disorders. Myelin has a long history of being evasive though, with its origins in the central nervous system being unclear for many years. For a period of time, the origin of myelin was thought to be the axon itself, and it was only after initial discovery (by Robertson, 1899), re-discovery (Del Rio-Hortega, 1919), and skepticism followed by eventual confirmation, that the role of oligodendrocytes in forming myelin became clear. With modern imaging and genetic tools, we should be able to increasingly understand its role in the healthy, as well as a compromised, nervous system. How does the brain interact with the nervous system?Think of the brain as a central computer that controls all the body's functions. The rest of the nervous system is like a network that relays messages back and forth from the brain to different parts of the body. It does this via the spinal cord, which runs from the brain down through the back.
How does nervous system communicate?In both the nervous and the endocrine system signals are passed from one cell to another by chemical communication. In the nervous system, nerve cells send messages electrochemically: this means that chemicals cause an electrical impulse from one cell to another.
How does the nervous system send messages to and from the brain so fast?Myelin insulates the axon and helps nerve signals travel faster and farther. Messages travel along a single neuron as electrical impulses, but messages between neurons travel differently.
Does the nervous system send signals to the brain?What does the nervous system do? Your nervous system uses specialized cells called neurons to send signals, or messages, all over your body. These electrical signals travel between your brain, skin, organs, glands and muscles.
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