How Do Our Brains Puppeteer Our Bodies?
Our brain is generally seen as the headquarters of our body. We have heard time and time again that we should always protect our brain by wearing a helmet while riding a bike. We should make sure we drink enough water and eat enough food so that the brain is well-nourished. Our brain controls our every move, our thoughts, and the way our body regulates itself. Despite all of these complex tasks, our brain weighs only about 2% of our body-weight yet uses up approximately 20% of our energy. 1 But what does our brain do with all of this energy? And how does it communicate with the rest of the body and tell it what to do?
Your brain and spinal cord, also known as the central nervous system, work together to coordinate body functions and responses, like motor or sensory actions (such as picking up a pencil). 2 The central nervous system then communicates with the rest of your body through a special type of cell called neurons.
Neurons are like the strings on a puppet and your brain is like the puppeteer. Let’s say the puppeteer (your brain) wants to move your left arm. First, the puppeteer needs to pull on the string and then your left arm moves. Similarly, your brain communicates to your left arm via neurons that send signals telling it to either flex or relax your arm muscle, causing movement.3 The time it takes for the brain to communicate via neurons to make these movements is almost instantaneous.
One way neurons communicate is through electrical messages, called action potentials.4 An action potential will be sent when the neuron has reached a specific electrical threshold.5 The message is only sent at this threshold. After that the neuron releases neurotransmitters to connect with the next neuron at an empty space between the two, called the synapse.6
Some neurons also have features which allow action potentials (the messages) to travel through them very quickly. Neurons can either be myelinated or unmyelinated. This means that the part of the neuron which sends messages, called the axon, can either be wrapped in myelin sheaths with little breaks in between or not have these wrappings at all. A myelinated neuron would look like a wire, wrapped in an insulation-like material, with small gaps of exposed wire in between the sections of insulation.
Myelinated neurons can send messages faster than unmyelinated neurons because of the chemical properties of the axon at the little breaks. 7 It allows the action potentials to appear as if they are jumping between the wrappings rather than traveling the whole length of the axon. 8 In reality, the messages do in fact travel the whole axon, but they go faster at the breaks in the myelin. This results in faster communication speeds. However, since there are no gaps in an unmyelinated neuron, the messages travel the same speed over the whole axon, resulting in slower communication.
The signals sent and received between neurons is what makes your arm and other parts of your body move. All of these tasks require energy and nutrients, which is why it is important to make sure your brain gets enough rest, food, and water. When your brain is kept healthy, it acts super quickly. But sometimes when an even faster response is needed, like moving your hand away from a hot stove, your spinal cord steps in instead and controls the puppet strings - your brain just gets the memo later that something happened.
Hartmann, P., A. Ramseier, F. Gudat, M. J. Mihatsch, W. Polasek, and C. Geisenhoff. “Normal Weight of the Brain in Adults in Relation to Age, Sex, Body Height and Weight.” Der Pathologe 15, no. 3 (June 1, 1994): 165–70. https://doi.org/10.1007/s002920050040.
Stangor, Charles, and Jennifer Walinga. “Our Brains Control Our Thoughts, Feelings, and Behaviour.” Chapter. In Introduction to Psychology. Accessed February 10, 2024. https://opentextbc.ca/introductiontopsychology/chapter/3-2-our-brains-control-our-thoughts-feelings-and-behavior/.
Stangor, “Our Brains Control”.
Betts, “The Nervous System”.
Betts, “The Nervous System”.
Betts, “The Nervous System”.
Betts, “The Nervous System”.
Betts, “The Nervous System”.