Biological Memories

You wake up in the morning and grab breakfast and some coffee. As you head out the door, you slip on your shoes and tie the laces. How did we even learn to do these things that are now second nature to us? We go about our routines, doing actions we’ve learned without realizing that many other organisms can’t “learn”. This raises the critical question of what exactly is learning and how is our brain organized so that we, the human race, can learn better than all the other organisms on Earth?

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Converse sneakers. Image Credit: Amy the Nurse via Flickr. Licensed under CC BY-NC-ND 2.0.

Learning is the process by which we integrate new knowledge, store new memories, and implement new behaviors. During the process of learning how to tie our shoelaces, we are actually physically altering our brains. To understand more about these changes and what they do, we need to remind ourselves about the basics of brain function.

Neurons are specialized cells located throughout our body that have three basic functions: receiving signals, processing these signals to determine what the neuron should do, and then sending out signals to other cells. The dendrites are where neurons receive and process information. Depending on the signals they receive, they can fire an action potential or have no reaction. The action potential is an excitatory signal that jumps other parts of the neuron into action, including communication channels of the neuron. The communication is mainly via chemical protein messengers called neurotransmitters that are released from the first neuron that triggers a response in the second neuron.

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Neuron. Image Credit: wpclipart.com. Licensed under Public Domain

When you see or do something memorable, it triggers a response in your brain. This response is actually thousands of neurons firing and creating connections at the synapses between them. This response can be triggered by any number of stimuli, including from neurons in your skin as the feel of something you touch to neurons in your visual pathway from something you’ve seen, or signals from receptors in your nose as you smell that coffee in the morning. These are signals that go through an information highway of sorts via your neurons. The message enters the neuron highway at the dendrites at your sensory neurons and travel through the body through these synaptic connections until they reach their exit at the appropriate part of the brain.

Many factors influence the interpretation of this signal, such as the intensity of the stimuli, hormones and neurotransmitters that are present, or even previous experiences with the particular stimuli.

So why is it that you can remember seeing something before or the more that I practice something, the easier it is to do the task? The process of learning and memorization is thought to occur by making new or stronger synaptic connections through reinforcing the strength of existing connections between neurons. There is a common phrase in the field of neuroscience that “neurons that fire together, wire together”. This relates to the more that you tied your shoes, the easier it got. You could remember how to tie your laces quickly without help. What this generally means is that the more often a particular pathway of neurons respond to a certain set of stimuli, the stronger and quicker that response (chemical reactions governed by receptors) occurs. Relating this back to our highway metaphor, the nervous system might shut down specific roads that nobody uses, while adding lanes or faster traffic lights at extremely busy connections. Many recent studies have shown that these strengthened synapses, through this process of Long-Term Potentiation or LTP, are associated with memories and learning.

While we don’t know how exactly that learning of how to tie your laces is physically encoded and stored in the brain, scientists are starting to understand the mechanisms of how memories of this kind are made in the first place. There are still many questions to be answered, but those that have been have led to many findings and advancements in technology and research. Many scientists are working tirelessly to understand what exactly is happening at these synaptic connections, what molecules, what receptors, what reaction within the cell. Even computer scientists are using this model of learning and the basics of how the brain functions to model what we already do when we learn, as seen as the artificial intelligence we interact with in our daily lives. While these may seem like baby steps, they are only the first steps to answering the larger questions associated with memories and learning.

About the author:

Screen Shot 2017-12-21 at 10.59.37 PM Kush Bhatia is a PhD student in the Department of Genetics at the University of Georgia. In his spare time, he loves reading, drinking coffee, cooking, and gaming of all kinds. He also enjoys working with some high school STEM student organizations, such as the Technology Student Association. More from Kush Bhatia.