What Is Memory Consolidation?

How Short Term Memories Eventually Become Long-Term Ones

woman asleep in bed
Sleeping helps consolidate memories. Tara Moore/Getty Images

Memory consolidation is the process where our brains convert short-term memories into long-term ones. We only store short-term memories for about 30 seconds, so if we're ever going to remember anything, all that information has to be moved into long-term memory.

Memory Consolidation and Synapses 

In order to understand how memory consolidation works, it's helpful to understand how synapses work in the brain.

Think of it like an electrical system conducting a current: the synapses pass the signals from neuron to neuron, with the help of neurotransmitters. 

The more frequently signals are passed, the stronger the synapses become. This process, called potentiation, is believed to play a major role in the learning and memory processes. When two neurons fire at the same time repeatedly, they become more likely to fire together in the future. Eventually, these two neurons will become sensitized to one another.

As we acquire new experiences, information, and memories, our brains create more and more of these connections. Essentially, the brain can rearrange itself, establishing new connections while weeding out old ones.

How Memory Consolidation Works

By rehearsing or recalling information over and over again, these neural networks become strengthened. For example, if you study the same material regularly over a long period, the pathways involved in remembering that information becomes stronger.

The repeated firing of the same neurons makes it more likely that those same neurons will be able to repeat that firing again in the future.

As a result, you will be able to remember the information later with greater ease and accuracy.

Another way to think of these synaptic pathways: They're similar to a path in the woods.

The more often you walk the path, the more familiar it becomes and the easier it is to traverse.

Influences on the Memory Consolidation Process

While we often think of the brain as being like a filing cabinet or a computer, carefully storing away specific memories in individual files, memories are spread out across the entire brain. Through the consolidation process, the brain creates a sort of neural map, allowing memories to be retrieved when they are needed.

Experts suggest that sleep can play an important role in the consolidation process. One of the major theories of sleep suggests that sleep exists as a way to process and consolidate information that we have acquired during our waking lives.

People often think of memories as permanent, but just because a memory has been consolidated does not mean that it can't be lost. In fact, researchers have found that memories often need to be reconsolidated once they have been recalled. The process of recalling and reconsolidating a memory can help maintain and strengthen information in long-term memory.

Researchers have also found that memories need to be reconsolidated every time they are accessed. This process, however, can transform and change the memory itself.

The very act of remembering, it seems, can actually lead to some things being forgotten.

Speeding Up the Memory Consolidation Process

It is also possible to speed up the consolidation process when learning new information. Rehearsal and memorization strategies, like studying and mnemonic devices are a few techniques, and one of the best ways to ensure that information is consolidated into long-term memory is to rehearse it over several spaced intervals repeatedly.

That's why going over your class notes once a week for several weeks will lead to greater memory retention than cramming the night before an exam.

Sources

Payne, J. D., & Kensinger, E. A. (2010). Sleep’s role in the consolidation of emotional episodic memories. Current Directions in Psychological Science, 19(5), 290-295. doi: 10.1177/0963721410383978 

Milner, B.; Corkin, S.; Teuber, H. -L. (1968). Further analysis of the hippocampal amnesic syndrome: 14-year follow-up study of H.M. Neuropsychologia 6(3), 215. doi:10.1016/0028-3932(68)90021-3

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