Written by Maria Cohut, Ph. Share on Pinterest New research pins down the steps of simple memory recall. Abstract categories come first. Latest news Could 'cupping' technique boost vaccine delivery? Scientists identify new cause of vascular injury in type 2 diabetes. Adolescent depression: Could school screening help? In the s, scientists analyzed high-resolution brain scans and found that these fleeting memories depend on neurons firing in the prefrontal cortex, the front part of the brain responsible for higher-level thinking.
But if too much stuff keeps coming in, your short-term memory gets overloaded and the first [bits of information] will get kicked out. By contrast, long-term memory is the treasure trove of knowledge and past events collected throughout our lives.
And while short-term memories are supported by blips of neural activity, long-term memories actually forge a physical presence in the brain. When a long-term memory is formed, the connections between neurons, known as synapses, are strengthened.
In some cases, entirely new synapses are created. And the more we revisit memories, activating these neural pathways, the stronger the connections become— like trampling your way through the woods to create a well-trodden path. Long-term memories can also take several different forms. For example, implicit memories are the basis for automatic behaviors like tying your shoes or brushing your teeth.
These instinctive actions take place in the unconscious part of the brain. These are split between episodic and semantic memory. The latter describes specific, conceptual knowledge, like the date on which the Declaration of Independence was signed. Episodic memory describes events and experiences from your own life. Everything from your 21st birthday party to your trip to Europe falls into this category.
The things we do in life leave traces behind, embedded in our memories. Much like Marcel Proust biting into his much-loved madeleines , causing once-forgotten memories from his childhood to come flooding back, memory traces can conjure vivid sesnory experiences of things past.
Since the days of ancient Greece, scholars have speculated that these remnants might even alter the physical makeup of the brain. In , a German scientist named Richard Semon suggested that these traces, which he called memory engrams, are represented as physical changes in the brain after an event or experience.
More than years passed. Then, in , scientists started using optogenetics, a technique for stimulating neurons that are genetically modified to respond to pulses of blue light. With this new technology, it was possible to localize and identify the specific neurons that carry memory engrams in animals.
In a Nature study, Tonegawa and researchers at MIT and Stanford University used optogenetics to demonstrate that our memory traces do indeed live in specific clusters of brain cells.
Electrical activity that cycles 30 or more times per second is involved in representing brain activity during sensory processing [ 4 ]. So, if you try to remember more than seven pieces of information at the same time, your brain might process all of the sensory information, but you might not actually remember all of the information later. This may be because more than seven items exceeds the capacity of the slower memory component — that is, the WM cycle [ 4 ].
Now, let us do the math. The answer is 6, which is consistent with our limited WM capacity of five to seven pieces of information. The number of times faster electrical currents fit into the slower WM electrical cycles might actually determine our WM capacity limits [ 4 ]! Have another look at Figure 1 for a picture of how the number of pieces of information represented in electrical activity that cycles 30 or more times per second can fit into a memory cycle three to eight cycles per second.
This relationship between fast- and slow-cycling electrical activities is important to how neurons make memories. Depending on how much information needs to be processed, the brain can speed up or slow down the slower, WM wave within the range of three to eight repeating cycle per second. Therefore, this slow rhythm can adapt, which helps the brain group the fast rhythm into meaningful pieces of information.
Thinking again to Box 1 Figure 2 , it may be easier to remember two-colored flags than to remember six colors in order, but it is more complicated to remember two flags of three colors each than it is to remember two single colors. As mentioned above, the slower-cycling WM electrical activity is adaptive.
This means that the WM cycle might slow down, from eight to three cycles per second, to incorporate more pieces of sensory information in one WM cycle [ 4 ].
Another way that the brain supports WM for chunked information is that the WM cycle organizes the sensory information in order based on timing [ 5 ]. In Figure 2 , the first red-colored item occurs before the blue item, and the two red items occur at different times, separated in order by three other items. When we only have to remember two items, red and blue, the order of red-then-blue is simple. But, when we have to remember six items, the timing becomes more complicated — and important.
This means that as we hold onto and process more and more pieces of information, the order in which different pieces of information enter the WM cycle becomes more and more important to WM function. The fast-cycling electrical activity, which represents pieces of sensory information and reflects the firing of neurons [ 2 ], actually occurs in ordered time slots within the slower WM cycle [ 5 ].
Putting it all together, electrical signals recorded from the human brain show us that we hold onto and process pieces of information in coordinated patterns of activity [ 2 — 5 ]. Neurons make memories by firing together in specific parts of the brain. That might be one mechanism for remembering multiple pieces of information at the same time. This complicated WM system allows us to make memories, and it may also be the reason why remembering a lot of things at the same time is so hard!
Think back to Figure 2 again. In order to remember all six-colored items, we asked you to think about them as two-colored flags. Chunking is a very effective strategy for remembering multiple things at the same time. As mentioned above, the brain uses the timing of the faster electrical waves to incorporate more and more information into each slower WM cycle. By chunking a lot of information into a single item or event, we are allowing our brains to handle more pieces of information.
Usually, the brain automatically breaks incoming information into manageable pieces, making the information easier to process.
You can also actively use chunking to improve your memory, for example, when you study to learn information. You can associate and combine different pieces of information, however, you would like in order to make chunks. Your brain can actually use the timing of different cycles of electrical activity to make sense of relationships based on time, space, emotions, or anything else that holds meaning for you [ 6 ].
For example, think about two events that happened yesterday, such as talking to a friend and eating dinner. Research shows it can be more valuable in terms of remembering than having more intellectual capabilities in the first place, and that it can be more effective for remembering than straightforward repetition and memorization. For example, he says, how many Americans could accurately draw the details of the dollar bill, even though they likely look at it all the time?
Based on the neuroscience explanation of how memory works, if you really want to remember something, your best bet is trying to connect it to some other part of your life or a topic you already know, Richards adds. Want more tips like these? Sign up for our newsletter and follow us on Facebook , Twitter and Instagram. IE 11 is not supported.
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