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Your Brain Can Resurrect 'Forgotten’ Short-Term Memories

Working memories don’t have to be continuously active in the brain to be remembered.

Grennan Milliken

Brain art. Image: Betty Lee/Flickr

Day-to-day living can be such a struggle for people with short-term memory loss. But scientists have now found that memories are rarely completely lost—instead they're just moved to the subconscious.

A functioning working memory—a part of short-term memory that deals with immediate processing of information—is critical for decision making and behavior. Without the ability to retain information where it can be easily accessed, basic cognitive functions become extremely difficult. Remembering the way to a friends house, for example, could turn into a fresh hell.

For a working memory to be maintained, scientists have long believed that the neurons associated with a memory must be continuously buzzing. But new neuroscience research published in Science suggests that it's actually possible for the brain to let a working memory go "dormant," and then fire it back up when it needs it again. This illuminates a whole new mechanism of how the brain processes memories and could perhaps help in treating people with cognitive problems in the future.

With a tiny jolt of stimulation to the brain, scientists were able to revive the "forgotten" memory.

A team of neuroscientists led by Nathan Rose of the University of Notre Dame presented a group of participants with various stimuli—a face or word—and marked one of them as "important to remember." While they were flashing the subjects different images, they also monitored their brain activity. Throughout the study the researchers pinpointed the neural activity in each person's brain that was associated with each visual cue. As people became increasingly distracted with other images, the memory of the image deemed "important" dipped down to a near silent neural pulse—almost as if it was "forgotten."

With a tiny jolt of stimulation to the brain using an electromagnetic coil, however, scientists were able to revive the "forgotten" memory and bring it back to an active neural state. This means that while subjects may have appeared to temporarily "forget" that specific memory, the brain in fact had stored it in such a way that it could be reactivated and called upon again. Rather than keeping all working memories constantly active, the brain slows some down to a dormant state—almost like it's forgotten—only to jump start it later when it needs to recall information.

Read more: A "Memory Hacker" Explains How to Plant False Memories in People's Minds

Ultimately, what the study reveals is that short-term memory is a much more layered and dynamic thing than previously thought. But the more neuroscientists unravel the inner workings of memory storage and recollection in the brain, the better positioned we'll be at understanding human cognition and perhaps reversing memory loss as well.

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