Struggling to remember a forgotten memory is an all-too-common frustration—one that unfortunately becomes more common as we age. We realize that there’s something we can’t recall, but we simply can’t raise it from the depths of our brains. So where did it go? New research published in the Journal of Neuroscience suggests these memories are still lurking in our minds, even though we think they’re long gone.
Psychologists from the University of Nottingham led by Benjamin Griffiths strapped participants into a magnetoencephalography machine to measure the magnetic fields surrounding the electrical activity in their brains. Participants were asked to vividly associate a short video clip with a word, and when they were later shown that word, they were asked to recall the video clip while psychologists monitored the magnetic activity of their brains.
They found that the brain reactivated memories whether they were consciously recalled or not, meaning the memories were there. When memories were successfully recalled, the reactivated memory signal fluctuated rhythmically in the alpha band. Alpha brain waves, research has shown, are associated with the memorization of visual information, but it was the rhythmicity of the waves that proved key to conscious recall.
Read more: “Faulty Memory Is a Feature, Not a Bug”
“What we showed is that even when the brain can reactivate the right memory, it doesn’t guarantee you’ll become aware of it,” Griffiths explained. “Instead, what seems to matter is that the memory rhythmically pulses so that it can be detected above and beyond other neural activity.”
Griffiths likened the process of consciously recalling activated memories to picking out a song or chant in the crowd at a boisterous sports stadium. “If everyone is chatting, you can’t hear what is being said, but if everyone starts singing the same song you can hear it clearly,” he explained. “We speculate that a similar idea is involved in the brain’s recall of memories.”
The team also found that conscious recall comes with a decrease in general sensory alpha wave activity—a kind of quieting of the brain’s background noise. “When the overall chatter dies down, even a modest chant from the fans becomes easier to hear,” he added.
Griffiths hopes these latest findings will change our approach to treating memory disorders like dementia.
“Current treatments often assume that when someone can’t remember, the memory itself is gone,” he said. “But if memories are being reactivated in the brain and simply failing to reach consciousness, it suggests we might need a different approach—one focused not on rebuilding lost memories, but on helping existing ones break through into awareness.”
Now if I could just remember where I put my keys … 
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Lead image: Vitalii Vodolazskyi / Shutterstock
