Brain Scans of Infants Reveal the Moment We Start Making Memories
Published in Brain Activity, Brain/Neurology.
A giggling toddler in a pink dress and matching headphones lies down on her back in front of a gigantic whirling machine. A pillowy headrest cushions her head. She seems unfazed as she’s slowly shuttled into the claustrophobic brain scanner. Once settled, a projection showing kaleidoscope-like animations holds her attention as the magnetic resonance imaging (MRI) machine scans her brain.
The girl is part of a new study seeking to answer a century-old mystery: Why can’t most us remember the first three years of our lives? Dubbed “infantile amnesia” by Sigmund Freud, the study could provide insight into how the brain develops during our early years. And if we can form memories at a young age, are they fleeting, or are they still buried somewhere in the adult brain?
It seems like a simple question, but an answer has eluded scientists.
Though infants and toddlers aren’t yet able to give detailed verbal feedback, studying their behavior has begun to shed light on if and when they remember people, things, or places. Still, the approach can’t peek in on what’s happening in the brain in those early years. MRI can.
A team from Columbia and Yale University scanned the brains of 26 infants and toddlers aged 4 to 25 months as they completed a memory task. They found that at roughly a year old, a part of the brain crucial to memory formation spun into action and began generating neural signals related to things the kids remembered from the tests.
Called the hippocampus, this sea-horse-shaped structure deep inside the brain is crucial to the encoding of our life stories—who, when, where, what. Adults with a damaged hippocampus suffer memory problems. But because wiring inside the hippocampus is still developing during our earliest years, scientists believe it may be too immature to form memories.
“It’s not that we don’t have any memories from that period [infancy],” said study author Nicholas Turk-Browne in a press briefing. “In fact, early life is when we learn our language. It’s when we learn how to walk…learn the names of objects and form social relationships.”